🇰🇷 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
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
📌 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
