Tag: collagen peptides

🇰🇷 한국어판

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

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

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

📌 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