Collagen and peptides for skin: what helps hydration and elasticity?

A reader asks

Summary

• Oral collagen peptides have the best evidence. In the most recent meta-analysis (35 randomised trials, 2,534 people) skin hydration and elasticity improved on instrument measurements, and the change in elasticity needed at least 12 weeks [1]A. The effect is small, not a miracle.
• The evidence is disputed. When only trials without pharmaceutical-company funding, or only high-quality trials, were included, no benefit was seen [3]A, and a September 2026 re-analysis found reporting errors in earlier meta-analyses [4]A.
• Creams: there are a few small studies of peptide creams, mostly on wrinkles, not on hydration or elasticity. With palmitoyl pentapeptide (Matrixyl) wrinkles decreased in a study of 93 women [10]A, but the only peer-reviewed randomised trial of the copper peptide GHK-Cu that we know of found no measured difference [17]A.
• GHK-Cu with microneedling: in the lab, needles let the copper peptide through the skin [18]D, but there is no proper human trial of the combination [15]. In the only comparison the groups already differed at baseline, there was no difference from week 6, and pigment changes were more common [19]B.
• Nasal sprays and injections: we know of no published human study of skin hydration or elasticity. The strongest evidence for slowing skin ageing is for daily sunscreen [28]A and for vitamin A derivatives, the retinoids [29, 30]A.
• User experiences (not research): of 361 people, 254/361 (70%) reported some benefit and 74/361 (20%) some harm. Summary: What users report.

What is the most effective option without needles?

Short answer: oral collagen peptides, because they have by far the most randomised placebo-controlled human trials [1, 2, 3]A.

The benefit is still small and disputed [1, 2, 3]A: collagen may help a little, but do not expect miracles.

Products have not been compared, and the effect on hydration varied with the collagen source and the length of use [2]A, so one trial's result does not carry over to another product. In Finland collagen is a food supplement, which is a food [35]regulator. Basics: Collagen peptides.

Evidence at a glance

Each cell says what has been measured in people and at which level. The letter is the evidence level, not the result.

"-" = we know of no study that measured this.

By mouth: what has been studied on collagen peptides?

What the meta-analyses show

• Batool et al. 2026: 35 randomised trials, 2,534 people. Hydration (standardised mean difference 0.44), elasticity (0.62) and water loss through the skin (-0.39) improved. The effect depended on the length of use, not the amount: elasticity and the skin barrier needed at least 12 weeks. For wrinkles, roughness and skin density, the apparent benefit came from outlying trials, according to sensitivity analyses [1]A.
• Pu et al. 2023: 26 trials, 1,721 people. Hydration and elasticity improved compared with placebo, but the trials had several sources of bias [2]A.
• Nukaly et al. 2026: 19 trials of oral and topical peptides: hydration and brightness improved, wrinkles a little, elasticity inconsistently [6]A.
• Myung and Park 2025: 23 trials, 1,474 people. All together: hydration, elasticity and wrinkles improved. In trials without pharmaceutical-company funding, and in high-quality trials, there was no effect on any measure. Conclusion: there is no clinical evidence [3]A.

What trials used: raw material, amount and duration

These are amounts used in trials, not recommendations. The products studied were collagen broken down into peptides, that is hydrolysed collagen.

• 69 women (aged 35 to 55) took 2.5 g or 5 g of collagen hydrolysate or placebo a day for 8 weeks. Elasticity improved with both amounts, but the change in hydration was not statistically significant. No side effects were seen [7]A.
• 114 women (aged 45 to 65) took 2.5 g of a raw material called Verisol or placebo a day for 8 weeks. The volume of eye wrinkles fell by 20%, and skin samples contained 65% more type I procollagen than in the placebo group [8]A.
• In two placebo-controlled trials skin hydration improved within 8 weeks, and collagen density measured by ultrasound rose already within 4 weeks. One of the authors worked at Rousselot, a company that makes collagen [9]A.

Trials lasted between 2 and 12 weeks [2]A, and the change in elasticity only showed in the meta-analysis with at least 12 weeks of use [1]A. More on amounts used in trials: Collagen peptides: amounts used in studies.

How could eaten collagen work in the skin?

Collagen is broken down in the gut into amino acids and small fragments. One fragment, prolyl-hydroxyproline, has been measured in human blood after eating collagen, and it sped up the growth of mouse skin cells in culture [24]D. This has not been shown in human skin: it is an explanation model, not proof.

Creams and serums: which types of peptides are there, and do they work?

A review divides topical peptides into four groups: signal peptides, enzyme-inhibitor peptides, neurotransmitter-inhibitor peptides and carrier peptides [14]. A systematic review found 15 studies of cosmetic peptides that stimulate collagen production; only six had a placebo control and five were double-blind [13]. More: Peptides in skincare.

Copper peptide GHK-Cu

The positive side: the copper peptide has more than 40 years of lab and animal research [15]. According to the often-cited 2002 studies, 12 weeks of a face cream improved skin density and reduced fine lines in 71 women, and an eye cream did better than placebo in 41 women [15]E, not peer-reviewed. According to a 2026 systematic review (20 studies, 2 of them randomised human trials), GHK-Cu improved patient satisfaction after laser resurfacing and reduced wrinkle volume and depth compared with controls [16]A.

Caveats: the 2002 studies were published only as conference abstracts, not as peer-reviewed articles [15]E, not peer-reviewed. In the only peer-reviewed randomised trial we know of (13 patients after laser treatment), redness, wrinkles and skin quality did not differ on measurement, although the GHK-Cu group rated their own skin better [17]A. According to a review, a small study in a little-known journal found less wrinkle volume and depth after 8 weeks compared with a control [15]B. Hydration and elasticity have not been measured in a peer-reviewed study. More: GHK-Cu (copper peptide).

Matrixyl (palmitoyl pentapeptide-4)

In a double-blind trial, 93 women (aged 35 to 55) applied a cream with the peptide to one side of the face and the same cream without it to the other for 12 weeks. On the peptide side wrinkles and fine lines decreased, and the cream was well tolerated. The researchers were from the cosmetics company Procter & Gamble, and the trial did not measure hydration or elasticity [10]A. In a small Indonesian trial (21 women, 8 weeks) palmitoyl pentapeptide-4 did better than acetyl hexapeptide and placebo; the result is preliminary [11]A.

Argireline (acetyl hexapeptide)

In a Chinese placebo-controlled trial, 60 people (3:1 active and placebo) applied the product to eye wrinkles for 4 weeks. In the subjective assessment total anti-wrinkle efficacy was 48.9% in the active group and 0% in the placebo group, and skin roughness decreased on measurement only in the active group [12]A. In a German split-face comparison of 19 women (4 weeks), the peptide side did not differ statistically from the other side [41]B. The studies measured wrinkles, not hydration or elasticity.

GHK-Cu and microneedling: does the combination work?

The idea: the copper peptide passes intact skin poorly. In the lab, peptide and copper passed through human skin punctured with microneedles, and almost nothing through intact skin [18]D.

What is known in people: according to a 2026 systematic review, GHK-Cu delivered by microneedles has not been evaluated in a single registered, adequately powered randomised human trial [15]. We know of no registered trial of GHK-Cu on its own for skin ageing or with microneedling [40]E, not peer-reviewed.

The only comparisons are scar studies: in an Indian study, acne scars were treated for 16 weeks with either a dermaroller alone (1.5 mm needles) or a dermaroller plus copper-peptide serum. The groups already differed at baseline, the copper-peptide group's scar scores were slightly worse throughout, there was no difference from week 6 on, and pigment changes were more common in the copper-peptide group [19]B. In another case series, scars decreased more in the combination group than with the dermaroller alone [15]B. Scars are not the same thing as hydration and elasticity.

Risks at home: a product applied before microneedling can end up in the deeper layers of the skin. Three women developed a hard-to-treat foreign-body reaction (granuloma) on the face, two after the same vitamin C serum [27]B. A systematic review found 15 such cases; most involved a motorised microneedling pen and vitamin C [26]B.

Nasal sprays and injectable peptides

Nasal sprays: we know of no published study of peptide or collagen nasal sprays for skin ageing. The tanning agent melanotan II, sold online as a nasal spray, is on Fimea's medicines list, so it is a medicinal substance in Finland [39]regulator, and it has no EU marketing authorisation [46]regulator. In a British case report a young woman developed melanoma of the oral mucosa after using a melanotan II spray; a causal link has not been shown [33]B. More: Melanotan II.

Injections: you often hear that only injections work. On this topic, however, human studies exist only for oral collagen and creams [1, 10]A: we know of no published human study of injected peptides for skin hydration or elasticity. According to the FDA, compounded injectable GHK-Cu may cause immune reactions, and there are few human safety data [38]regulator. Fimea urges people not to use injectable peptides bought online, such as BPC-157 [34]regulator. GHK-Cu is also sold in injectable blends such as Glow; see Peptide blends and all blends. Authorities’ peptide decisions: News.

Promising, but so far only in animal and cell studies

These findings explain the interest, but they have not been tested in people with the same measure.

• Copper peptide increases collagen and connective tissue no human studies

  In cell culture GHK-Cu increased collagen production by connective-tissue cells (fibroblasts) at very low concentrations [20]D. In rats, GHK-Cu injected into wound chambers placed under the skin increased collagen and other connective tissue depending on concentration, while a control peptide had no effect [21]C.

  If it held in humans: skin could produce more collagen, which might show as firmness.

  Why it might not translate: a cell culture and a wound chamber are not intact facial skin, which a cream barely passes [18]D. The authors of the cell study included the researcher who first isolated the substance [15, 20]. In people, improved skin density and thickness have been reported only in conference abstracts [15]E, not peer-reviewed.

  Evidence now: on this page two primary experiments from the same French group [20, 21]; there are also animal studies on wound healing from other research groups. We know of no registered skin-ageing trial [40]E, not peer-reviewed.

• Microneedles carry copper peptide through the skin no human studies

  In pieces of human and pig skin, peptide and copper passed through skin punctured with microneedles, while almost nothing passed intact skin; no obvious irritation was seen on pig skin [18]D.

  If it held in humans: the active ingredient of a serum would reach where collagen is made.

  Why it might not translate: uptake has not been measured in living human skin. Uptake does not tell whether the skin improves, and a substance carried deeper can also cause reactions [26, 27]B.

  Evidence now: one lab study. According to a review, it has not been tested in a single published human trial in ten years [15].

• Part of the Matrixyl peptide increases collagen production no human studies

  A five-amino-acid sequence (KTTKS) from the precursor of type I collagen was the smallest part that increased collagen and fibronectin production in connective-tissue cells in culture [22]D.

  If it held in humans: a cream could increase the skin's own collagen, not just smooth the surface.

  Why it might not translate: in creams the sequence is attached to a fatty acid (palmitoyl-KTTKS), and in people the trial measured wrinkles from images, not collagen in the skin [10]A. In the cell study the sequence was not in a cream.

  Evidence now: one cell study on collagen; in people one wrinkle trial by a cosmetics company [10]A and one small trial [11]A.

What to expect: a randomised trial of GHK-Cu for healing acute skin wounds is recruiting, with results expected around February 2027 [40]E, not peer-reviewed. We know of no registered trial on skin ageing or microneedling.

Medications, clinic treatments and sunscreen: stronger evidence

These are not peptides, but they have stronger evidence than any peptide.

• Sunscreen every day. In an Australian randomised trial of 903 people under 55, skin ageing over 4.5 years was 24% less in those who used sunscreen daily than in those who used it at their discretion [28]A.
• Retinol (vitamin A) as a cream. In a randomised arm study of 36 elderly people (mean age 87), retinol lotion reduced fine wrinkles over 24 weeks more than the base lotion alone [29]A.
• Tretinoin (a medicine). In a 16-week double-blind trial, sun-damaged facial skin improved in 14 of 15 patients with tretinoin and in none with the base cream. The side effect was skin irritation [30]A.
• Microneedling in a clinic. In a review of 21 studies (723 patients), 83% were satisfied, but outcome measures varied [25]B.
• Biostimulator (poly-L-lactic acid, injected in a clinic). In a review of 11 randomised trials skin thickness improved, but the evidence was of low quality, and harms included bruising and nodules [31]A.

What do users themselves report?

The data are 785 Reddit posts and comments, each one read. Counting only products used without needles, of 361 people 254/361 (70%) reported some benefit and 74/361 (20%) some harm. The most common benefits among oral collagen users were hair or lashes, joints or recovery and nails; 20/229 (9%) mentioned more hydrated skin. Of copper-peptide cream users, 13/35 (37%) reported a harm.

One person can be in several rows. "Noticed no effect" is a share of those who stated an outcome. "-" = fewer than 5 people, no shares.

Full summary, tables and quotes: What users report

Harms and safety

• Oral collagen: no side effects were seen in an 8-week trial [7]A, and according to a meta-analysis peptides were well tolerated [6]A. The collagen source varies [2]A, so check the origin (for example fish) on the pack.
• Peptide creams: well tolerated [10]A, with no irritation reported [41]B.
• Injectable peptides: according to Fimea, injectable products bought online may contain impurities that can cause serious harm [34]regulator.

In general: Side effects and safety.

What speaks against it and what is not known

Contrary evidence

• Independent and high-quality collagen trials showed no effect [3]A.
• According to a re-analysis, two meta-analyses had misreported data from the original trials and combined measures that do not fit together. When the amounts used were taken into account, no benefit was found [4]A.
• The only peer-reviewed randomised trial of the copper peptide that we know of found no measured difference [17]A.
• In mice, eaten collagen reduced wrinkles caused by UVB radiation [23]C. In people, a combination of astaxanthin and collagen improved elasticity over 12 weeks but did not reduce DNA damage from artificial UV radiation [42]A, so there is no human evidence of UV protection.

Results of independent trials vary. In an independent 6-month trial in 56 older women, collagen did not improve forearm skin elasticity [43]A; in another independent trial in menopausal women it improved elasticity by 12% from baseline [44]A.

What is not known

• Whether one collagen product is better than another: products have not been compared with each other.

Law and rules in Finland and the EU

• Collagen peptides are food supplements regulated by food law [35]regulator. In the EU Register of health claims, the skin and joint claims for collagen are marked as non-authorised, and the authorised claim on collagen concerns vitamin C [36]regulator.
• Peptide creams and serums are cosmetics. Under the EU Cosmetics Regulation a cosmetic product is intended for the external parts of the body, and an injected substance is not a cosmetic [37]regulator.
• Injectable peptides can be medicines in Finland, and Fimea warns against injectable peptides bought online [34]regulator. Melanotan II is on Fimea's medicines list and has no EU marketing authorisation [39, 46]regulator. More: Peptides and the law and how to read a certificate of analysis (COA). This is not legal advice (disclaimer).

Quality, the grey market and marketing claims

1. Collagen: trials used hydrolysed collagen, also called collagen peptides; the ingredient list shows whether a product is that. Amounts used in trials: study amounts (not a recommendation).
2. Creams: on the ingredient list the copper peptide is called copper tripeptide-1 [45], and trials also used the names palmitoyl pentapeptide-4 and acetylhexapeptide-3 [11]A. Concentration varies by product, and a trial of one cream says nothing about another [10]A. Concentrations used in studies: GHK-Cu and skincare peptides.
3. A marketing line says nothing about effect. There is no authorised skin or health claim for collagen [36]regulator.
4. Injectable peptides sold "for research use" are a grey market: according to Fimea the label means the product is not intended for humans [34]regulator.

We do not recommend skincare products or shops, and this page has no partner links. Some price comparisons on the site contain clearly marked partner links (About us).

Who researches this and who wrote this page

A benefit was seen only in collagen trials funded by pharmaceutical companies [3]A, the largest peptide-cream trial was run by a cosmetics company [10]A, and about a third of the GHK-Cu literature comes from one small circle of researchers [15].

Who wrote this page: the editors

This page was written by the Molecular Recovery editors from a reader's question. The draft was made with AI assistance, and the sources and claims were checked separately (AI policy). The page has not been medically reviewed. Basics: What are peptides? All substances: Peptides A-Z.

FAQ

Read the research yourself: sources

Each source opens the original publication or the authority’s page. The level says what the source itself reports.

1. Batool A, Abbas MS, Farooq R, et al. Oral Collagen Peptides and Skin Rejuvenation: A Systematic Review and an Updated Meta-Analysis of Randomized Controlled Trials. J Cosmet Dermatol. 2026;25(7):e71041. doi.org A
2. Pu SY, Huang YL, Pu CM, et al. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients. 2023;15(9):2080. PMID 37432180 A
3. Myung SK, Park Y. Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Med. 2025;138(9):1264-1277. PMID 40324552 A
4. Grimes DR, Mahto A. Hydrolyzed Collagen for Skin Aging Meta-Analyses Are Unreliable. J Cosmet Dermatol. 2026;25(10):e71208. doi.org A
5. de Miranda RB, Weimer P, Rossi RC. Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis. Int J Dermatol. 2021;60(12):1449-1461. PMID 33742704 A
6. Nukaly HY, Halawani IR, Irtaza HM, et al. Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials. Front Med (Lausanne). 2026;13:1618306. PMID 41924746 A
7. Proksch E, Segger D, Degwert J, et al. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study. Skin Pharmacol Physiol. 2014;27(1):47-55. PMID 23949208 A
8. Proksch E, Schunck M, Zague V, et al. Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis. Skin Pharmacol Physiol. 2014;27(3):113-119. PMID 24401291 A
9. Asserin J, Lati E, Shioya T, Prawitt J. The effect of oral collagen peptide supplementation on skin moisture and the dermal collagen network: evidence from an ex vivo model and randomized, placebo-controlled clinical trials. J Cosmet Dermatol. 2015;14(4):291-301. PMID 26362110 A
10. Robinson LR, Fitzgerald NC, Doughty DG, et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-160. PMID 18492182 A
11. Aruan RR, Hutabarat H, Widodo AA, et al. Double-blind, Randomized Trial on the Effectiveness of Acetylhexapeptide-3 Cream and Palmitoyl Pentapeptide-4 Cream for Crow's Feet. J Clin Aesthet Dermatol. 2023;16(2):37-43. PMID 36909866 A
12. Wang Y, Wang M, Xiao S, et al. The anti-wrinkle efficacy of argireline, a synthetic hexapeptide, in Chinese subjects: a randomized, placebo-controlled study. Am J Clin Dermatol. 2013;14(2):147-153. PMID 23417317 A
13. Michalek IM, Lelen-Kaminska K, Caetano Dos Santos FL. Peptides stimulating synthesis of extracellular matrix used in anti-ageing cosmetics: Are they clinically tested? A systematic review of the literature. Australas J Dermatol. 2019;60(4):e267-e271. PMID 30941744 (review)
14. Gorouhi F, Maibach HI. Role of topical peptides in preventing or treating aged skin. Int J Cosmet Sci. 2009;31(5):327-345. PMID 19570099 (review)
15. Najafi N, Maatouk H, Vardanyan KG, et al. A Systematic Review of the Mechanisms and Therapeutic Applications of GHK-Cu in Topical Microneedle Delivery: A Case for Expanded Clinical Trials. Arch Intern Med Res. 2026;9(3):269-293 (full text PMC13604022). PMID 42787770 (review)
16. Mokhtar J, Mohamad B, Haddad J, et al. The Regenerative Potential of GHK-Cu in Aesthetic Medicine. Aesthet Surg J. 2026 (online 20 Aug 2026). PMID 42619529 (review)
17. Miller TR, Wagner JD, Baack BR, Eisbach KJ. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg. 2006;8(4):252-259. PMID 16847171 A
18. Li H, Low YS, Chong HP, et al. Microneedle-Mediated Delivery of Copper Peptide Through Skin. Pharm Res. 2015;32(8):2678-2689. PMID 25690343 D
19. Vignesh NR, Balakumaran C, Kumar NA, et al. A study comparing the effect of dermaroller versus dermaroller with copper peptide in the management of acne scars. J Cutan Aesthet Surg. 2025;19:149-157. doi.org B
20. Maquart FX, Pickart L, Laurent M, et al. Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. FEBS Lett. 1988;238(2):343-346. PMID 3169264 D
21. Maquart FX, Bellon G, Chaqour B, et al. In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds. J Clin Invest. 1993;92(5):2368-2376. PMID 8227353 C
22. Katayama K, Armendariz-Borunda J, Raghow R, et al. A pentapeptide from type I procollagen promotes extracellular matrix production. J Biol Chem. 1993;268(14):9941-9944. PMID 8486721 D
23. Cho CH, Lim W, Sim WJ, Lim TG. Oral administration of collagen peptide in SKH-1 mice suppress UVB-induced wrinkle and dehydration through MAPK and MAPKK signaling pathways, in vitro and in vivo evidence. Food Sci Biotechnol. 2024;33(4):955-967. PMID 38371682 C
24. Shigemura Y, Iwai K, Morimatsu F, et al. Effect of Prolyl-hydroxyproline (Pro-Hyp), a food-derived collagen peptide in human blood, on growth of fibroblasts from mouse skin. J Agric Food Chem. 2009;57(2):444-449. PMID 19128041 D
25. Foppiani JA, Fanning JE, Beltran K, et al. Microneedling for Facial Rejuvenation: A Systematic Review. Aesthetic Plast Surg. 2025;49(17):4949-4960. PMID 40542236 (review)
26. Friedmann DP, Mehta E, Verma KK, Harris R. Granulomatous Reactions From Microneedling: A Systematic Review of the Literature. Dermatol Surg. 2025;51(3):263-266. PMID 39584690 (review)
27. Soltani-Arabshahi R, Wong JW, Duffy KL, Powell DL. Facial allergic granulomatous reaction and systemic hypersensitivity associated with microneedle therapy for skin rejuvenation. JAMA Dermatol. 2014;150(1):68-72. PMID 24258303 B
28. Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med. 2013;158(11):781-790. PMID 23732711 A
29. Kafi R, Kwak HS, Schumacher WE, et al. Improvement of naturally aged skin with vitamin A (retinol). Arch Dermatol. 2007;143(5):606-612. PMID 17515510 A
30. Weiss JS, Ellis CN, Headington JT, et al. Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled study. JAMA. 1988;259(4):527-532. PMID 3336176 A
31. Signori R, Barbosa AP, Cezar-Dos-Santos F, et al. Efficacy and Safety of Poly-l-Lactic Acid in Facial Aesthetics: A Systematic Review. Polymers (Basel). 2024;16(18):2564. PMID 39339028 A
32. Avcil M, Akman G, Klokkers J, et al. Efficacy of bioactive peptides loaded on hyaluronic acid microneedle patches: A monocentric clinical study. J Cosmet Dermatol. 2020;19(2):328-337. PMID 31134751 B
33. Yassin Alsabbagh A, Bhujel N, Singh RP. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? Int J Oral Maxillofac Surg. 2025;54(9):806-808. PMID 40210573 B
34. Fimea. Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. fimea.fi regulator
35. Finnish Food Authority (Ruokavirasto). Food supplements: requirements for the food sector. ruokavirasto.fi regulator
36. European Commission. EU Register of nutrition and health claims made on foods (read 12 Oct 2026; collagen claims POL-HC-6212, POL-HC-6962, POL-HC-6963, POL-HC-8291 and POL-HC-8433 non-authorised; POL-HC-6505 on vitamin C authorised). European Commission regulator
37. Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products, Articles 2, 3 and 10 (Official Journal copy hosted by the European Commission). European Commission regulator
38. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 22 Apr 2026; GHK-Cu for injectable routes, nominated and withdrawn). fda.gov regulator
39. Fimea. Regulation on the list of medicinal substances 230/2025, annex 1 A (melanotan I and melanotan II classified as medicines; read 13 Oct 2026). Finlex regulator
40. ClinicalTrials.gov. NCT07437586: Topical GHK-Cu Gel for Acute Skin Wound Healing (Hudson Biotech; phase 2; randomised, vehicle-controlled; recruiting; checked 13 Oct 2026). The registry had no trial of GHK-Cu on its own for skin ageing or with microneedling on 13 Oct 2026 (NCT05932732 tested a device facial with a GHK-Cu serum). ClinicalTrials.gov E, not peer-reviewed
41. Henseler H. Investigating the effects of Argireline in a skin serum containing hyaluronic acids on skin surface wrinkles using the Visia Complexion Analysis camera system for objective skin analysis. GMS Interdiscip Plast Reconstr Surg DGPW. 2023;12:Doc09. PMID 38024099 B
42. Yoon HS, Cho HH, Cho S, et al. Supplementating with dietary astaxanthin combined with collagen hydrolysate improves facial elasticity and decreases matrix metalloproteinase-1 and -12 expression: a comparative study with placebo. J Med Food. 2014;17(7):810-816. PMID 24955642 A
43. Guadanhim LRS, Miot HA, Soares JLM, et al. Efficacy and Safety of Topical or Oral Hydrolyzed Collagen in Women with Dermatoporosis: A Randomized, Double-Blind, Factorial Design Study. Dermatol Ther (Heidelb). 2023;13(2):523-534. PMID 36547800 A
44. Duangjai A, Srivilai J, Nangola S, Amornlerdpison D. Calcium and Vitamin D Supplementation with and Without Collagen on Bone Density and Skin Elasticity in Menopausal Women: A Randomized Controlled Study. Clin Pract. 2025;15(9):168. PMID 41002783 A
45. Wang J, Tao K, Huang H, Chang H. Augmented Skin Beneficial Effects of Thermus Thermophilus and Bacillus Subtilis Mixed-Culture Ferment Extract by Tripeptide GHK-Cu. Skin Res Technol. 2026;32(8):e70360 (cited for the ingredient name). PMID 42573538 (review)
46. European Medicines Agency. Medicines data: centrally assessed human medicines (status 13 Oct 2026: no melanotan II product; afamelanotide authorised as Scenesse). EMA regulator

Research details checked on 13 Oct 2026. Authority pages and registers read on 12-13 Oct 2026.

Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. For a review, the level says what kind of study the claim rests on. Without a level: the reviews’ interpretations and statements that no studies were found.

Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.