Tag: Korean cosmetics

Firmness Actives in Korea: Wrinkle Is Notified, Elasticity Is Substantiated

Hello, this is Dr. J. Today, five actives people reach for when they want firmer skin — chosen by what the human studies actually measured.

Start with the odd part. In Korea, the regulator reviews “wrinkle improvement” and names the actives for it. It does not use the word elasticity anywhere in that table. Instead it wrote down how to measure elasticity, in a different document.

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Primary sources

📄 Functional Cosmetics Review Regulation, Annex 4 (Korea Law Service)

📄 MFDS, Guideline on test methods for claim substantiation (March 2018, PDF, Korean)

📄 Hyaluronic acid, 8-week study (J Clin Aesthet Dermatol 2014)

📄 0.4% retinol, 24-week trial (Arch Dermatol 2007)

Annex 4 holds six claim categories. The guideline holds ten test methods. Elasticity appears in the second document only.

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The short version

● Korea notifies six claim categories, and wrinkle improvement names four actives
● The word elasticity is not in that table
● Chapter 2 of the substantiation guideline is “Skin elasticity improvement”
● A Cutometer® or Dermaflex® applies negative pressure and measures the return
● So the test to apply to a product is: what did the study measure?

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How Korea splits one face into two boxes

Korean cosmetics law carves out a class called functional cosmetics. For each claim in that class the regulator publishes an annex that names the active and the percentage, and a product built to those numbers is spared from filing new efficacy data. Annex 4 is that table.

Category	What the annex sets	Reading
UV protection and tanning	Actives and maximum percentages	Both the name and the number are fixed
Whitening	Nine actives (arbutin 2–5%, niacinamide 2–5%, and others)	Same
Wrinkle improvement	Four actives (retinol 2,500 IU/g, adenosine 0.04%, and others)	The box next to today’s subject
Hair colour change	A list of dye actives	Same
Hair removal	Thioglycolic acid 3.0–4.5%	A single active
Acne relief	Salicylic acid 0.5%	Same
Firmness / elasticity	No category at all	Not a claim the regulator reviews

The wrinkle box, in full

Active	Percentage	Reading
Retinol	2,500 IU/g	One of the few set in international units
Retinyl palmitate	10,000 IU/g	A larger number than retinol
Adenosine	0.04%	The smallest percentage of the four
Polyethoxylated retinamide	0.05–0.2%	Written as a range

Annex 4, wrinkle entry — as written

Dosage forms: “limited to lotions, solutions, creams and impregnated masks”
Claim: “helps improve skin wrinkles”
Directions: “apply an appropriate amount evenly to the skin; or apply the product to the skin, remove the support after 10–20 minutes and spread the remaining product evenly (impregnated masks only)”

Even the sentence a brand may print is fixed. Elasticity is in none of those cells.

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What exists instead: a written test method

The second document is a civil petitioner guideline published by the Ministry of Food and Drug Safety in March 2018. It sets out how to substantiate ten claims that fall outside the functional class.

Chapter	Claim	Added
Ch. 1	Skin moisturisation	2012.5 (original)
Ch. 2	Skin elasticity improvement	2012.5 (original)
Ch. 3	Sebum control	2012.5 (original)
Ch. 4	Temporary cellulite reduction	2013.11
Ch. 5	Suitable for acne-prone skin	2013.11
Ch. 6	Dark circle relief	2014.8
Ch. 7	Improved skin blood flow	2015.12
Ch. 8	Puffiness relief	2015.12
Ch. 9	Paraben-free	2017.3.31
Ch. 10	Fine dust protection	2018.3.28

Chapter 2, Skin elasticity improvement — the guideline’s own sentences

“This is a test in which a Cutometer® or Dermaflex® applies negative pressure to the skin and measures the degree to which it returns to its original state”
“The number of subjects shall provide at least 20 sets of valid data so that statistical comparison is possible”
“from among adult men and women aged 20 or over”
“The test site shall be the whole face, including the eye area (the measurement site)”

The conditions are written down as well: no air movement or direct sunlight, 20–24 °C and 40–60% relative humidity, 30 minutes of acclimatisation before measurement, a significance level of 0.05, and non-parametric tests as the default when an arm holds 30 subjects or fewer.

⚠ What Chapter 2 does not contain is as telling. There is no list of permitted wordings and no pass mark, and no parameter is named — R2, R5 and R7 appear nowhere. The state writes the procedure and leaves the threshold open.

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One study measured elasticity directly — hyaluronic acid

33 women, mean age 45.2 ± 3.9, over 8 weeks at a contract institute in Hamburg. A low molecular weight hyaluronic acid lotion, serum and cream were applied twice a day to the whole face, with measurements at baseline and on days 15, 29 and 57.

Elasticity was read with a Cutometer, and the treated side rose significantly above the untreated side. Moisture, roughness and erythema were measured too; the only p value printed in the body of the paper belongs to erythema.

The weak points belong in the same paragraph. The “up to 55%” figure lives in the abstract and is not carried into the text, no p value is given for elasticity, and there is no placebo arm — the comparison is with an untreated area. The concentration of the product is not disclosed either.

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Two are notified actives — retinol and adenosine

The retinol trial measured wrinkles. 36 residents of two long-term care facilities, mean age 87, were followed for 24 weeks in a randomised, double-blind, vehicle-controlled design: 0.4% retinol lotion on one arm, its vehicle on the other, up to three times a week.

Fine wrinkling scores changed by −1.64 (95% CI −2.06 to −1.22) with retinol against −0.08 (−0.17 to 0.01) with vehicle, P<.001. In biopsy subsets, glycosaminoglycan expression rose (P=.02) and procollagen I staining increased (P=.049).

That trial measured no elasticity. It measured wrinkle scores and tissue markers. Adenosine, meanwhile, carries a number the regulator chose: 0.04%, set in Annex 4, not by the brand.

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One looked at the fibres — vitamin C 5%

A 5% ascorbic acid cream was compared with its own excipient for 6 months, double-blind, applied daily, with assessments at baseline, 3 months and 6 months and biopsies at the end.

Global scores from both the dermatologist and the volunteer improved against control, the density of the skin microrelief rose and deep furrows fell. Electron microscopy showed repair of elastic tissue, consistent with the clinical and surface findings.

Two limits: the number of participants is not stated in the abstract (healthy female volunteers with photoaged skin is as far as it goes), and what this study saw is tissue, not an elasticity reading.

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One was measured by mouth — collagen peptides

69 women aged 35–55, 23 per arm, took 2.5 g or 5.0 g of collagen hydrolysate or placebo once daily for 8 weeks, with a 4-week follow-up after the supplement stopped.

Both doses improved skin elasticity against placebo at 8 weeks, and four weeks after stopping, elasticity remained significantly higher in the older women. Hydration and transepidermal water loss moved in subgroup analysis but not significantly.

This one is not applied to the skin. It belongs on a different shelf from the jar, and the exact figures, p values and the instrument used sit behind a paywall this piece could not open.

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The five in one table

Active	Subjects	Duration	Design	Measured	Result
Hyaluronic acid	33	8 weeks	Treated vs untreated area	Elasticity	Significantly higher on the treated side
Retinol 0.4%	36	24 weeks	Randomised, double-blind, vehicle	Wrinkles, tissue	−1.64 vs −0.08 (P<.001)
Adenosine 0.04%	—	—	Set by Annex 4	—	Notified for wrinkle improvement
Vitamin C 5%	not in abstract	6 months	Double-blind, vehicle	Elastic tissue	Repair on electron microscopy
Collagen peptides	69	8 weeks	Randomised, double-blind, placebo	Elasticity (oral)	Both doses above placebo

And where each one is weak

Active	What this study cannot say
Hyaluronic acid	The 55% figure is abstract-only; no p value for elasticity and no placebo arm; the concentration is undisclosed
Retinol	It did not measure elasticity. The cohort is also a mean age of 87 in residential care, which does not transfer cleanly to younger skin
Adenosine	What the regulator approved is wrinkle improvement, not an elasticity figure
Vitamin C	No participant count in the abstract, and it looked at tissue rather than an elasticity reading
Collagen peptides	Not a topical result. The numbers, p values and instrument could not be verified in the full text

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Korea, the United States and the EU — reviewed names and proven names

	Korea	United States	EU
Ingredient list per claim	Annex 4 of the functional cosmetics regulation — actives and percentages for six claims	None	Positive lists cover colorants, preservatives and UV filters only (Regulation 1223/2009, Art. 14)
“Wrinkle”	Reviewed or notified before sale as a functional claim	No approved list of claims	Handled as a claim, under the common criteria
“Elasticity”	Chapter 2 writes down the measuring procedure	No procedure written by the regulator	The six common criteria demand evidence
In their words	“a Cutometer® or Dermaflex® applies negative pressure to the skin…”	“FDA does not have a list of approved or accepted claims for cosmetics”	“adequate and verifiable evidence” · “state of the art practices” (655/2013)
When it is checked	Functional claims before sale; elasticity when asked	No pre-market approval for cosmetics	No pre-market approval; the evidence must exist

Lined up, the Korean position is unusual in a specific way. One face, two boxes. The claim closest to firmness — wrinkles — is handled by ingredient, in advance. Firmness itself is handled by procedure, afterwards. Neither the United States nor the EU keeps the first box for this kind of claim at all, which is why an exporter reads the two sentences in opposite order: in Seoul the first question is which active and what percentage, and in Brussels or Washington it is what evidence is on file.

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What was left out, and why

✔ The niacinamide elasticity trial (Bissett et al., Dermatol Surg 2005) — the abstract could not be opened at a primary source today. Europe PMC returned 429 on all three attempts and Wiley, the journal’s own full text and Semantic Scholar all errored
✔ Injected hyaluronic acid (mesotherapy) — a procedure, not a cosmetic
✔ Lasers, radiofrequency and thread lifts — same reason
✔ Madecassoside — the primary sources found were reviews
✔ A green tea study (Chiu 2005) — oral and topical treatment were given together, so neither arm can be read alone
✔ A pass mark for Chapter 2 — the guideline does not set one

About the author · Dr. J

MS in Veterinary Medicine, PhD in Life Sciences. I worked as a researcher at the Korea Research Institute of Bioscience and Biotechnology (KRIBB) and now run Beaurea, a cosmetics manufacturing company, where I write the formulas myself. This blog reads the research papers and the regulatory documents and turns them into plain-language criteria for choosing ingredients. I don’t recommend specific products here – only criteria that apply to any product.

📌 Related

📌 Adenosine 0.04%: who decided that number — the box next door, wrinkle improvement

📌 Hyaluronic acid: how to read the molecular weight — the one active here that measured elasticity

📌 Collagen: topical vs oral — the longer version of the oral section

📌 Pores and sebum: the test method the regulator wrote down — Chapter 3 of the same guideline

📄 References

· Functional Cosmetics Review Regulation, Annex 4 (Korea Law Service, read 21 October 2026)

· MFDS, Guideline on test methods for the substantiation of cosmetic labelling and advertising (civil petitioner guideline, March 2018), Chapter 2

· Jegasothy SM, Zabolotniaia V, Bielfeldt S. J Clin Aesthet Dermatol 2014;7(3):27-29

· Kafi R, Kwak HSR, Schumacher WE, Cho S, Hanft VN, Hamilton TA, King AL, Neal JD, Varani J, Fisher GJ, Voorhees JJ, Kang S. Arch Dermatol 2007;143(5):606-612

· Humbert PG, Haftek M, Creidi P, Lapière C, Nusgens B, Richard A, Schmitt D, Rougier A, Zahouani H. Exp Dermatol 2003;12(3):237-244

· Proksch E, Segger D, Degwert J, Schunck M, Zague V, Oesser S. Skin Pharmacol Physiol 2014;27(1):47-55

· U.S. FDA, “Cosmetics Labeling Claims” (content current as of 21 November 2022)

· Commission Regulation (EU) No 655/2013, common criteria · Regulation (EC) No 1223/2009, Article 14

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This article summarises published research and public regulatory documents; it is not medical advice. Annex 4 and Chapter 2 of the substantiation guideline were read at source on 21 October 2026, and the Korean documents are quoted here in translation. Of the four studies, one does not state its participant count, one measured no elasticity at all, and one was taken by mouth. Those facts are in the tables. Ingredient names and percentages are given as criteria for reading a product, not as a recommendation of any product.

— Dr. J Ingredient Notes

October 21, 2026

Exfoliating Actives in Korea: No Claim Category, but a Label Rule

🇰🇷 한국어판

Hello, this is Dr. J. Today we are looking at exfoliating actives in Korean cosmetics, and at what the studies behind them actually measured.

Here is the part most guides skip. Exfoliation is not a reviewed claim in Korea. It is not one of the six notified categories, and it is not one of the ten official test methods. Yet the label rules name it anyway.

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The primary documents

📄 Regulation on the Examination of Functional Cosmetics, Annex 4

📄 Regulation on Safety Standards for Cosmetics, Annex 2

📄 MFDS Guideline on Test Methods for Substantiating Cosmetic Claims (March 2018, PDF)

📄 U.S. FDA, Alpha Hydroxy Acids

📄 Stiller MJ et al., Arch Dermatol 1996 (22 weeks, 74 women)

Annex 4 names six categories; the guideline names ten test methods. Exfoliation is in neither.

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The short version

✔ Korea notifies actives in six categories, and exfoliation is not one of them
✔ The regulator’s ten test methods do not cover it either
✔ Above 0.5% AHA a sun sensitivity warning becomes mandatory on the box
✔ Even a 10-50 mL package that shortens its ingredient list cannot drop fruit acid (AHA)
✔ So the useful question is what each study measured

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1. Korea notifies actives by claim, and exfoliation is missing

Korea runs functional cosmetics as a positive list. For each claim the notification names the ingredient and the percentage, and it also fixes the dosage form and the wording a company may print.

Category	What the notification sets	How to read it
UV protection and tanning	27 ingredients with maximum levels	Both the name and the number are fixed
Brightening	Nine ingredients (arbutin 2-5%, niacinamide 2-5% and others)	Same
Wrinkle improvement	Four ingredients (retinol 2,500 IU/g, adenosine 0.04% and others)	Same
Hair colour change	Dye lists split across six tables	Same
Hair removal	Thioglycolic acid 3.0-4.5%, pH 7.0 to below 12.7	A single ingredient
Acne-prone skin relief	Salicylic acid 0.5%, in cleansing products of soap composition	One of today’s five sits here
Exfoliation	There is no category	So there is nothing to be reviewed for

The last row is the point of this article. There is no exfoliation category, so there is nothing for a company to be reviewed against, and no notified percentage to compare a product with.

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2. There is no test method for it either

Separately from the notification, the Ministry publishes a guideline that sets out how to measure each claim: who the subjects are, which instrument is used, and what counts as a result. It has grown one claim at a time.

Chapter	Claim	Added
1	Skin hydration	2012, at the start
2	Skin elasticity	2012, at the start
3	Sebum control	2012, at the start
4	Temporary reduction of cellulite	2013
5	Suitable for acne-prone skin	2013
6	Dark circles	2014
7	Skin microcirculation	2015
8	Puffiness	2015
9	Paraben-free	31 March 2017
10	Fine dust protection	28 March 2018
—	Exfoliation	Never added

Ten chapters, added over six years, and exfoliation never arrived. In our earlier pieces the pattern was different each time: for sensitive skin the phrase appeared only as a subject exclusion criterion, and for sebum there was a full chapter with a Sebumeter procedure. Exfoliation is the third case — absent from both documents.

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3. The label rules name it even so

A claim category is one instrument. A label rule is another, and Korea uses the second here. Once a product passes 0.5% AHA, a notification requires fixed sentences on the box.

When it applies	What the box has to say
AHA above 0.5%	The product may increase the skin’s sensitivity to sunlight, so use a sunscreen alongside it (rinse-off and hair products are excepted).
Same threshold	Test it on a small area first and check for a skin reaction.
AHA above 10%, or pH below 3.5	The product contains a high concentration of AHA and may cause adverse effects, so consult a physician.

So the sunscreen sentence you find on the back of a Korean exfoliating toner is not marketing. It is text a notification requires, and its trigger is a concentration.

The second place is the ingredient list. Small containers may shorten it, but six things stay.

Enforcement Rule of the Cosmetics Act, Article 19(2)3 — what a small package may not drop

A package holding more than 10 mL and up to 50 mL (or more than 10 g and up to 50 g) may omit ingredient labelling, except for:
(a) tar colourants · (b) gold leaf · (c) the type of phosphate in shampoos and rinses
(d) fruit acid (AHA) · (e) ingredients that produce the effect of a functional cosmetic · (f) ingredients for which the Minister has notified a blending limit
※ Where labelling is omitted, the company must let consumers check the full list by telephone or website, or keep a printed list at the point of sale (paragraph 5).

An active with no claim category of its own is still named in the labelling rules. That is the shape of this subject in Korea.

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4. Roughness: the two AHAs did not behave the same

The cleanest cosmetic-strength trial here is old and still useful. 74 women aged 40 to 70, 22 weeks, randomised, double blind and vehicle controlled, applying 8% glycolic acid or 8% L-lactic acid twice a day to the face and outer forearms.

On the face, at least one grade of improvement was reached by 76% on glycolic acid, 71% on lactic acid and 40% on the vehicle.

On the forearm the two parted company. Lactic acid beat the vehicle for roughness; glycolic acid beat it for overall photodamage and sallowness but not for roughness. If you have read that the AHAs are interchangeable, this is the trial that complicates it.

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5. Horny layer thickness: urea

A separate study compared urea 2% cream, 10% cream and 10% foam against petrolatum and untreated skin, in healthy volunteers and in people with type I and type II diabetes.

The 10% cream slightly lowered transepidermal water loss and reduced horny layer thickness, with no excessive occlusion from any of the products.

Korea’s safety standards set the ceiling for urea at 10%, so the concentration the study used sits at the regulatory limit rather than below it.

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6. The one Korea notifies: salicylic acid 0.5%

Regulation on the Examination of Functional Cosmetics, Annex 4 — acne-prone skin relief

Ingredient and level: salicylic acid 0.5% · Product type: cleansing products of soap composition · Forms: solution, lotion, cream
Claim: “helps relieve acne-prone skin”
Directions: apply an appropriate amount to the skin and rinse off immediately with water

The directions matter as much as the percentage. What the notification covers is a rinse-off cleanser, not a leave-on treatment.

The safety standards then split the ceiling three ways: 0.5% when used as a preservative, 2% in personal cleansing products, and 3% in rinse-off hair products — the latter two only where it is the active of a functional cosmetic.

One more line sits with it: salicylic acid may not be used in products for infants, or in products labelled for children aged 13 or under, with shampoo excepted.

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7. Irritation: PHA (lactobionic acid)

Lactobionic acid at 10% was held under a 24 hour occlusive patch in 10 volunteers, with transepidermal water loss, erythema and stratum corneum hydration read afterwards. No irritation appeared.

The hydration arm of the same paper ran in 16 volunteers over 3 hours and 21 days, and there the authors are direct: a statistically significant difference between the placebo and the sample with lactobionic acid was not observed.

Read together, PHA is an ingredient with mildness shown rather than strength shown. That is worth separating when a product page offers it as a gentler route to the same result.

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The five side by side

Ingredient	People	Duration	Design	Measured	Result
Glycolic acid 8%	74, shared	22 weeks	Randomised, double blind, vehicle controlled	Facial grade, forearm roughness	Face 76% vs vehicle 40%; no difference in roughness
Lactic acid 8%	74, shared	22 weeks	Same trial	Facial grade, forearm roughness	Face 71%; roughness also beat vehicle
Urea 10%	not in abstract	not in abstract	Compared with petrolatum and untreated skin	Water loss, horny layer thickness	Horny layer thickness fell
Lactobionic acid 10%	10 and 16	24 h and 21 days	Patch test and hydration arm	Irritation, hydration	No irritation; hydration no different from placebo
Salicylic acid 0.5%	—	—	Notified active	—	Acne-prone skin relief

The endpoints are not interchangeable. Roughness, horny layer thickness and irritation are three different measurements, and a product page that says “clinically proven” rarely says which one it means.

And where each study is weak

Study	Where it is weak, stated plainly
Stiller 1996	The facial endpoint is an investigator grade, and roughness was read on the forearm. One participant withdrew for irritation and six for personal reasons.
Borelli 2011	The abstract gives neither the number of participants nor the overall duration. Healthy volunteers and diabetic patients were studied together.
Tasic-Kostov 2011	Hydration showed no significant difference from placebo. The irritation arm is a single 24 hour patch in 10 people.
Salicylic acid	No human trial is attached here — only the level and the directions the notification sets.

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8. Korea, the United States and the EU — the same two numbers, different force

No regulator here keeps a claim list for exfoliation. What differs is which instrument fills the gap.

	Korea	United States	European Union
Claim-based ingredient list	Six categories; exfoliation is not one	None — “FDA does not have a list of approved or accepted claims for cosmetics”	Permitted lists cover colourants, preservatives and UV filters (Art. 14)
Test procedure	Ten chapters; exfoliation is not one	Not written down	655/2013 requires “state of the art practices”
AHA and sunlight	Mandatory label text by notification, above 0.5%	Recommended Sunburn Alert, in a guidance	No entry found for this
The same two numbers	Above 10%, or pH below 3.5, adds a line	CIR found 10% or less and pH 3.5 or greater safe	—
Force of the document	Omitting the text is a labelling breach	“do not establish legally enforceable responsibilities”	Common criteria bind; the method is a condition

The striking part is the arithmetic. Korea’s notification adds the physician line above 10% AHA or below pH 3.5. In the United States, the Cosmetic Ingredient Review panel concluded that glycolic and lactic acid are safe where the concentration is 10 percent or less and the final product has a pH of 3.5 or greater. The same two numbers, drawn from the opposite side.

What separates them is the document. Korea’s sits in a notification, so leaving the sentence off the box is a labelling breach. The United States puts its Sunburn Alert wording in a guidance issued in January 2005, and FDA states plainly that its guidances “do not establish legally enforceable responsibilities” and “should be viewed only as recommendations”.

The EU does not run a claim-based ingredient list at all. Article 14 of Regulation (EC) No 1223/2009 keeps positive lists for colourants, preservatives and UV filters, and claims are governed instead by Regulation (EU) No 655/2013: they “shall be supported by adequate and verifiable evidence”, and that evidence “shall take into account state of the art practices”.

For anyone exporting into Korea, the practical reading is short: there is no exfoliation dossier to file, and the compliance work sits on the label instead.

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What to check on the box

✔ Ask what was measured — roughness, horny layer thickness or hydration
✔ A sun sensitivity sentence on the box means the product is above 0.5% AHA
✔ For salicylic acid, the ceiling depends on whether the product is rinsed off
✔ Even a small container lists fruit acid (AHA)

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One line

Exfoliation is not a reviewed claim in Korea; it is a labelled one. Decide which endpoint matters to you — roughness, horny layer thickness or mildness — and the list of five becomes a list of two.

Next: five actives for skin elasticity — chapter 2 of the same guideline, and unlike exfoliation, a claim with a written test procedure.

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What is not in this article, and why

✔ Peel and chemical resurfacing trials — those are procedures, not cosmetics. Only leave-on cosmetic strengths of 8 to 10% were used here
✔ A urea dose-ranging study (Addor et al., Surg Cosmet Dermatol) — the journal page carries no publication year, volume or pages, so it could not be cited properly
✔ A gluconolactone study (PMID 33769633) — Europe PMC returned 429 and PubMed a reCAPTCHA
✔ Enzyme and physical scrubs — no human study was found
✔ Whether Annex III of Regulation 1223/2009 carries entries for glycolic or lactic acid — the annex table could not be opened, so this is recorded as not found rather than as absent

About the author · Dr. J

📌 Related

📌 Acne Skincare Ingredients and Korea’s 0.5% Salicylic Acid Rule — the same salicylic acid entry, read from the acne side

📌 Pores and Sebum: the Test Method the Regulator Wrote Down — the mirror image of today’s piece

📌 Is Glycolic Acid an AHA? AHA vs BHA, Explained — the two acids in today’s trial

📌 Salicylic Acid (BHA): 0.5% vs 2%, Explained — why the ceiling splits

📄 Sources

· Regulation on the Examination of Functional Cosmetics, Annex 4 (Korea Law Information Center, accessed 20 October 2026)

· Regulation on Safety Standards for Cosmetics, Annex 2 (same, accessed 20 October 2026)

· MFDS, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising Claims (March 2018, no. 0353-02)

· Notification on Cautions in Use and Labelling of Fragrance Allergens in Cosmetics (cross-checked on the Korea Cosmetic Association ingredient dictionary)

· Enforcement Rule of the Cosmetics Act, Article 19 (Korea Cosmetic Association, statute page)

· Stiller MJ, Bartolone J, Stern R, Smith S, Kollias N, Gillies R, Drake LA. Arch Dermatol 1996;132(6):631-636

· Borelli C, Bielfeldt S, Borelli S, Schaller M, Korting HC. Int J Cosmet Sci 2011;33(1):37-43

· Tasic-Kostov MZ, Reichl S, Lukic MZ, Jaksic IN, Savic SD. Pharmazie 2011;66:862-870

· U.S. FDA, “Alpha Hydroxy Acids”; “Guidance for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids” (January 2005); “Cosmetics Labeling Claims”

· Regulation (EC) No 1223/2009, Article 14 · Regulation (EU) No 655/2013, Annex

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This article summarises published studies and public regulatory documents; it is not medical advice. The Korean notifications and annexes were opened in the original on the day of writing, and the AHA warning wording was taken from two Korea Cosmetic Association ingredient pages that matched word for word, because the notification annex PDF could not be opened. Of the studies cited, one does not report its participant count and one endpoint showed no difference from placebo; both are stated in the tables. Ingredient names and percentages are given as criteria for choosing a product, not as a recommendation of any particular one.

— Dr. J Ingredient Notes

October 20, 2026

Sensitive Skin Ingredients: The Category No Regulator Names, and Five with Human Studies

🇰🇷 한국어판

Hello, this is Dr. J. Today I want to pick five ingredients for sensitive skin the only way that is left — from studies done on people.

One thing first, because it sets up everything else. Sensitive skin barely appears in the rules at all. Where it does appear, it is not as something to measure. It is a reason to exclude someone from a test.

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The sources, first

📄 Regulation on Review of Functional Cosmetics, Annex 4 (Korean Law Service)

📄 MFDS, Guideline on Test Methods for Substantiating Cosmetic Claims (2018-03, PDF)

📄 U.S. FDA, “Hypoallergenic Cosmetics”

📄 Regulation (EC) No 1223/2009, Article 14

Six categories in the Korean annex, ten methods in the guideline. Sensitive skin is in neither.

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Five lines, if you are in a hurry

✔ Korea notifies actives in six categories, and sensitive skin is not one

✔ The MFDS test-method guideline lists ten methods, and sensitive skin is not one either

✔ In those tests, sensitive skin is an exclusion criterion

✔ The United States wrote a definition for “hypoallergenic” in 1975 and lost it in court

✔ So five ingredients are picked here from human studies, weaknesses included

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What Korea names, and what it leaves out

Korea’s functional cosmetics system works from a notified list. Annex 4 of the Regulation on Review of Functional Cosmetics sets out the ingredient and the amount. Make a product to those numbers and you do not have to file fresh efficacy data — which is another way of saying the state has already decided what counts.

Category	What the notification sets out	How to read it
UV protection	27 ingredients with maximum amounts	Names and numbers are both fixed
Brightening	Nine ingredients (arbutin 2–5%, niacinamide 2–5% and others)	Same
Wrinkle improvement	Four ingredients (retinol 2,500 IU/g, adenosine 0.04% and others)	Same
Hair colour change	A dyeing list split across six sub-tables	Same
Hair removal	Thioglycolic acid, 3.0–4.5% as the acid, pH 7.0 to under 12.7	One ingredient
Acne relief	Salicylic acid 0.5%, in cleansing products	One ingredient
Sensitive skin	Nothing	There is no such category

Acne gets one ingredient. Sensitive skin gets no category at all. So “for sensitive skin” and “low irritation” on a Korean box are not reviewed phrases.

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There is no method to measure it either

This is the part that is specific to Korea, and it is worth knowing if you sell there. The MFDS publishes a separate guideline that tells you how to run the test behind a claim — which instrument, how long, what unit. Each claim gets its own chapter.

Chapter	Test method	Added
1	Skin moisturising	2012-05, at issue
2	Skin elasticity	2012-05, at issue
3	Sebum control	2012-05, at issue
4	Temporary reduction of cellulite	2013-11
5	Suitability for acne-prone skin	2013-11
6	Dark circle improvement	2014-08
7	Skin blood-flow improvement	2015-12
8	Puffiness reduction	2015-12
9	Paraben-free	2017-03-31
10	Fine-dust blocking	2018-03-28
—	Sensitive skin, low irritation	Not among the ten

Moisturising is there. Sebum is there. Dark circles are there. Sensitive skin is not.

★ The one place “sensitive” does appear

In the subject-selection rules for chapters 1, 2 and 3 — moisturising, elasticity and sebum — one of the exclusion criteria is “people with sensitive or hyper-reactive skin”. Chapter 5, on acne-prone skin, excludes “people whose skin is sensitive to adhesive components”.
So in this document sensitive skin is not something you measure. It is something you screen out before you measure anything else.

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The United States tried, and the courts said no

The American story is the sharpest of the three, because the definition existed and then stopped existing.

When	What happened	Where it stands
February 1974	FDA proposed a regulation on the term hypoallergenic	A definition was on the table
6 June 1975	FDA issued the final regulation	Manufacturers would have had to test
On appeal	The court held FDA’s definition was unreasonable	The regulation fell
Today	«There are no Federal standards or definitions that govern the use»	«The term means whatever a particular company wants it to mean»

FDA’s own page puts it plainly: «There are no Federal standards or definitions that govern the use of the term “hypoallergenic.”» And then, one sentence later: «The term means whatever a particular company wants it to mean.»

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The EU names actives for three jobs, and claims are not one of them

It is easy to assume the EU, with its long annexes, must have a list somewhere. It does not — not for claims.

Annex	What it is	What that means for a claim
Annex II	Prohibited substances	A list of what cannot go in at all
Annex III	Restricted substances	Conditions, not a permitted list
Annex IV	Colorants — permitted list	A colorant not listed cannot be used
Annex V	Preservatives — permitted list	Same
Annex VI	UV filters — permitted list	Same
For a claim	No annex	Evidence under Reg. 655/2013 instead of a list

Article 14 is a list of prohibitions. Three of them work as permitted lists, because a colorant, a preservative or a UV filter that is not in its annex cannot be used. There is no fourth annex for “soothing” or “for sensitive skin”. Under Regulation (EC) No 655/2013 a claim has to rest on «adequate and verifiable evidence» instead, and the method is left to «state of the art practices».

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So the studies have to do it

That is the whole argument for reading the trials themselves. Here are the five, with the size, the length and the design next to each.

Ingredient	People	Length	Design	Measured	Number
Ceramide	50	4 weeks	Single arm, no control	Hydration, TEWL	Hydration median 50 to 80
Panthenol	25 enrolled 21 finished	26 days	Randomised, double-blind, placebo-controlled	Hydration after irritation	Better on the active side in 11, placebo in 1
Colloidal oatmeal	29 women	Not reported	Investigator-blinded	Dryness, scaling, roughness, itch	All four improved
Licochalcone A	1,221	4 weeks	Open study, no control	Redness and related scores	P<0.001
Niacinamide	50 women 46 finished	4 weeks	One forearm untreated, investigator-blind	TEWL, capacitance	TEWL 2.5 vs 3.9

The last row is worth a pause. Niacinamide sits on Korea’s brightening list at 2–5%. This study measured something else entirely — barrier. The ingredient name does not tell you what was measured.

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And where each one is weak

Ingredient	Where it is weak	How to read it
Ceramide	No control group, one site, manufacturer-funded	Read what was measured, not the size of the change
Panthenol	Only one endpoint reached significance	The design is the strongest of the five
Colloidal oatmeal	The abstract does not give the duration	Read it without knowing how long
Licochalcone A	No control, and the product also contained trans-4-t-butylcyclohexanol	The two cannot be separated here
Niacinamide	The facial figures were not tested statistically	Read the forearm numbers

Of the five, one design is clearly the strongest, and it is the smallest study. Twenty-five people, randomised, double-blind, placebo-controlled, with the irritation deliberately induced. The study with 1,221 people has no control group at all. Size and strength are not the same thing, and a box never prints either.

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Four things to check on the box

✔ Look past “for sensitive skin” and check whether the five names are in the ingredient list

✔ The earlier a name sits in that list, the more of it is in there

✔ Photograph the names after “fragrance” so you can compare them later

✔ Try anything new on the inside of your arm for a few days first

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One line

No regulator in these three places names an ingredient for sensitive skin, so the studies have to. Decide first whether your issue is barrier, itch or redness, and five becomes three.

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What I left out, and why

✔ Centella asiatica and madecassoside — I could not open a human study, only reviews

✔ “Fragrance-free is safer” — no primary source for it

✔ The facial figures in the niacinamide study — cheek TEWL fell, but those values were not tested statistically

✔ Prescription drugs and procedures — they do not belong in a cosmetics piece

✔ An EU rule specific to sensitive skin — I did not find one, which is not the same as saying none exists

About the author · Dr. J

📌 Previously

📌 Niacinamide: How Much Is Enough — the same ingredient, seen from the brightening side

📌 Ceramides – cholesterol and fatty acid ratio — the first ingredient here, in full

📌 Panthenol for Skin: What the Dexpanthenol Studies Show — the irritation side

📌 How to Read a Korean Cosmetic Ingredient List — where to find these names on the box

📄 References

· Regulation on Review of Functional Cosmetics, Annex 4 (Korean Law Service, opened 2026-10-17)

· MFDS, Guideline on Test Methods for Substantiating Cosmetic Claims (2018-03, 안내서-0353-02)

· MFDS, Guideline on Cosmetic Labelling and Advertising (2025-08-14, 안내서-0086-07), Annex 2

· Draelos ZD, Raymond I. J Clin Aesthet Dermatol 2018;11(5):30-32

· Biro K, Thaçi D, Ochsendorf FR, Kaufmann R, Boehncke WH. Contact Dermatitis 2003;49(2):80-84

· Reynertson KA et al. J Drugs Dermatol 2015;14(1):43-48 · Jovanovic Z et al. ibid. 2017;16(6):605-611

· Draelos ZD, Ertel K, Berge C. Cutis 2005;76:135-141

· U.S. FDA, “Hypoallergenic Cosmetics” (content current as of 2022-02-25)

· Regulation (EC) No 1223/2009, Article 14 · Regulation (EC) No 655/2013

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This article summarises published studies and public regulatory documents. It is information, not diagnosis or treatment. Of the five studies, two had no control group and one does not report its duration, and one was run on a product containing two actives. Those limits are set out in the tables above rather than hidden. Ingredient names and concentrations are given as criteria for choosing a product, not as a recommendation of any particular one.

— Dr. J Ingredient Notes

October 17, 2026

Pores and Sebum in Korean Cosmetics: Five Ingredients, and the Test Method the Regulator Wrote Down

🇰🇷 한국어판

Hello, this is Dr. J. Today we look at the five ingredients worth knowing for oily skin and visible pores — chosen, in every case, from a human study that actually measured sebum.

Here is the surprise. In Korea, “pores” is not one of the claims the regulator has written a test method for. “Sebum secretion control” is — down to the instrument, the number of seconds and the unit.

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The primary sources

📄 MFDS, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (March 2018, PDF, Korean)

📄 Green tea, split-face study (Hippokratia 2013;17(1):64-67)

📄 L-carnitine and EGCG (J Cosmet Dermatol 2023)

📄 Regulation (EC) No 655/2013, common criteria

Chapter 3 of the Korean guideline sets out the sebum procedure itself — the device, the thirty seconds, the unit, and the two values that are measured separately.

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In five lines

✔ Korea’s functional-cosmetic notice has no pore or sebum entry

✔ Yet a separate guideline sets out how sebum is measured — chapter 3 of ten

✔ Three ingredients here have measured sebum numbers

✔ One more study measured the nose and the forehead apart

✔ What the studies measured is sebum, not pore size

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What Korea’s notified list does fix

Korea’s Regulation on Functional Cosmetic Review carries an annex that fixes ingredient names and percentages. Formulate to that line and you are excused from filing fresh efficacy data — which also means the state has drawn the boundary of each claim.

Claim	What the annex fixes	How to read it
Whitening	Nine ingredients with percentages (arbutin 2–5%, niacinamide 2–5%, and others)	Both the name and the number are set
Wrinkle improvement	Four ingredients (retinol 2,500 IU/g, adenosine 0.04%, and others)	The same
Acne-prone skin relief	One ingredient — salicylic acid 0.5%	This is where blocked pores lead
Pores and sebum	No entry at all	“Pore minimising” and “sebum control” have not been reviewed as claims

That is not a ban. It means no authority has signed off on the wording. The same gap appeared in our piece on sensitive skin — but with pores and sebum there is a second document to open.

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The claim without a method, and the claim with one

The Ministry of Food and Drug Safety publishes a separate guidance document, the Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (March 2018, guidance 0353-02). It gives each claim type its own chapter. There are ten.

Chapter	Claim	Chapter	Claim
1	Skin moisturisation	6	Dark circle improvement
2	Skin elasticity improvement	7	Skin blood circulation
3	Sebum secretion control	8	Puffiness relief
4	Temporary cellulite reduction	9	Paraben-free
5	Suitable for acne-prone skin	10	Fine-dust protection

Pores are not among the ten. The word appears once, in a footnote to chapter 5 that defines a comedo as a small sac formed when the opening of a sebaceous gland is blocked.

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What chapter 3 actually says

“A Sebumeter® is used. When the Sebumeter®, fitted with a special opaque plastic tape, is pressed on the skin with slight pressure for 30 seconds to collect sebum, the increase in the transparency of the tape is turned into a figure shown on the device, and that figure represents the amount of sebum per unit area (µg/cm²) collected.” — our translation of the Korean guideline, chapter 3

What	As the guideline sets it
Device	Sebumeter® — reads how far an opaque tape turns transparent
Time	30 seconds of slight pressure on the skin
Unit	Sebum per unit area, µg/cm²
Casual sebum level	Measured as soon as the volunteer arrives, without washing — what has pooled on the skin
Sebum excretion rate (SER)	Measured after everyone washes with the same cleanser — how fast sebum returns
Schedule	A fixed body site, measured before and after application of the test material

The split matters. “There is a lot of oil sitting there” and “oil comes back quickly” are different statements, and most of the studies below measured the second one.

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Five ingredients in one table — including where each is weak

Ingredient	Study	People · duration	Compared with	What was measured	Where it is weak
Niacinamide 2%	Draelos 2006 J Cosmet Laser Ther 8(2)	100 Japanese women · 4 weeks 30 US women · 6 weeks	Placebo	Sebum excretion rate down 21.8% (placebo 10.7%) At 2 weeks 21.3% (placebo 8.6%)	The two groups parted — the US arm did not reach significance
Green tea 5%	Mahmood 2013 Hippokratia 17(1)	22 men (22–28) · 60 days	One cheek against a placebo cheek	About 27% lower (p=0.0060) Sebumeter SM 815	22 men, and the raw µg/cm² values appear only in the figures
L-carnitine 2% EGCG 5%	Detudom 2023 J Cosmet Dermatol 22(11)	90 subjects, three arms · 4 weeks	The three active arms against each other	All three arms fell (p<0.01) The combination beat L-carnitine alone (p=0.009)	No placebo arm · age and sex are not in the abstract
Guava leaf 6%	Pongsakornpaisan 2019 J Cosmet Dermatol 18(6)	21 subjects · 28 days	Half the face against the base toner (single-blind)	Sebutape® Forehead 13.10±3.67% (P<0.05) · nose 21.43±3.21% (P<0.001) The nose parted from week three	21 subjects, and the abstract alone does not settle whether the percentages are against baseline or between arms
Salicylic acid 0.5%	Korean notice, Annex 4	—	—	The notified ingredient for acne-prone skin relief	Regulatory ground, not a sebum measurement

Read the table across and the yardstick appears. Numbers of people, duration and comparator give the same percentage a different weight.

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The one ingredient Korea fixed by notice

Item	As the notice sets it
Ingredient and level	Salicylic acid 0.5%
Form	Solution · lotion · cream
Claim	“Helps relieve acne-prone skin”
Directions	Apply an appropriate amount and rinse off thoroughly with water straight away
Age restriction Safety standards, Annex 2	0.5% as salicylic acid, not for use in products for infants or products specifically labelled as usable by children aged 13 or under (shampoo excepted)

Note the rinse-off in the directions. The form Korea reviewed is not a leave-on product. In the United States the same acid for acne is not a cosmetic ingredient at all — see the next table.

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Who writes the test method — Korea, the EU and the US

	Korea	EU	United States
List of claims	For functional cosmetics the notice fixes ingredient and percentage; other claims appear on a separate substantiation list	Not a list but six common criteria (Reg. (EC) No 655/2013)	“FDA does not have a list of approved or accepted claims for cosmetics.“
Test method	Written out claim by claim — ten chapters, chapter 3 being sebum secretion control (Sebumeter® · 30 seconds · µg/cm²)	Evidence “shall take into account state of the art practices“. The Commission’s technical document asks for “methods which are reliable and reproducible” and names no particular test	No prescribed method. Labelling, including claims, “must be truthful and not misleading“
Salicylic acid for acne	A cosmetic — notified functional ingredient at 0.5%	Handled inside the cosmetics regulation	An OTC drug — 21 CFR 333.310 sets it at 0.5 to 2 percent
Pores	Neither in the notice nor among the ten test methods	We found nothing set aside for it	The same

Put the three side by side and the axis is clear. Korea writes down what to measure and how; the EU sets a condition — reliable, reproducible, state of the art — and leaves the method to the field; the United States keeps no approved list at all. The clearest illustration is that the same salicylic acid is a cosmetic ingredient in Seoul and a drug ingredient in Washington.

For a brand selling into Korea, that has a practical edge: the procedure your sebum claim will be read against is a public document, and it is specific enough to design a study from.

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Four things to check on the box

✔ “Pore minimising” is not a reviewed claim — look for the number and the source

✔ What the studies measured is sebum, not pore diameter

✔ Check how many people and for how long — 21 and 100 are not the same weight

✔ Check whether there was a placebo arm — in one of these studies there was not

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One line

Pores have no measuring stick yet; sebum has one. Start with the side that carries numbers.

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What I did not use, and why

✔ Trials that measured pore size — none of the human cosmetic studies I opened measured pores directly

✔ Procedures — randomised trials of botulinum toxin or microneedling for pores belong to a different article

✔ Retinol and pores — I opened two retinol trials; neither abstract reported a pore endpoint, and one compared against a prescription drug

✔ Folk claims — “pores never shrink once enlarged”, “cold water closes pores”: no primary source

✔ A fresh reading of the niacinamide paper — the literature databases were rate-limited on the day of writing, so the figures come from an earlier piece in which the full text was read

About the author · Dr. J

📌 Related posts

📌 Niacinamide: How Much Is Enough (Ingredient Guide 2) — the first ingredient here

📌 Salicylic Acid (BHA): 0.5% vs 2%, Explained (Guide 8) — the notified 0.5% in full

📌 AHA vs BHA: Is Glycolic Acid an AHA? (Guide 13) — the blocked-keratin side

📌 How to Read a Korean Cosmetic Ingredient List (Guide 14) — finding the names on the pack

📄 Sources

· MFDS, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (civil-petition guidance 0353-02, March 2018), chapter 3

· Regulation on Functional Cosmetic Review, Annex 4 · Regulation on Safety Standards for Cosmetics, Annex 2

· Draelos ZD, Matsubara A, Smiles K. J Cosmet Laser Ther 2006;8(2):96-101

· Mahmood T, Akhtar N, Moldovan C. Hippokratia 2013;17(1):64-67

· Detudom P et al. J Cosmet Dermatol 2023;22(11):3058-3064 · Pongsakornpaisan P et al. ibid. 2019;18(6):1737-1741

· Regulation (EC) No 655/2013, Annex (common criteria) · European Commission, Technical document on cosmetic claims

· U.S. FDA, “Cosmetics Labeling Claims” (current as of 21 November 2022) · 21 CFR 333.310

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This article summarises published studies and regulatory documents and is not a substitute for diagnosis or treatment. The Korean legal database was unavailable on the day of writing, so the notice figures come from earlier pieces in which the originals were read, and the niacinamide paper was not reopened. Translations of the Korean guideline are mine. Ingredient names and concentrations are given as criteria for choosing a product, not as a recommendation of any particular one.

— Dr. J Ingredient Notes

October 16, 2026

Preservative Limits in Korean Cosmetics: Why Parabens Sit on One Grouped Line, and How the EU Splits It in Two (Ingredient Guide 25)

🇰🇷 국문판 (Korean version)

Hello, this is Dr. J. Today we are reading the preservative limits in Korean cosmetics — the numbers behind parabens and phenoxyethanol.

Here is the part that surprises people first. The Korean notice never uses the word “paraben.” Several parabens sit on one grouped line, and the salts ride that line too.

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The primary sources

📄 Cosmetics Act Article 8 (Korea Cosmetic Association)

📄 Annex 2, raw materials needing restricted use (Korea Law Information Center)

📄 KCIA ingredient dictionary — ethylparaben

📄 Commission Regulation (EU) No 1004/2014 · No 358/2014

📄 Parabens in Cosmetics (U.S. FDA)

Annex 2 gives each preservative a line of its own: the name, the ceiling, and the condition attached. Find the preservative on your label in that table and you can read off how much is allowed and in which kind of product.

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If you are in a hurry — five lines

✔ Preservatives work from an allowed list, the way colorants do

✔ The paraben line reads 0.4% single, 0.8% mixture (as acid)

✔ Phenoxyethanol is 1.0%

✔ The EU cuts butyl- and propylparaben to 0.14% inside the same group

✔ The United States has no rule aimed at preservatives

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Article 8 names preservatives first

Korea’s Cosmetics Act splits raw materials into two kinds. Some may never be used. Others may be used under conditions.

Paragraph	What it does	Text
Article 8 (1)	Designates the raw materials that may not be used	“The Minister of Food and Drug Safety shall designate and announce the raw materials that may not be used in the manufacture of cosmetics.”
Article 8 (2)	Sets conditions of use for preservatives, colorants and UV filters	For raw materials that need special restrictions, “such as preservatives, colorants and ultraviolet blocking agents”, the Minister shall designate and announce the conditions of use, and a preservative, colorant or UV filter whose conditions of use have not been announced may not be used.
Article 8 (5)	Reviews those conditions periodically	The Minister shall periodically review the safety of the announced conditions of use, and may change them according to the result.

Of the three named in paragraph (2) — preservatives, colorants and UV filters — preservatives come first. And the paragraph closes by barring anything outside the announced list. So a preservative in Korea works from an allowed list, not a banned one: a substance with no announced condition of use cannot go in the bottle at all.

Paragraph (5) adds one more layer. The ceilings are reviewed periodically and may be changed. That is exactly what happened in Europe, twice, to the same group of parabens — these numbers are reviewed values, not fixed ones.

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Parabens sit on one grouped line

Open the preservative table in Annex 2 and the word “paraben” is not there. This is what you find instead.

How the notice writes it	What that one line covers	Limit
“p-hydroxybenzoic acid, its salts and esters (excluding phenyl among the esters)”	The esters — methyl-, ethyl-, propyl-, butylparaben The salts — sodium methylparaben, sodium propylparaben The acid itself	0.4% (as acid) for a single ingredient 0.8% (as acid) for a mixture
What the bracket takes out	Phenyl, among the esters	Not on this line

One group name carries three things at once: the acid itself, the esters, and the salts. So when you see sodium propylparaben on a Korean label, it is not a different substance that slipped past the rule — it is the same line and the same ceiling.

The bracket takes out one ester: phenyl. Europe takes out five. That difference is the next table.

You can see the grouping for yourself in the Korea Cosmetic Association’s ingredient dictionary: open ethylparaben and sodium propylparaben separately and both carry the same notice name and the same figures.

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The rest of the preservative table — the conditions matter as much as the numbers

A preservative line is rarely a number on its own. Most of them also say which kind of product the substance may go into.

Preservative	Limit	Condition attached
p-hydroxybenzoic acid, its salts and esters (parabens)	0.4% single · 0.8% mixture	As acid · phenyl ester excluded
Phenoxyethanol	1.0%	—
Sorbic acid	0.6%	—
Benzoic acid	0.5%	2.5% in rinse-off products
Salicylic acid	0.5%	Not for products for infants, or labelled as usable by children aged 13 or under (shampoo excepted)
Benzyl alcohol	1.0%	10% as a solvent in hair dyes
Phenoxyisopropanol	1.0%	Rinse-off products only · banned in all others
CMIT / MIT mixture	0.0015%	As a 3:1 mixture · rinse-off only · banned in all others
MIT alone	0.0015%	Rinse-off only · not to be combined with the mixture above · banned in all others

Three shapes show up. A plain ceiling (phenoxyethanol, sorbic acid). A ceiling that changes with the product (benzoic acid). And a ceiling that comes with a product type attached (phenoxyisopropanol, the isothiazolinones) — for those, “rinse-off only” is the whole point of the line.

Salicylic acid carries an age condition: it is not for products for infants, or for products labelled as usable by children aged 13 or under, with shampoo excepted. That is the same rule that shapes Korea’s children’s cosmetics regime (Ingredient Guide 20).

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The EU splits the same group in two

Entry 12 of Annex V to Regulation (EC) No 1223/2009 opens with almost the same sentence as the Korean notice: “4-Hydroxybenzoic acid and its salts and esters, other than the esters of isopropyl, isobutyl, phenyl, benzyl and pentyl”. Same grouping habit, same 0,4% / 0,8%.

What differs is whether the group gets divided again.

	Korea	European Union	United States
How parabens are written	One grouped line — “p-hydroxybenzoic acid, its salts and esters (excluding phenyl among the esters)”	Two entries — Annex V 12 and 12a	No list of its own
Limit	0.4% single · 0.8% mixture (as acid)	12 keeps 0,4% / 0,8% 12a sets butyl- and propylparaben at 0,14% (as acid)	No figure set
Esters barred outright	Phenyl	Isopropyl, isobutyl, phenyl, benzyl and pentyl — five (Reg. 358/2014, applied 30 Oct 2014)	—
Age or body-area condition	None on the paraben line	12a — “Not to be used in leave-on products designed for application on the nappy area of children under three years of age” (Reg. 1004/2014, applied 16 Apr 2015)	—
Shape of the rule	A preservative needs announced conditions of use before it can be used	A preservative has to be listed in the annex	FDA — “FDA doesn’t have special rules that apply only to preservatives in cosmetics.”

Europe moved in two steps. From 30 October 2014, five esters were moved out of entry 12 and into the banned annex (Regulation 358/2014) — and that regulation states in its recitals that “measures on propylparaben and butylparaben are under preparation”. From 16 April 2015, those two were cut to 0,14% and given the nappy-area condition (Regulation 1004/2014).

The regulation also explains where 0,14% comes from. The SCCS figure was 0,19% expressed as esters; because entry 12 is written “as acid”, the Commission converted it to 0,14% as acid so the two entries could be read together. The science did not change between those numbers — the unit did.

The United States draws no such line. FDA states plainly that it “doesn’t have special rules that apply only to preservatives in cosmetics”, and that cosmetic ingredients other than color additives do not need FDA approval before going on the market.

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One substance, three ways of drawing the line

Korea	European Union	United States
Allowed list, by notice under Article 8 (2)	Allowed list, Annex V	No preservative-specific rule
Parabens grouped on one line, salts included	Same group, split into 12 and 12a	Methyl-, propyl-, butyl- and ethylparaben named as the most common, with no limit set
Conditions attach product types (rinse-off only) and ages (salicylic acid)	Conditions attach product types, body areas and ages	Safety rests on the manufacturer; FDA may act on a marketed product

This is the part worth carrying away. A Korean label and a European label can show the same preservative at the same percentage and still sit under different rules — and a U.S. label sits under none written for preservatives at all. The number on the back of the bottle does not tell you which system you are reading.

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What to check on the box

✔ Preservative names sit near the end of the ingredient list, around the 1% mark

✔ For parabens, read methyl-, ethyl-, propyl-, butyl- and the salt names such as sodium methylparaben

✔ Some ceilings apply to rinse-off products only, so check whether the product stays on the skin

✔ On products labelled for children, Korean packaging prints the preservative content as its own line

✔ A ceiling is the upper bound, not the amount in the jar — two different things

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What I left out, and why

✔ The notice number and effective date — Korea’s law portal was unreachable on the day this was written, so I could not confirm the current number of the Cosmetic Safety Standards. Only the article numbers and the annex name are given here

✔ The full Annex 2 preservative table — same reason. The figures above come from the text obtained on 20 September 2026, cross-checked in the KCIA ingredient dictionary

✔ The paraben safety debate — I did not open the review papers or the opinions themselves. What the EU changed, and what FDA says, is the range of this article

✔ The EU figure for phenoxyethanol — a secondary source gives 1.0%, but I could not obtain the annex table itself, so it is not in the comparison

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In one line

A preservative is used from a list, within the stated ceiling, in the stated kind of product. Where that line gets drawn is what changes between countries.

Next: the 25 fragrance allergens — why those names are printed separately on the box.

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📌 Related reading

📌 How to Read a Korean Cosmetic Ingredient List (Ingredient Guide 14) — where preservative names sit

📌 Salicylic Acid (BHA): 0.5% vs 2% (Ingredient Guide 8) — a preservative on the same annex

📌 Sunscreen SPF and PA (Ingredient Guide 11) — the third material named in Article 8 (2)

📌 AHA vs BHA: Is Glycolic Acid an AHA? (Ingredient Guide 13)

About the author · Dr. J

📄 Sources

· Cosmetics Act of Korea, Article 8 — paragraphs (1), (2) and (5)

· Regulation on Cosmetic Safety Standards, Annex 2 (raw materials needing restricted use), preservatives

· Korea Cosmetic Association ingredient dictionary — ethylparaben, sodium propylparaben, phenoxyisopropanol, methylisothiazolinone, methylchloroisothiazolinone

· Commission Regulation (EU) No 1004/2014 and No 358/2014 (EUR-Lex) · Regulation (EC) No 1223/2009, Annex V entry 12

· U.S. FDA, Parabens in Cosmetics (updated 18 November 2025)

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This article summarises statutes and official notices and is not a substitute for diagnosis or treatment. Korea’s law portal was unreachable on the day of writing, so the Annex 2 figures were matched against text obtained earlier and cross-checked in the Korea Cosmetic Association ingredient dictionary; the current notice number is not stated. EU and U.S. material is taken from each authority’s current public text.

— Dr. J Ingredient Notes

October 9, 2026

Children’s Cosmetics in Korea: What the Label Triggers, and Why the Box Prints a Preservative Percentage (Ingredient Guide 20)

Cover image for a guide to Korea's rules for children's cosmetics, Ingredient Guide 20 from Dr. J Ingredient Notes. Infants are three years of age and under and children are four to thirteen, and once a product says so on the label three rules follow.

🇰🇷 한국어판: 어린이 화장품 기준 – 「어린이용」이라 적으면 따라오는 것, 그리고 상자의 보존제 함량

Hello, this is Dr. J. Today I want to read Korea’s rules for children’s cosmetics straight from the statute, because one of them changes what is printed on the box.

Most countries regulate what may go into a product for a child. Korea does that too, but it adds something unusual: once a product says it is for children, the outer package has to carry the amount of preservative in it, as a number, separate from the ingredient list. I have not found that requirement anywhere else.

And the trigger is not the formula. It is the label. That is the part worth understanding first, so let me start there.

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The sources, if you would rather read them first

📄 Korea Ministry of Government Legislation — cosmetics for infants and children — the age brackets and the three documents

📄 Safety Standards for Cosmetics, Annex 2 — the entries that carry an age condition

📄 Commission Regulation (EU) No 1004/2014 — parabens and the nappy area

📄 US FDA — Summary of Cosmetics Labeling Requirements — what a US label has to carry

The Korean annexes open as attachment files, so the text comes up directly rather than through a search form.

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Five lines, if you are in a hurry

✔ Korean law splits the two groups by age — an infant is 3 and under, a child is 4 to 13

✔ The rules attach the moment the package, the product name or an advertisement says the product is for them

✔ Three safety documents must be written and kept, for a year past the expiry date or three years past the manufacturing date

✔ The outer package gains one line — the content of the preservatives, printed apart from the ingredient list

✔ Salicylic acid and iodopropynyl butylcarbamate step out of products labelled for under-13s

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Two age groups, written into the statute

Article 4-2 of the Cosmetics Act and Article 10-2 of its Enforcement Rule define the two groups by age. An infant is three years of age and under. A child is four to thirteen.

The upper bound is worth noticing. Thirteen takes in primary-school age, so a lotion or a lip balm marketed to a nine-year-old sits inside the same rules as a baby lotion. In several other markets the special category stops at three.

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The rule starts at the label, not at the formula

This is the part that surprises people. The obligations do not attach because of what is in the bottle. They attach because of what the company says about who it is for.

Where	What makes the rules attach
Packaging	The inner or outer package states, specifically, that the product may be used by an infant or a child
Product name	The name of the cosmetic itself carries a reference to infants or children — the name alone is enough
Advertising	Newspapers, broadcast, magazines, the internet, posters and signboards, video or film, stating it specifically

So a very mild formula with no such wording stays outside the rules, and an ordinary formula with the wording falls inside them. The word the statute uses is “specifically”: a vague impression that a child might use it is not the test — naming the group is.

※ This is why the phrase on the front of a Korean box is a regulatory statement rather than a marketing flourish.

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Three documents, and how long they are kept

Once that wording is used, the responsible distributor has to prepare and keep product-specific safety documentation. Enforcement Rule Article 10-3 lists three items and sets the retention period.

Document	Content	Kept until
① Product and method	A description of the product and of how it is manufactured	Products labelled with an expiry date — one year after the expiry date of the last batch made or imported Products labelled with a period after opening — three years after the manufacturing date of the last batch
② Safety assessment	A safety assessment of the cosmetic product
③ Evidence of effect	Evidence for the efficacy or effect claimed for the product

The retention clock keeps running after the product has left the shelves — a year past the expiry date of the final batch. Failure to prepare or keep the documents carries up to one year of imprisonment or a fine of up to ten million won, and a company can be fined alongside the individual.

※ A shopper cannot ask to see this file. What is useful to know is that the phrase “for children” on a Korean box has a dossier sitting behind it.

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One extra line on the box — the preservative content

Here is the part a shopper can actually see. Where a product is labelled or advertised specifically for infants or children, the outer package must carry “the content of preservatives among the raw materials whose standards of use are designated and published”.

Compare that with the ordinary ingredient list. Ingredients are listed in order of how much is present, and in Korea anything at or below 1% may be listed in any order. No amounts appear. On a children’s product, the preservatives come back with a number attached — “phenoxyethanol 0.4%”, printed in its own line.

Two things follow from that line. First, its presence tells you the product is formally labelled for children. Second, it tells you which preservative is in there and how much. If no preservative is used, there is nothing to declare and the line is simply absent.

※ The basis is Article 10 of the Act with Article 19 of the Enforcement Rule. Look for it beside the ingredient list, not inside it.

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Two ingredients that step out

Annex 2 of the Safety Standards for Cosmetics sets a maximum for each restricted raw material. Two of those entries carry an age condition, and I opened both.

Ingredient	Limit	Age condition
Salicylic acid and its salts	0.5% as salicylic acid	Not to be used in products for infants, or in products labelled specifically as usable by children aged 13 or under (shampoo excepted)
Iodopropynyl butylcarbamate (IPBC)	0.02% rinse-off · 0.01% leave-on · 0.0075% in deodorants	The same prohibition (bath products, shower gels and shampoos excepted)

Read the two columns together. 0.5% is the adult ceiling; in a children’s product the ingredient is not permitted at all, not permitted at a lower level. The exceptions in brackets follow the same logic in reverse — products that are rinsed off are treated differently from products that stay on the skin.

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Fragrance allergens: 25 names, the same thresholds

If a Korean ingredient list ends with limonene, linalool, citronellol and a few more, those are the fragrance allergens that must be named separately rather than hidden inside “fragrance”. There are 25 of them.

The thresholds are above 0.01% in rinse-off products and above 0.001% in leave-on products. They are not lowered for children’s products — the annex carries no age clause at all.

※ A long tail of names is disclosure, not concealment. For a child who reacts to fragrance, that tail is the part of the label worth reading.

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Korea, the EU and the US, side by side

Three regulators, three different places to put the line. Korea hangs its rules on the label, the EU writes age into individual ingredient entries, and the US asks for no amounts on the label at all.

Where	What applies to a children’s product	Source
Korea	Infant 3 and under, child 4 to 13. Label or advertise it as such and three safety documents follow, plus the preservative content printed on the package	Cosmetics Act Art. 4-2, Art. 10 Enforcement Rule Art. 10-2, 10-3, 19
European Union	Propylparaben and butylparaben capped at 0.14% as the sum (as acid), and “not to be used in leave-on products designed for application on the nappy area of children under three years of age”; such products carry “Do not use on the nappy area”	Reg. (EU) No 1004/2014 Annex V entry 12a, applying from 16 April 2015
United States	“The ingredients must be declared in descending order of predominance”, and “color additives and ingredients present at one percent or less may be declared without regard for predominance”. No amount has to be shown	US FDA, Summary of Cosmetics Labeling Requirements

The contrast worth taking away is the middle column of the first row. A Korean children’s box tells you how much preservative is in the product. A European or American one does not, however carefully it is labelled otherwise.

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What to check on the box

✔ Does the package say, in so many words, that it is for children? That is what puts it inside these rules

✔ Is there a preservative line separate from the ingredient list, and which preservative is named

✔ If salicylic acid appears, is the product one that gets rinsed off

✔ For a child who reacts to scent, read the names after “fragrance”

✔ Is the expiry date on the container itself, which survives after the box is thrown away

※ A printed line is easier to verify than a claim such as “no preservatives”. Choose on what is written.

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What I left out, and why

✔ Whether Korea restricts parabens by age. The EU does. In the extract of Annex 2 I was able to open, the paraben entries carried no age condition — but I could not confirm the full entry, so I am not claiming Korea has no such rule

✔ The sub-paragraph numbers for the preservative-content requirement. Different official sources number it differently, so I cite the Act’s Article 10 with Article 19 of the Enforcement Rule and stop there

✔ “Baby products should be fragrance-free and preservative-free.” There is no primary source for that as a rule, and removing preservatives moves the microbiological question elsewhere rather than removing it

✔ Product names. This blog does not recommend particular products

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In one line

In Korea, the rules for a children’s cosmetic begin with the words on the label, not with the formula inside. Say it, and a dossier follows — and the box gains a line telling you how much preservative is in there.

Next in this series: what a “vegan” claim on a cosmetic certifies, which in Korea runs through an industry self-review rather than a government mark — a companion to the organic and natural guide (Ingredient Guide 21).

📌 Earlier guides

📌 How to Read a Korean Cosmetic Ingredient List (Guide 14)

📌 Salicylic Acid (BHA): 0.5% vs 2%, Explained (Guide 8)

📌 Ceramides: the Cholesterol and Fatty Acid Ratio (Guide 4)

📌 Niacinamide: How Much Is Enough (Guide 2)

About the author · Dr. J

📄 References

· Cosmetics Act of Korea, Articles 4-2 and 10

· Enforcement Rule of the Cosmetics Act, Articles 10-2, 10-3 and 19

· Safety Standards for Cosmetics, Annex 2 (restricted raw materials)

· Notification on precautions and fragrance allergen labelling, Annex 2 (25 substances)

· Commission Regulation (EU) No 1004/2014, Annex Ⅴ entry 12a

· U.S. FDA, Summary of Cosmetics Labeling Requirements

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This article summarises public statutes and regulatory documents and is not a substitute for diagnosis or treatment. Quoted sentences are as they appear in the law and the notifications, and labelling practice varies between products. If a child’s skin reacts, stop using the product and speak to a professional.

— Dr. J Ingredient Notes

October 1, 2026

Cosmetic Expiration Dates in Korea: What 12M Means and Why a Jar Carries Two Dates (Ingredient Guide 17)

Cover image for a guide to cosmetic expiration dates and the 12M period-after-opening symbol in Korea, Ingredient Guide 17 from Dr. J Ingredient Notes, explaining why a Korean jar carries two dates.

🇰🇷 한국어판: 화장품 사용기한과 개봉 후 사용기간 – 통에 적힌 날짜 두 개, 그리고 12M의 뜻

Hello, this is Dr. J. Today we are reading the dates printed on a cosmetic package — the expiration date, the period after opening, and the little open-jar symbol with 12M next to it.

Here is the part that surprises people who compare labels across countries. Korea requires one of those dates on every cosmetic, on the jar itself as well as on the box. The EU asks for a date too, with its own switch at 30 months. And in the United States, by the FDA’s own words, no law requires an expiration date on a cosmetic at all. Same product, three different labels.

So this guide does two things: it reads the Korean rule line by line, and it puts the three regimes in one table at the end.

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Primary sources

📄 Enforcement Rule of the Cosmetics Act, Annex 4 — Labelling standards and methods for cosmetic packaging (Korean)

📄 Regulation (EC) No 1223/2009, Article 19 — Labelling

📄 U.S. FDA — Shelf Life and Expiration Dating of Cosmetics

📄 21 CFR 211.137 — Expiration dating (for drug products, including U.S. sunscreens)

The Korean annex opens as an attachment file, and it spells out which words have to sit next to the numbers. That is the part almost no English-language guide quotes.

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The short version, in five lines

✔ Korean law defines the expiration date as a minimum period, not a cliff edge

✔ The box carries ten items; the jar itself carries four, and a date is one of them

✔ If a product shows a period after opening, the manufacturing date must sit beside it

✔ 12M comes from the EU rule, which switches to the open-jar symbol above 30 months

✔ The United States requires neither — shelf life there is the manufacturer’s responsibility

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What the law calls it — a “minimum period”

Article 2(5) of Korea’s Cosmetics Act defines the term. In our translation of the Korean text, an expiration date is the minimum period, counted from the date of manufacture, during which the product — stored under appropriate conditions — keeps its own characteristics and can be used safely by the consumer.

Two words in that sentence do the work.

Minimum. The date is a floor, not a ceiling. It is the point the manufacturer has tested to and will stand behind, which is a different statement from “unusable on the next day”.

Appropriate conditions. The promise is conditional, and the condition is written into the definition itself. A jar that spent a July in a parked car has left the premise the date was built on. That is why storage belongs in the same thought as the number.

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Two layers of packaging, two lists

Korean law separates the inner container — the jar, tube or bottle the product actually touches — from the outer packaging that holds it. Each carries its own list.

Where	What must appear	Source
Outer packaging the box	1. Product name 2. Name and address of the responsible business 3. All ingredients used 4. Volume or weight 5. Batch number 6. Expiration date or period after opening 7. Price 8. Functional-cosmetic marking 9. Precautions for use 10. Other items set by Presidential Decree	Cosmetics Act Art. 10(1)
Inner container the jar itself	1. Product name 2. Name of the responsible business 3. Batch number 4. Expiration date or period after opening with the manufacturing date when the period after opening is used	Cosmetics Act Art. 10(2) · Enforcement Rule Art. 19(6)

The practical consequence sits in the second row. Throw the box away and the date is still with you. The ingredient list and the price go out with the carton; the name, the company, the batch number and the date stay on the jar by law.

If you cannot find a date on a Korean product, turn the jar over. It is usually on the base or crimped into the seam of a tube, and it can be faint on dark packaging.

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How the dates must be written — Annex 4, items 5 and 6

The annex does not stop at “put a date on it”. It fixes the wording. Translated from the Korean text:

✔ Expiration date — the words “expiration date” or “until”, together with a year, month and day, written so a consumer can read it easily

✔ If only a year and month are given, they must not run past the actual expiration date

✔ Period after opening — the words “period after opening” plus “NN months”, or a symbol together with the period

✔ The batch number must be easy to tell apart from the date, and where a period after opening is used, the manufacturing date printed alongside it must also be distinguishable

That last clause is the key to the whole article. A product labelled with a period after opening carries a manufacturing date as well. If you have ever wondered why a Korean jar shows two dates, this is the reason — and the rule even says they have to be told apart at a glance.

The year-and-month clause is worth keeping too. A product good until 12 March 2027 may be printed as 2027.03, but not as 2027.04. A shortened date rounds down, never up.

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Three dates, side by side

The numbers on the back are answering different questions. Put them in one table and they stop competing.

Which date	What it states	Counted from	When it appears
Manufacturing date	the day it was made	—	alongside a period after opening
Expiration date	the minimum period of safe use	the date of manufacture	on its own; no manufacturing date needed
Period after opening	how long it keeps once opened	the day you opened it	as “NN months”, or as the symbol

The third row is where the symbol earns its keep — and where it fails. 12M runs from the day you opened the jar, not from the day it was made. Nobody but you knows that day, so the number only works if you record it.

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Where 12M comes from — the EU’s 30-month switch

The open-jar drawing with 12M beside it comes from European law. Article 19 of Regulation (EC) No 1223/2009 asks for a date of minimum durability, and then says that where that durability is more than 30 months, the label instead gives the period for which the product is safe to use after opening, shown with the symbol in Annex VII followed by the time in months or years.

Read that backwards and the symbol says something reassuring. A jar marked 12M is a product judged to last more than 30 months unopened. The 12 is about what happens after you break the seal, not a short shelf life.

Korea permits the same symbol, which is why you see it on Korean packaging as well. The difference is that Korea makes one of the two compulsory and ties the period after opening to a manufacturing date; the EU treats the two as alternatives decided by that 30-month line.

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Korea, the EU and the United States in one table

Where	What the label must carry	Source
Korea	An expiration date or a period after opening, always — on the box and on the jar. Choosing the period after opening adds the manufacturing date	Cosmetics Act Art. 10 · Enforcement Rule Annex 4
European Union	A date of minimum durability; above 30 months, the period after opening with the Annex VII symbol instead	Regulation (EC) No 1223/2009, Art. 19
United States	Neither. “There are no U.S. laws or regulations that require cosmetics to have specific shelf lives or have expiration dates on their labels.” Sunscreen, however, is an OTC drug there	FDA · 21 CFR 211.137

The FDA page does not leave it at “not required”. It adds that “FDA considers determining a product’s shelf life to be part of the manufacturer’s responsibility”. The obligation exists; what differs is whether the answer has to be printed where a shopper can read it. Korea and the EU say yes. The United States leaves it to the company.

One more wrinkle for anyone comparing sunscreens across borders. In the United States a sunscreen is regulated as an over-the-counter drug, and 21 CFR 211.137(a) requires a drug product to “bear an expiration date determined by appropriate stability testing”. So the same bottle can arrive dated in one market and undated in another — because of how the product is classified, not because of what is inside it. We read the SPF and PA numbers on those labels in Guide 11.

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What I left out, and why

✔ The test schedule behind the months — Korea’s MFDS publishes a stability-testing guideline covering long-term, accelerated and stress testing, but I could not open the document itself, so no durations or intervals are quoted here

✔ “Throw it out N months after opening” — the regulations set how the period is written, not a fixed number per product type

✔ Reading a manufacturing date out of a batch code — the coding is each company’s own, so there is nothing general to teach

✔ Mascara advice — the FDA page notes that manufacturers usually suggest replacing mascara after a few months; that is a manufacturer recommendation, not a rule, and I have left it as such

✔ Claims about what happens chemically after the date — that needs product-level data I do not have

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Five things to check

✔ Is there a date on the jar itself, not just the box

✔ If there are two, which one is the manufacturing date — it travels with a period after opening

✔ Does the open-jar symbol say 6M or 12M, and is the clock started from your opening day

✔ If only a year and month are printed, treat the end of that month as the line

✔ Is the product stored somewhere close to “appropriate conditions” — a drawer beats a bathroom shelf

I read these dates less as “use it by then” and more as “start counting here”. The manufacturing date marks the making, 12M marks the opening, and the expiration date is a separate finish line. Three clocks, three starting points.

Which leaves one habit worth building: write the opening date on the base of the jar. On a product labelled 12M, that small sticker is what turns the symbol into a number you can actually use.

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In one line

The date on a Korean jar is a minimum period, and a product labelled with a period after opening carries a manufacturing date beside it. Check the jar before the box, and write down the day you opened it.

Next in this series: the five ingredients to look for in acne-prone skin, starting with the 0.5% salicylic acid that Korea’s notification fixes in place.

📌 Related guides

📌 How to Read a Korean Cosmetic Ingredient List (Guide 14)

📌 Sunscreen SPF and PA: How to Read the Numbers (Guide 11)

📌 Arbutin vs Alpha-Arbutin: What Korea’s 2–5% Means (Guide 15)

📌 Ceramides: Cholesterol and Fatty Acid Ratio (Guide 4)

About the author · Dr. J

📄 References

· Cosmetics Act (Korea), Articles 2(5) and 10 — definitions and labelling

· Enforcement Rule of the Cosmetics Act, Article 19 and Annex 4 — labelling standards and methods

· Regulation (EC) No 1223/2009, Article 19 and Annex VII

· U.S. FDA, Shelf Life and Expiration Dating of Cosmetics (page updated 25 February 2022)

· 21 CFR 211.137 — Expiration dating

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This article summarises public regulations. It is information, not a diagnosis or a treatment plan. Quoted passages are as written in each source, translations from the Korean text are ours, and labelling practice varies from product to product. If a product looks or smells changed, stop using it and speak with a professional.

— Dr. J Ingredient Notes

September 30, 2026

Acne Skincare Ingredients: What Korea’s 0.5% Salicylic Acid Rule Means, and Four Ingredients with Human Trials

Cover image for an article on acne skincare ingredients. It covers the one ingredient Korea's functional cosmetics notice lists for acne, salicylic acid at 0.5 percent, and four more ingredients with human trials: glycolic acid, niacinamide, tea tree oil and green tea EGCG.

🇰🇷 한국어판: 여드름 화장품 성분 다섯 – 고시가 정한 0.5%와 사람 대상 연구 네 편

Hello, this is Dr. J. Today we look at acne skincare ingredients — and only at what a regulation or a human trial actually says about them.

An acne aisle in Korea will show you twenty ingredient names. Exactly one of them is listed in the country’s functional cosmetics notice for acne. For the other four in this article, I opened the trials one by one.

This is also a good article for reading a Korean label from outside Korea, because the Korean rule and the American rule treat the same molecule in two different ways. Salicylic acid is a cosmetic ingredient here and an over-the-counter drug there, and the concentration ranges are different too. There is a table for that below.

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📄 The sources, first

📄 Korea — Functional Cosmetics Review notice, Annex 4 (the acne row is here)

📄 Korea — Cosmetic Safety Standard, Annex 2 (restricted raw materials)

📄 United States — 21 CFR 333.310, acne active ingredients

📄 Abels 2011 — glycolic acid 10% cream, 120 people, 90 days

📄 Draelos 2006 — niacinamide 2% and facial sebum production

📄 Enshaieh 2007 — tea tree oil 5% gel, 60 people, 45 days

📄 Yoon 2013 — green tea EGCG, 35 people, 8 weeks, split-face

The two Korean annexes download as plain text from those links, with the dosage form and the wash-off instruction written out line by line.

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In a hurry? Five lines

✔ Korea lists one acne ingredient: salicylic acid at 0.5%

✔ That product is rinsed off right after use, by the notice’s own wording

✔ The United States treats the same acid as an OTC drug at 0.5 to 2%

✔ For leave-on cosmetics, glycolic acid has a 90-day placebo-controlled trial

✔ Niacinamide was measured on sebum, not lesions, and two studies split

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Five ingredients in one table, with what each was compared against

Ingredient	Source	People · length	Compared with	What was found
Salicylic acid 0.5% rinse-off	Korean notice, Annex 4	—	Not a trial — a notice	The one ingredient listed for acne-prone skin
Glycolic acid (AHA) 10%	Abels 2011	120 enrolled, 115 analysed · 90 days	Placebo cream, double-blind	Split from placebo from day 45; adverse events alike
Niacinamide 2%	Draelos 2006	Japan 100, 4 weeks / US 30, 6 weeks	Placebo moisturizer	Japan: sebum rate down 21.8% (placebo 10.7%). US: no significant difference
Tea tree oil 5%	Enshaieh 2007	60 people · 45 days	Placebo gel, double-blind	Total lesion count 3.55x placebo; severity index 5.75x
Green tea EGCG 1% / 5%	Yoon 2013	35 finished · 8 weeks	The other half of the same face (3% ethanol vehicle)	Inflammatory lesions 10.0 to 1.1 in the 1% group

The column worth reading twice is «compared with». Two products can both say «improved» and mean very different things, depending on what sat on the other side of the comparison.

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Korea and the United States: the same acid, two systems

	Korea	United States
What salicylic acid is for acne	A functional cosmetic ingredient	An OTC drug active ingredient
Where it is written	Functional Cosmetics Review notice, Annex 4	21 CFR 333.310, acne monograph
Concentration	0.5%, one figure	0.5 to 2%, a range
How it is used	Applied, then rinsed off right away	Leave-on products are covered too
Wording on the pack	「Helps relieve acne-prone skin」	Drug Facts label, «for the treatment of acne»
Other listed actives	None for acne	Benzoyl peroxide 2.5–10%, sulfur 3–10%, resorcinol 2% with sulfur

This is the part that surprises people who read Korean labels from abroad. In Korea, a product that carries the acne functional cosmetic claim is, by the notice’s own wording, a product you wash off right away — which is why so many of them are cleansers. In the United States, the same molecule sits in 21 CFR 333.310 as an acne drug active, at 0.5 to 2 percent, and leave-on products are ordinary there.

So «Korean acne cleanser with 0.5% salicylic acid» and «American 2% BHA leave-on» are not the same category of product wearing different labels. They are two regulatory systems that decided to file the same ingredient in different drawers.

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What Korea’s notice actually says

Annex 4 of the Functional Cosmetics Review notice is a list of the cases where a company does not have to submit new efficacy data. Whitening has nine ingredients on that list, wrinkle improvement has four, and acne has one:

✔ Ingredient and amount — salicylic acid 0.5%

✔ Dosage forms — solution, lotion, cream

✔ Claim — «helps relieve acne-prone skin»

✔ Directions — «take an appropriate amount, apply to the skin, then rinse off with water right away»

There is a second Korean line worth knowing, in the Cosmetic Safety Standard, Annex 2: salicylic acid is capped at 0.5% and may not be used in products for infants, or in products labelled as suitable for children aged 13 or under — shampoos excepted. If you are buying for a younger teenager, that is the line to check.

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A leave-on option with a trial behind it: glycolic acid 10%, 90 days

Abels and colleagues, 2011. 120 people with mild acne (Leeds 0.25–1, mean age 21±5.8) were randomised; 115 made the final analysis. They applied a 10% glycolic acid oil-in-water emulsion once every evening for 90 days, as monotherapy, with cleansing standardised.

The treated group separated from placebo from day 45 at the 5% significance level, and the difference held to day 90. Adverse events did not differ significantly between the groups.

Two things are useful here. First, this is a cream you leave on, not a peel — I keep peeling and dermabrasion studies out of cosmetic articles. Second, day 45 is a reasonable answer to «how long before I judge it». Two weeks is not.

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Niacinamide 2%: read what it actually measured

Draelos, Matsubara and Smiles, 2006, ran two studies in two countries. In Japan, 100 women over 4 weeks: the sebum excretion rate fell 21.8% against 10.7% for placebo (at 2 weeks, 21.3% against 8.6%).

In the United States, 30 Caucasian women over 6 weeks: casual sebum levels trended down but only reached p=0.055, and the sebum excretion rate did not reach statistical significance.

«Niacinamide reduces oil» is repeated everywhere. The paper says two more things that rarely travel with it: it measured sebum output rather than acne lesions, and the two populations did not agree. Both belong in the sentence.

Why not a niacinamide acne trial instead? Because most of them compare it with clindamycin gel, a prescription antibiotic. I do not line cosmetics up against prescription drugs in these articles, so I used the sebum study and said so.

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Two with placebo-controlled trials: tea tree oil and green tea

Tea tree: Enshaieh and colleagues, 2007. 60 people with mild to moderate acne, randomised double-blind, 30 per group, 45 days with checks every 15 days. Improvement in total lesion count was 3.55 times that of placebo, and in the acne severity index 5.75 times. Side effects were comparable and tolerable in both groups.

Green tea: Yoon and colleagues, 2013. Thirty-seven enrolled, 35 finished 8 weeks. A randomly allocated half of each face received 1% (17 people) or 5% (18 people) EGCG solution twice daily; the other half received the vehicle, 3% ethanol only.

In the 1% group, inflammatory lesions went from 10.0±3.1 to 1.1±0.5 and non-inflammatory lesions from 53.8±19.8 to 15.6±6.2. A split-face design removes a great deal of person-to-person noise, which is what makes a 35-person study worth reading.

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How to read «it improved»

Compared with	How to read it	In this article
The same product minus the ingredient	Only that ingredient is left to explain the difference — the cleanest comparison	Glycolic acid, tea tree, niacinamide
The other half of the same face	Everything that differs between people is held still; the two halves can still influence each other	Green tea EGCG
The starting point (before and after)	The season and the person’s routine move too, so this alone is weak	Where an abstract gives no placebo figure
A notice	Not the size of an effect — the right to make a claim	Salicylic acid 0.5%

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What I left out, and why

✔ Trials against prescription drugs — most niacinamide acne trials compare it with clindamycin gel. A cosmetic article should not be read as putting a cream next to a prescription

✔ Peels and dermabrasion — salicylic and glycolic acid both have large peel literatures. That is a procedure, not a product on a shelf

✔ Bakuchiol — there is an acne study, but I could not confirm from the source whether it was placebo-controlled, so it waits

✔ Mechanism — how salicylic acid loosens keratin, or what EGCG does inside a cell, needs review articles I could not open today

Writing down what was left out is the point of the exercise: it shows you the rule I used, so you can apply the same rule to the next ingredient someone recommends.

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So where do you look?

✔ Breakouts often — start from a rinse-off product with salicylic acid 0.5%

✔ You want something you leave on — glycolic acid, and give it 45 days

✔ Oiliness is the complaint — niacinamide, knowing it was measured on sebum

✔ You want the gentler end — tea tree and green tea both have placebo-controlled trials

✔ Buying for a young teenager — check the Annex 2 age line

✔ Do not stack all five at once — one at a time, in the evening

I read the claim and the trial as two separate things. A functional cosmetic claim in Korea means a listed ingredient at a listed amount; it does not tell you the size of the effect. What comes next is whether that ingredient has a human trial, and what sat on the other side of the comparison.

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One line

Korea lists exactly one acne ingredient — salicylic acid 0.5%, rinsed off — and the other four earn their place from placebo-controlled trials. Read the claim and the trial side by side.

Next: five ingredients for dark spots, starting from the nine on Korea’s whitening list.

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📌 Previously

📌 Salicylic Acid (BHA): 0.5% vs 2%, Explained

📌 AHA vs BHA: Is Glycolic Acid an AHA?

📌 Niacinamide: How Much Is Enough

📌 How to Read a Korean Cosmetic Ingredient List

📌 Skin Concern Ingredient Map

About the author · Dr. J

📄 References

· Korea MFDS, Regulation on the Review of Functional Cosmetics, Annex 4

· Korea MFDS, Regulation on Safety Standards for Cosmetics, Annex 2

· 21 CFR 333.310 — Acne active ingredients (US FDA OTC monograph)

· Abels C, Kaszuba A, Michalak I et al., J Cosmet Dermatol 2011;10(3):202-209

· Draelos ZD, Matsubara A, Smiles K, J Cosmet Laser Ther 2006;8(2):96-101

· Enshaieh S, Jooya A, Siadat AH et al., Indian J Dermatol Venereol Leprol 2007;73(1):22-25

· Yoon JY, Kwon HH, Min SU et al., J Invest Dermatol 2013;133(2):429-440

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This article summarises published regulations and research for information only; it does not replace diagnosis or treatment. If a skin problem persists, please see a professional.

— Dr. J Ingredient Notes

September 29, 2026

Korea’s Nine Approved Brightening Actives: What the Human Studies Show for Melasma and Dark Spots

Cover image for an article on the five ingredients to look for in melasma and dark spot care. Korea's functional cosmetics notification lists nine approved brightening actives with set concentrations, and this article reads the human studies for niacinamide, arbutin, magnesium ascorbyl phosphate and alpha-bisabolol, from Dr. J Ingredient Notes.

🇰🇷 한국어판: 기미 화장품 성분 다섯 – 미백 고시 아홉 가지에서 고르는 법

Hello, this is Dr. J. Today we are choosing brightening ingredients for melasma and dark spots the way a formulator does: from the regulation first, then from the human studies.

Here is the part that surprises people outside Korea. In Korea, “brightening” is not a free marketing word. It is a functional claim, and there is an official list of actives with the amounts written next to them. The list has nine entries. I read the human evidence for each one, and I could open full abstracts for four. I will say that plainly as we go.

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Primary sources

📄 Regulation on Review of Functional Cosmetics, Annex 4 (MFDS notification) — the nine actives, their amounts, dosage forms and claim wording

📄 Niacinamide and cutaneous pigmentation (Hakozaki 2002)

📄 Arbutin 2.51% cream, 8 weeks (Morag 2015)

📄 Magnesium ascorbyl phosphate and melanogenesis (Kameyama 1996)

📄 Alpha-bisabolol in Asian women (Lee 2010)

📄 EU SCCS opinion on alpha-arbutin and beta-arbutin (SCCS/1642/22, 31 January 2023)

The Korean annex opens directly as an attachment file. It is worth opening once: the amounts are printed in a single line each, so you can hold the page next to a product’s back label.

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In short, five lines

✔ Korea’s functional list has nine brightening actives, with the amounts fixed

✔ I could open full human-study abstracts for four of them

✔ Niacinamide separated from vehicle at 4 weeks, arbutin at 8 weeks

✔ The alpha-bisabolol trial was run on the back, not the face

✔ Tranexamic acid is not on the list, and its topical trials run 12 weeks

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Nine actives, and what the amounts actually mean

The annex is titled “Types of functional cosmetics for which data submission is omitted”. Read that title before you read the numbers. The concentrations are not upper safety limits. They are the amounts at which a company does not have to submit new efficacy data, because the authority has already accepted the evidence for that active at that amount.

No.	Active	Amount	Study opened here
1	Broussonetia (mulberry) extract	2%	—
2	Arbutin	2–5%	Morag 2015 · 102 women, 8 weeks
3	Ethyl ascorbyl ether	1–2%	—
4	Oil-soluble licorice extract	0.05%	—
5	Ascorbyl glucoside	2%	—
6	Magnesium ascorbyl phosphate	3%	Kameyama 1996 · 19 of 34
7	Niacinamide	2–5%	Hakozaki 2002 · 18 and 120 people
8	Alpha-bisabolol	0.5%	Lee 2010 · 28 women, 8 weeks
9	Ascorbyl tetraisopalmitate	2%	—

The annex also fixes the dosage forms — lotion, liquid, cream and sheet mask — and the exact claim wording, which translates as “helps brighten the skin”. Even the directions are written down: apply an appropriate amount and spread evenly, and for a sheet mask, remove the sheet after 10 to 20 minutes and spread what is left. A product that follows all of this files a report instead of a full review.

The five rows marked “—” are the ones where I could not open a human study abstract today. That is not the same as saying no study exists. It is a note about what I verified, and I would rather write it than leave you guessing.

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The four, in one table — including what each was compared with

A percentage means very little on its own. What it was measured against is where the value sits: the same cream without the active, a different product, untreated skin, or simply the starting point.

Active	Study	People · duration	Compared with	What was found
Niacinamide 5%	Hakozaki et al. 2002	18 with hyperpigmentation	vehicle moisturiser, paired on the same person	Significant drop in pigmentation and rise in lightness at 4 weeks
Niacinamide 2% with sunscreen	same paper	120 with facial tanning	vehicle, sunscreen alone	Better than vehicle on skin colour measures
Arbutin 2.51%	Morag et al. 2015	102 women · 8 weeks 54 active · 48 placebo	placebo cream, double-blind	Lightening in 75.86% of melasma, 56.00% of solar lentigo placebo figures not in the abstract
Magnesium ascorbyl phosphate	Kameyama et al. 1996	34 with pigmentation duration not in the abstract	baseline pigmentation	19 of 34 improved significantly · 3 of 25 with normal skin
Alpha-bisabolol concentration not in the abstract	Lee et al. 2010	28 women · 8 weeks · back	vehicle cream on the same women	Significant lightening in most subjects
Tranexamic acid not on the list	covered in guide 9	trials run 12 weeks	varies by trial	Topical-only results were not statistically clear

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Niacinamide 2–5% — the point where it separated from vehicle was 4 weeks

Hakozaki 2002 carried two human trials in one paper. In the first, 18 people with facial hyperpigmentation used a 5% niacinamide moisturiser and a vehicle moisturiser in a paired design — both products on the same face, one per side. In the second, 120 people with facial tanning were each assigned two of three treatments: vehicle, sunscreen, or 2% niacinamide plus sunscreen.

Changes were quantified by computer analysis of high-resolution facial images and by visual grading. After 4 weeks, niacinamide significantly decreased hyperpigmentation and increased skin lightness compared with vehicle alone. The paired design is the part I like: season, sleep and sun exposure are held constant because both sides belong to the same person.

The same paper ran cell work. Niacinamide gave 35–68% inhibition of melanosome transfer in a keratinocyte and melanocyte co-culture, and reduced pigmentation in a reconstructed epidermis model. It had no effect on mushroom tyrosinase activity or on melanin production in cultured melanocytes. Worth keeping those in their own lane: a co-culture is not a face, and I would not carry the 35–68% figure over to what happens on your cheek.

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Arbutin 2–5% — 102 women, 8 weeks, and a different number in the EU

Morag 2015 was a double-blind, placebo-controlled randomised trial in 102 women aged 26 to 55 with melasma or solar lentigo. Fifty-four used a cream containing 2.51% arbutin twice daily for 8 weeks; 48 used placebo.

Lightening was seen in 75.86% of the melasma cases and 56.00% of the solar lentigo cases. The placebo-arm figures are not given in the abstract, so I have not carried them over. Read the percentage as “how many in the active arm showed lightening”, not as “how much better than placebo”.

Europe looked at the same molecule from the safety side, which is a different question from efficacy. The SCCS adopted its opinion on 31 January 2023.

What the number decides	Korea · Annex 4	EU · SCCS/1642/22 (2023)
Nature of the figure	efficacy data can be omitted	safety assessment
Arbutin (beta)	2–5%	safe in face creams up to 7%
Alpha-arbutin	not named in the annex	safe in face creams up to 2%, body lotions up to 0.5%
Hydroquinone content	not the subject of this annex	“as low as possible… not higher than the unavoidable traces in both arbutins” LOQ 3 ppm · LOD 1 ppm

So a Korean product and a European product can both be correct and still print different percentages, because the two numbers answer different questions. And on a back label, “arbutin” and “alpha-arbutin” are two different names — the annex lists the first one. Guide 15 goes through that comparison in detail.

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Vitamin C derivatives — 19 of 34, and only 3 of 25

Four of the nine entries are vitamin C derivatives: ethyl ascorbyl ether 1–2%, ascorbyl glucoside 2%, magnesium ascorbyl phosphate 3% and ascorbyl tetraisopalmitate 2%. Pure ascorbic acid is unstable in a finished formula, so the molecule is modified and the skin’s enzymes are expected to release it.

Of those four, the one I could open was magnesium ascorbyl phosphate. Kameyama 1996 reported that 19 of 34 patients with chloasma or senile freckles showed significant lightening. In the same paper, among 25 people with normal skin, only 3 did.

Put those two numbers side by side and you get a way to read them: this is an ingredient that earns its place where the pigment already is. Expect it to work on the dark patch rather than to change your overall complexion. The trial duration is not stated in the abstract, which is worth knowing before you set a deadline for it.

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Alpha-bisabolol 0.5% — the trial was not run on faces

Lee 2010 tested a base cream containing alpha-bisabolol on 28 female subjects, applied once a day for 8 weeks. The application site was pigmented skin on the back, and the same women also applied a vehicle control cream. Results were assessed by clinical and biophysical methods, and after 8 weeks most subjects showed significant lightening.

Two honest notes. The concentration of alpha-bisabolol in the cream is not given in the abstract, and the back is not the face: thicker stratum corneum, different sun exposure, different pigment history. The annex figure of 0.5% is what Korea accepted for the claim; the trial figure is simply not stated. Knowing that keeps the expectation the right size.

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The one that is not on the list — tranexamic acid

Tranexamic acid does not appear among the nine. A Korean product carrying the brightening claim with tranexamic acid has therefore been through an individual review with its own safety and efficacy dossier, rather than the report route that the listed actives allow.

The trials are built around 12 weeks, and when the topical route is pooled on its own the result was not statistically clear. Guide 9 sets out those numbers, including the confidence interval, and it is the honest place to start if a tranexamic acid serum is already in your routine.

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What is not in this article, and why

✔ Comparisons with hydroquinone or prescription creams — a cosmetics article should not line itself up against a drug

✔ Laser and chemical peel trials — procedures are a separate conversation from ingredients

✔ Retinol for pigmentation (Kafi 2007) — I opened the abstract and it reports fine wrinkles and collagen markers, with no pigmentation outcome, so it is out

✔ Mechanism paragraphs — where I could not open the review, I stopped at what the abstract itself states

✔ Claims that circulate online — “vitamin C erases melasma”, “use brighteners at night only” — no primary source, so no sentence

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Four things to check when you buy

✔ Whether the carton carries the functional cosmetics mark, with the claim wording printed underneath in the same size or larger

✔ Which of the nine names appears in the ingredient list

✔ Whether the format is a lotion, liquid, cream or sheet mask

✔ Whether there is enough product for 4 to 12 weeks, since that is the length the trials ran

Whichever active you choose, daytime sunscreen travels with it. Pigment darkens again in sunlight, and the 120-person arm of Hakozaki 2002 was itself run on top of a sunscreen. Guide 11 covers how to read SPF and PA labels.

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One line

Pick a name from the list of nine, give it 4 to 12 weeks, and wear sunscreen while you do.

The next guide takes on organic and natural cosmetic labelling — what those words are allowed to certify under the Korean standard.

📌 Related guides

📌 Niacinamide: How Much Is Enough (Guide 2)

📌 Arbutin vs Alpha-Arbutin: Korea’s 2–5% and the EU limits (Guide 15)

📌 Tranexamic Acid Cream: What the Melasma Trials Found (Guide 9)

📌 Adenosine 0.04%: Who Decided That Number (Guide 12)

📌 How to Read a Korean Cosmetic Ingredient List (Guide 14)

📌 Sunscreen SPF and PA: How to Read the Numbers (Guide 11)

About the author · Dr. J

📄 References

· Regulation on Review of Functional Cosmetics, Annex 4 — Types of functional cosmetics for which data submission is omitted (MFDS notification)

· Hakozaki T, Minwalla L, Zhuang J, et al. Br J Dermatol 2002;147(1):20-31

· Morag M, Nawrot J, Siatkowski I, et al. J Cosmet Dermatol 2015;14(3):185-190

· Kameyama K, Sakai C, Kondoh S, et al. J Am Acad Dermatol 1996;34(1):29-33

· Lee J, Jun H, Jung E, et al. Int J Cosmet Sci 2010;32(4):299-303

· SCCS Opinion on alpha-Arbutin and beta-Arbutin, SCCS/1642/22, adopted 31 January 2023

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This article summarises a public regulation and published research. It is information, not a diagnosis or a treatment plan. The figures are as written in the notification and in each abstract, and results differ from person to person. If a pigment change worries you, please speak with a professional.

— Dr. J Ingredient Notes

September 29, 2026