SkincareCosmetic PeptidesAug 2026

Peptide Serums: Which Cosmetic Peptides Have Evidence Behind Them

A peptide serum is only as good as the specific peptide in it, and the published evidence is much stronger for some of those names than for others. This guide goes through the peptides you find on a serum label one at a time, gives you the trial behind each one with its size and its population, and is clear about the ones where the trial does not exist.

Studies in the 2019 review

6 of 15

That used a placebo control

3 ppm

Peptide level in the 93-woman trial

What A Peptide Serum Is

A peptide is a short chain of amino acids, the same building blocks that make up the proteins in your skin. A cosmetic peptide is a short chain that has been designed or selected because it resembles a fragment of one of those proteins, and the idea behind a peptide serum is that the fragment acts as a message telling skin cells to build more of the parent protein.

That idea has some support in the lab. A 2026 safety paper in Current Research in Toxicology, written by researchers at The Procter and Gamble Company and a consultancy, ran seven peptides through six bioinformatic tools and reported that palmitoyl hexapeptide-12, caffeoyl hexapeptide-9 and palmitoyl pentapeptide-4 all show sequence homology with skin extracellular matrix proteins including collagen, elastin and fibronectin, without the safety concerns the same tools raised for the amanitin and conotoxin peptides in the set. Sequence homology with collagen is a reason to test an ingredient. It is not a clinical result.

Worth separating early: the peptides in a skincare serum are a different subject from the injectable and research peptides most people mean when they say the word. Different molecules, different routes, different rules. If that is what you came for, the what are peptides page covers it and this page stays on cosmetics.

The Names On The Label

Serum labels use ingredient names, not brand names, so the trade name on the front of the box and the name in the ingredient list are often different words for the same molecule. The molecular weights and the alternate names below are read from the PubChem compound records, and those weights matter for the section after this one.

Ingredient name	Also sold as	Molecular weight
Copper tripeptide-1	GHK-Cu, copper peptide, prezatide copper	402.92 g/mol
Tripeptide-10 citrulline	Decorinyl	530.6 g/mol
Palmitoyl tripeptide-1	Pal-GHK, palmitoyl-GHK tripeptide	578.8 g/mol
Palmitoyl tripeptide-5	Syn-Coll	611.9 g/mol
Palmitoyl tetrapeptide-7	Palmitoyl-GQPR, N-palmitoylrigin	694.9 g/mol
Palmitoyl pentapeptide-4	pal-KTTKS, Matrixyl	802.1 g/mol
Acetyl hexapeptide-8	Acetyl hexapeptide-3, Argireline	887.0 g/mol
Acetyl octapeptide-3	SNAP-8	1075.2 g/mol

One naming point trips people up more than the rest. Published studies use acetyl hexapeptide-3 and acetyl hexapeptide-8 as if they were two ingredients, and the marketing name Argireline appears alongside both. PubChem resolves all three of those names to a single compound record, CID 71587772, with the formula C35H62N14O11S. So when you compare a study on acetyl hexapeptide-3 with a serum listing acetyl hexapeptide-8, you are looking at the same molecule under two labels.

A second one is worth knowing if you are comparing copper peptide products. The PubChem record for palmitoyl tripeptide-1 gives its systematic name as N-palmitoyl-glycyl-histidyl-lysine, which is the same GHK tripeptide as the copper version carrying a palmitic acid tail instead of a copper ion. The 2025 BioImpacts review discusses the two side by side as GHK-Cu and Pal-GHK, the metal complex and the palmitoylated derivative of the same peptide. Same starting sequence, different modification, different weight, and different evidence.

Whether It Gets Past The Surface

Every claim a peptide serum makes depends on the peptide reaching the layer where the claim happens, and that is the part of the story labels never address. The starting point is a 2000 paper in Experimental Dermatology by Bos and Meinardi, who argued that a compound needs a molecular weight under 500 Dalton to be absorbed through skin. They built the argument from three observations: nearly all common contact allergens are under 500 Dalton, the commonly used topical dermatology drugs are all under 500 Dalton, and the drugs used in transdermal delivery systems are all under 500 Dalton.

It is a rule of thumb the authors proposed, not a measured ceiling, and it has documented exceptions. A 2005 paper in Bioorganic and Medicinal Chemistry by researchers at Novartis tested cyclosporin prodrugs on rat and human skin in vitro, and reported that adding a polar side chain achieved high skin permeation with compounds in the 1200 to 1600 Dalton range, which the authors described as being in contrast with the 500 Dalton rule. Those were purpose-built prodrugs rather than cosmetic peptides, so read it as a caution against treating 500 Dalton as a wall, not as evidence that any large peptide gets through.

Look back at the table and only copper tripeptide-1, at 402.92 g/mol, sits under that figure. Everything else is above it, and acetyl octapeptide-3 is roughly twice it.

What a US FDA laboratory measured

Kraeling and colleagues at the FDA Center for Food Safety and Applied Nutrition ran acetyl hexapeptide-8 through in vitro diffusion cells using hairless guinea pig skin and human cadaver skin. They applied an oil-in-water emulsion containing 10 percent of the peptide at a dose of 2 mg per square centimetre, left it for 24 hours, then washed the surface and analysed the layers separately. This is excised skin in a laboratory apparatus, not living skin on a face.

Most of the applied peptide washed off the surface of both skin types.
What penetrated stayed mostly in the stratum corneum: 0.54 percent of the applied dose in guinea pig skin and 0.22 percent in human skin.
Total peptide found in the epidermis was similar in both at 0.01 percent of the applied dose.
No peptide was detected in the dermis, or in the buffer collected underneath the skin, in either species.
No hexapeptide metabolite was detected in any layer.

Read that carefully, because it is easy to over-read in both directions. The study was designed to evaluate safety, and its authors framed the question as whether cosmetic peptides reach deep layers and stimulate biological activity there. For one peptide, from one formulation, in one assay, the answer was that almost none of it did. That is a real problem for the specific marketing story that acetyl hexapeptide-8 interferes with nerve signalling the way an injected muscle relaxant does, because the machinery that story describes sits well below the layers where the peptide was found. It is not proof that a serum containing it does nothing measurable at the surface, which is a separate question answered by the trials further down.

Copper peptides look better on this measure but the picture is mixed. A 2025 review in BioImpacts by Mortazavi and colleagues concluded that GHK-Cu and Pal-GHK are effective and relatively skin permeable, and that their permeability could be increased further with enhancement methods, while the same review reported what it called a surprising absence of clinical studies using them and rested its case for the ingredient on cell studies. Both halves of that belong together.

What The Trials Found

Here is each peptide with the human study behind it, the number of people in each arm, and who those people were. The arm sizes matter more than usual here, because several of these trials split a small group of volunteers three or four ways.

Palmitoyl pentapeptide-4 (pal-KTTKS, Matrixyl)

Robinson and colleagues ran 93 Caucasian women aged 35 to 55 through a 12-week double-blind, placebo-controlled, split-face, left-right randomised study. One side got a moisturiser, the other side got the same moisturiser containing 3 parts per million of pal-KTTKS, which is 0.0003 percent. The peptide side gave a significant improvement over the control side for wrinkles and fine lines on both quantitative image analysis and expert grader assessment, and it was well tolerated. In self-assessment the subjects reported significant fine line and wrinkle improvement, and the authors described the effects on other facial parameters as directional rather than significant.

Split-face means each woman was her own control, which is a strong design at this size. All six authors were listed at The Procter and Gamble Company. The population was Caucasian women in a narrow age band, so it says nothing about other skin types or about men.

Palmitoyl pentapeptide-4 against acetyl hexapeptide-3, in Asian skin

A 2023 double-blind randomised trial from Kristen Krida Wacana University in Jakarta put the two head to head on crow's feet. Twenty-one Indonesian women aged 26 to 55 were divided into three groups, an acetyl hexapeptide-3 cream, a palmitoyl pentapeptide-4 cream and a placebo, so roughly seven women per group. Cream was applied twice daily to the periorbital area for eight weeks and assessed with a corneometer, a tewameter, a cutometer, digital photography and a crow's feet grading scale. Improvements were found in several subjects on both peptides, and palmitoyl pentapeptide-4 appeared to do better than acetyl hexapeptide-3 on the data, the clinical photos and the self-assessment questionnaire.

Seven people per arm is a pilot, and the authors said so themselves, calling it an initial study and asking for further work with a more adequate number of samples and a longer duration. Its value is that it was run in Southeast Asian skin, which most of this literature is not.

Acetyl hexapeptide-8 (Argireline)

Wang and colleagues at the Second Hospital of Xi'an Jiaotong University randomised 60 Chinese subjects to argireline or placebo in a ratio of 3 to 1, which works out at roughly 45 people on the peptide and 15 on placebo. It was applied to peri-orbital wrinkles twice daily for four weeks. On the subjective global assessment the argireline group was scored at 48.9 percent total anti-wrinkle efficacy against 0 percent for placebo. On the objective measure, silicone replicas of the treated skin analysed by a wrinkle-analysis apparatus, the roughness parameters all decreased in the argireline group at p below 0.01 while no decrease was obvious in the placebo group at p above 0.05.

Four weeks is short, the placebo arm was about 15 people, and the abstract does not state what concentration of peptide was used, which makes it hard to match against a product on a shelf. The 48.9 percent figure is a rating on a global assessment scale, not a percentage reduction in wrinkle depth.

Tripeptide-10 citrulline, with acetyl hexapeptide-3

Raikou and colleagues in Athens randomised 24 healthy volunteers across four groups for 60 days: the combination, tripeptide-10 citrulline alone, acetyl hexapeptide-3 alone, and neither. That is about six people per group. They measured skin microtopography and transepidermal water loss. The authors reported that the results confirm the anti-wrinkle activity of acetyl hexapeptide-3 and show a significant decrease in water loss with it, and that they provided clinical evidence for the anti-wrinkle efficacy of tripeptide-10 citrulline, while stating that the mechanism by which the two peptides might act synergistically was not clear in the study.

Six people per arm across four arms is a very small design. Take the direction, not the conclusion.

Copper tripeptide-1 (GHK-Cu)

Miller and colleagues randomised patients to a post-treatment skin regimen with or without GHK-Cu after CO2 laser resurfacing of the skin around the mouth, and 13 patients completed the study across the two arms. Computer analysis and blinded evaluators found no statistically significant difference between groups for earlier resolution of redness. All the patients had significant improvement in wrinkles and overall skin quality, and no differences were found between the groups on that either. The patient questionnaire told a different story: it showed a significant difference favouring the GHK-Cu group for improvement in overall skin quality, at P equals 0.04.

All three of those findings belong in the same sentence, and quoting only the questionnaire result would misrepresent the study. It is also a wound-healing setting after a laser procedure, not everyday serum use, and 13 completers split two ways is a very small trial. For the mechanism and the topical formats, see the GHK-Cu topical page.

Acetyl octapeptide-3 (SNAP-8)

Searching PubMed for acetyl octapeptide-3 on 5 August 2026 returned two records, and both are clinical studies that deliver the peptide through a microneedle patch rather than through a serum. One is a 2024 Annals of Dermatology study in 24 healthy subjects of a dissolving hyaluronic acid patch carrying acetyl octapeptide-3, L-ascorbic acid 2-glucoside and sodium cyclic lysophosphatidic acid, with the active patch on one eye and a placebo patch on the other for 28 days, which reported better wrinkle improvement, lower water loss and better elasticity than the placebo side. In the other, Avcil and colleagues ran a 12-week monocentric study of hyaluronic acid microneedle patches loaded with arginine and lysine polypeptide, acetyl octapeptide-3, palmitoyl tripeptide-5, adenosine and seaweed extracts, applied to the outer corner of each eye and to the forearm in healthy subjects with aged skin. They reported a 25.8 percent decrease in fine lines and wrinkles, 15.4 percent better hydration, and dermal density and thickness up 14.2 percent and 12.9 percent.

Five active components in the Avcil patch means no single ingredient can be credited there, and those authors said only that the ingredients might possibly act synergistically. The 2024 patch carries three actives, so the same limit applies to it. Microneedles physically puncture the stratum corneum, which is exactly the barrier a serum has to cross, so neither result transfers to a serum. All five Avcil authors are listed at commercial companies rather than at a university or hospital, and four of the five authors on the 2024 patch study are listed at the patch manufacturer. The SNAP-8 page covers the ingredient itself.

Palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7

Searching PubMed for palmitoyl tetrapeptide-7 as a plain term on 5 August 2026 returned four records, and none of them tests that peptide by itself against a placebo. The closest is a 2024 study in Skin Research and Technology of an eye cream built on a four-part active complex: yeast and rice fermentation filtrate, N-acetylneuraminic acid, palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7. Over 12 weeks the authors reported hydration up 28.12 percent, elasticity up 18.81 percent and collagen production up 54.99 percent, with dermatologist and participant ratings improving by week 8. The fibroblast proliferation and collagen findings in the same paper come from a human skin fibroblast model, which is cell work.

Two of the four actives are peptides, so nothing here is attributable to either peptide alone. PubMed indexes the record as a randomised controlled trial, but the abstract does not describe a control or placebo arm and reports the changes against baseline. Four of the authors, including the first, are listed at the research and development centre of a cosmetics company, and the paper states that no conflict of interest was reported.

The Comparison Against Tretinoin

The question everyone asks is whether a peptide product can stand next to a retinoid, and there is a real trial that gets close. Fu and colleagues published an 8-week randomised parallel-group study in the British Journal of Dermatology in 2010, with 196 women who had moderate to moderately severe wrinkles around the eyes, after a two-week washout.

Arm	What they used	Size
Cosmetic regimen	SPF 30 lotion with 5% niacinamide, peptides and antioxidants, a cream with niacinamide and peptides, and a targeted product with niacinamide, peptides and 0.3% retinyl propionate	n = 99
Prescription regimen	0.02% tretinoin plus an SPF 30 moisturising sunscreen	n = 97

The cosmetic regimen significantly improved wrinkle appearance at 8 weeks relative to tretinoin, and no significant difference was detected at 24 weeks, in a self-selected continuation cohort of 25 per arm, at P equals 0.74 and P equals 0.77 on the two measures. It was also significantly better tolerated than tretinoin through 8 weeks on every measure they used, including redness grading, dryness grading, water loss through the skin barrier and stratum corneum protein changes.

What that result is not: evidence about peptide serums. The cosmetic arm was a three-product regimen containing 5 percent niacinamide, unspecified peptides, antioxidants and 0.3 percent retinyl propionate, and retinyl propionate is a vitamin A ester, so there was a retinoid in the cosmetic arm too. The trial compared two regimens, and it cannot separate out what the peptides did. The comparator was 0.02 percent tretinoin, a low strength. The 24-week comparison rests on self-selected continuation cohorts of 25 subjects per arm rather than on the full 196, and the authors report that the mean cohort responses were not consistent with those of the full study population. The lead author was at The Procter and Gamble Company.

So the honest read is that a well-built cosmetic regimen held its own against a low-strength prescription retinoid in one 196-woman trial, and that this tells you about the regimen rather than about peptides. For context on the size of the peptide side, the 2019 systematic review below counted 15 clinical studies across the entire extracellular matrix peptide category. The retinol guide and the vitamin C serum guide cover what those two actives have behind them. Where a peptide belongs in a routine alongside them is a question for a dermatologist or pharmacist who can look at your skin, not for a guide.

How Strong The Evidence Is

Two papers have counted the studies rather than repeating them, and both landed in the same place. Michalek, Lelen-Kaminska and Caetano Dos Santos ran a systematic search of three literature databases under a PRISMA protocol, looking for clinical studies of peptides that stimulate extracellular matrix synthesis, the category most anti-ageing serums sell. They found 12 papers reporting 15 independent studies, which is a very small body of work for an ingredient class this widely sold.

What those 15 studies looked like

Six of the 15 used a placebo control. The other nine did not.
Double-blinding was applied in five of the 15.
Nine of the 15 were based on female-only populations.
Ten of the 15 used image-based methods to judge the result.

Their conclusion was that the literature on the topic is sparse, that the studies conducted so far have many methodological limitations, and that better planned and controlled clinical trials are needed. That review covers peptides marketed for extracellular matrix stimulation, so it does not describe every peptide sold in every serum, but it does cover most of the anti-ageing claims.

The second count comes at it from the shelf. Resende and colleagues at the University of Porto analysed the ingredient lists of 88 facial cosmetics for sensitive skin from multinational brands and found peptides in 17 percent of them, spread across seven different peptides. Three of those seven work by a neurotransmitter-inhibiting mechanism and three are signal peptides. Five of the seven had evidence supporting their use in sensitive skin, and one clinical study included volunteers who actually had sensitive skin. The authors noted that the available data sits mostly in patents and supplier brochures rather than in randomised placebo-controlled studies.

That last sentence is the one to hold on to, with the caveat that it describes the evidence for seven peptides used in sensitive-skin products specifically, not for every cosmetic peptide. A 2021 systematic review of over-the-counter anti-ageing agents in Dermatology reached a similar general position, that these products are widely available while the evidence supporting their use is often lacking.

What A Label Can Tell You

An ingredient list tells you which peptide is in the bottle. It almost never tells you how much, and that gap matters more with peptides than with most actives, because the one clinical trial on this page that reported a peptide concentration used 3 parts per million. A serum listing palmitoyl pentapeptide-4 might contain that, more, or a fraction of it, and the label reads the same either way. None of the trials on this page can be treated as evidence for a particular product unless the product matches the material and the level the trial used, and most products do not publish enough to check.

Questions a label can answer

Which peptide is present, under the ingredient name rather than the trade name.
Whether the peptide you read about in a study is the one in the bottle, once you match names like acetyl hexapeptide-3 and acetyl hexapeptide-8.
Whether the product also contains a retinoid, an acid or a high-strength vitamin C, which changes what the peptide is being credited with.
Whether a claim on the front of the box matches any study on the ingredient, or is borrowed from a study of a different delivery format such as a microneedle patch.

Buying in Vietnam adds a practical wrinkle, which is that a lot of imported skincare arrives through resellers on Shopee, Lazada and Facebook rather than through a brand's own channel, so the storage and transit history of a bottle is usually unknown. That matters more here than for a simple moisturiser, because the 2025 BioImpacts review lists instability among the formulation challenges for this class of peptide, alongside their high water solubility and low partition coefficient. A pharmacist at a chain like Pharmacity or Long Chau can read a label with you, and a dermatologist at one of the international clinics in Ho Chi Minh City or Hanoi is the right person for pigment, persistent acne or any reaction to a product.

On safety, the 2026 Current Research in Toxicology paper proposes a framework rather than reporting a verdict. It uses six bioinformatic tools to screen peptide sequences for toxin and allergen signals, it correctly identified the safety concerns for the amanitin and conotoxin peptides in its test set, and the three cosmetic peptides it ran came back showing sequence homology with skin structural proteins and none of those concerns. The authors say further testing of the framework by the cosmetic industry is needed to support it and to reveal refinements. That is a screening method that looks promising, not a safety certification any product on a shelf currently carries.

Where The Evidence Stops

Being clear about the holes is more useful than another round of claims, so here is what the studies on this page do not establish.

No trial here compares a single-peptide serum against a retinoid over the same period. The 2010 comparison used a three-product cosmetic regimen that contained a retinoid ester of its own.
The longest study cited runs 24 weeks, and that stage was a self-selected continuation cohort of 25 people per arm. Nothing here speaks to years of use.
The peptide concentration is reported in one of the clinical trials cited here, the 3 parts per million in the 2005 Robinson study. Everywhere else it is unstated, which makes matching a study to a product guesswork.
Men are barely represented. Nine of the 15 studies in the 2019 review were female-only, and every trial cited here that states the sex of its subjects enrolled women.
Where these trials name a population it is Caucasian women aged 35 to 55, Chinese subjects, or 21 Indonesian women, and several of the others do not name one at all. That is not a broad base for a product category sold worldwide.
For palmitoyl tetrapeptide-7 and acetyl octapeptide-3, PubMed searches on 5 August 2026 surfaced no placebo-controlled trial of the peptide on its own in a serum. Absence from PubMed is not proof that no research exists, because supplier testing and patent data are not indexed there, but it does mean you cannot check it.

For the individual ingredient pages with the mechanism detail, see Argireline, SNAP-8 and topical GHK-Cu, and the skincare actives guide puts the whole shelf in order.

The Short Version

A peptide serum is worth judging by the specific peptide in it, because the evidence is uneven across the names on a label.
Palmitoyl pentapeptide-4 has the largest single-ingredient trial cited here: 93 Caucasian women, 12 weeks, split-face, placebo-controlled, at 3 parts per million.
Acetyl hexapeptide-8 has a 60-subject randomised trial in Chinese subjects with a positive result over 4 weeks, and an FDA in vitro study showing that almost none of it reached below the stratum corneum in excised skin.
Copper tripeptide-1 is the only name in the table above under the 500 Dalton figure, and its randomised human trial found no objective difference against control on redness or wrinkles, alongside significantly higher patient satisfaction.
A 2019 systematic review found 15 studies in this whole category, six with a placebo control and five double-blinded.
The 2010 trial is often quoted as a cosmetic regimen matching prescription tretinoin, but at 24 weeks it only failed to detect a difference in a self-selected continuation cohort of 25 per arm, and the cosmetic arm also contained niacinamide and a retinoid ester, so it is not a peptide result.

Frequently Asked Questions

Does a peptide serum actually work?+

Some of the peptides sold in serums have placebo-controlled human trials behind them and some do not, so the answer depends on which peptide is in the bottle. A 2019 systematic review in the Australasian Journal of Dermatology looked at the peptides marketed for stimulating extracellular matrix and found 12 papers reporting 15 independent studies. Six of the 15 used a placebo control and five were double-blinded, and the authors concluded the literature is sparse and needs better planned trials. Among the peptides covered on this page, palmitoyl pentapeptide-4 has the largest placebo-controlled trial: 93 Caucasian women aged 35 to 55 ran a 12-week double-blind split-face study and the peptide side beat the plain moisturiser side for fine lines and wrinkles.

Which peptide in a serum has the most evidence behind it?+

Palmitoyl pentapeptide-4, also written pal-KTTKS and listed in PubChem under the Matrixyl trade name, has the largest placebo-controlled trial of the cosmetic peptides covered here. Robinson and colleagues ran 93 Caucasian women aged 35 to 55 through 12 weeks of a double-blind, placebo-controlled, split-face design comparing a moisturiser against the same moisturiser carrying 3 parts per million of the peptide, and the peptide side improved significantly on both image analysis and expert grading. All six authors were listed at The Procter and Gamble Company, and the trial says nothing about other skin types or about men.

Is a copper peptide serum worth it?+

The human data on copper tripeptide-1 is thinner than the marketing suggests. The randomised human trial that turns up for it gave it to patients after CO2 laser resurfacing, and 13 patients completed the study split across the two regimens. Blinded evaluators and computer analysis found no significant difference in how fast redness resolved, and no difference between groups in wrinkles or skin quality, although the patient questionnaire did show significantly higher satisfaction with overall skin quality for the copper peptide group at P equals 0.04. A 2025 review of topically applied GHK called out what it described as a surprising absence of clinical studies using GHK-Cu and Pal-GHK, while noting that cell studies support the ingredient.

Is an argireline serum the same as botox in a bottle?+

No, and the penetration data is the reason to be careful with that comparison. A US FDA laboratory applied an oil-in-water emulsion containing 10 percent acetyl hexapeptide-8 to human cadaver skin and hairless guinea pig skin in vitro diffusion cells for 24 hours. Most of it washed off the surface. What stayed in the skin sat mostly in the stratum corneum at 0.22 percent of the applied dose in human skin, about 0.01 percent reached the epidermis, and none was detected in the dermis or in the fluid underneath. A separate randomised trial in 60 Chinese subjects did report a measurable anti-wrinkle effect over 4 weeks, so the surface result and the penetration result both stand and neither one cancels the other.

Should I use a peptide serum or retinol?+

The closest thing to a direct answer is a 2010 British Journal of Dermatology trial of 196 women, where a cosmetic regimen beat prescription 0.02 percent tretinoin on wrinkle appearance at 8 weeks with better tolerability, and no significant difference was detected at 24 weeks, in a self-selected continuation cohort of 25 per arm. The catch is that the cosmetic arm was not a peptide serum. It contained 5 percent niacinamide, peptides, antioxidants and 0.3 percent retinyl propionate, which is itself a vitamin A ester, so the trial cannot tell you what the peptides contributed. It is also worth knowing how small the peptide evidence base is: a 2019 systematic review counted 15 clinical studies across the whole extracellular matrix peptide category. A dermatologist or pharmacist is the right person to ask about your own skin.

References

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. 12 papers, 15 independent studies, 6 placebo-controlled, 5 double-blinded, 9 female-only. PMID 30941744
Robinson LR, Fitzgerald NC, Doughty DG, Dawes NC, Berge CA, Bissett DL. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-160. 93 Caucasian women aged 35 to 55, 12 weeks, split-face, 3 ppm pal-KTTKS. All authors at The Procter and Gamble Company. PMID 18492182
Aruan RR, Hutabarat H, Widodo AA, Firdiyono MTCC, Wirawanty C, Fransiska L. 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. 21 Indonesian women aged 26 to 55 across three groups, 8 weeks, Jakarta. PMID 36909866
Wang Y, Wang M, Xiao S, Pan P, Li P, Huo J. 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. 60 subjects randomised 3:1, 4 weeks, peri-orbital. PMID 23417317
Raikou V, Varvaresou A, Panderi I, Papageorgiou E. The efficacy study of the combination of tripeptide-10-citrulline and acetyl hexapeptide-3. A prospective, randomized controlled study. J Cosmet Dermatol. 2017;16(2):271-278. 24 volunteers across four groups, 60 days, Athens. PMID 28150423
Kraeling ME, Zhou W, Wang P, Ogunsola OA. In vitro skin penetration of acetyl hexapeptide-8 from a cosmetic formulation. Cutan Ocul Toxicol. 2015;34(1):46-52. US FDA CFSAN Division of Toxicology. In vitro diffusion cells, hairless guinea pig and human cadaver skin, 10 percent emulsion at 2 mg per square centimetre for 24 hours. PMID 24754410
Bos JD, Meinardi MM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Exp Dermatol. 2000;9(3):165-169. A proposed rule argued from contact allergens, topical dermatology drugs and transdermal delivery systems. PMID 10839713
Billich A, Vyplel H, Grassberger M, Schmook FP, Steck A, Stuetz A. Novel cyclosporin derivatives featuring enhanced skin penetration despite increased molecular weight. Bioorg Med Chem. 2005;13(9):3157-3167. In vitro, rat and human skin, prodrugs of 1200 to 1600 Da. Novartis. PMID 15809151
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. 13 patients completed across two arms, circumoral resurfacing, 12-week assessment. PMID 16847171
Mortazavi SM, Mohammadi Vadoud SA, Moghimi HR. Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective. Bioimpacts. 2025;15:30071. Review. Reports a surprising absence of clinical studies using GHK-Cu and Pal-GHK. PMID 39963574
Avcil M, Akman G, Klokkers J, Jeong D, Çelik A. Efficacy of bioactive peptides loaded on hyaluronic acid microneedle patches: A monocentric clinical study. J Cosmet Dermatol. 2020;19(2):328-337. Five-component microneedle patch, 12 weeks. Authors affiliated with the product companies. PMID 31134751
Shin JY, Han D, Yoon KY, Jeong DH, Park YI. Clinical Safety and Efficacy Evaluation of a Dissolving Microneedle Patch Having Dual Anti-Wrinkle Effects With Safe and Long-Term Activities. Ann Dermatol. 2024;36(4):215-224. Dissolving hyaluronic acid microneedle patch containing acetyl octapeptide-3, 24 healthy subjects, placebo patch on the opposite eye, 28 days. Four of the five authors listed at the patch manufacturer. PMID 39082657
Yang F, Zhang X, Wang H, et al. Comprehensive evaluation of the efficacy and safety of a new multi-component anti-aging topical eye cream. Skin Res Technol. 2024;30(7):e13790. Four-part active complex including palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7, 12 weeks. First authors at the manufacturer. PMID 38932444
Fu JJ, Hillebrand GG, Raleigh P, et al. A randomized, controlled comparative study of the wrinkle reduction benefits of a cosmetic niacinamide/peptide/retinyl propionate product regimen vs. a prescription 0.02% tretinoin product regimen. Br J Dermatol. 2010;162(3):647-654. 196 women, 99 cosmetic and 97 tretinoin, 8 weeks with cohorts of 25 continuing to 24 weeks. Lead author at The Procter and Gamble Company. PMID 20374604
Resende DISP, Ferreira MS, Sousa-Lobo JM, Sousa E, Almeida IF. Usage of Synthetic Peptides in Cosmetics for Sensitive Skin. Pharmaceuticals (Basel). 2021;14(8):702. Ingredient analysis of 88 facial cosmetics for sensitive skin from multinational brands. PMID 34451799
Imhof L, Leuthard D. Topical Over-the-Counter Antiaging Agents: An Update and Systematic Review. Dermatology. 2021;237(2):217-229. PMID 32882685
Bjerke DL, Li J, Gao Y, Hu P, Lintner K, Hakozaki T. A framework for the safety evaluation of peptides in cosmetics. Curr Res Toxicol. 2026;10:100291. Six bioinformatic tools tested on seven peptides including amanitin alpha and conotoxin ArlB. Authors at The Procter and Gamble Company and KAL'IDEES SAS. PMID 41953401
Molecular weights and the shared compound record for acetyl hexapeptide-3, acetyl hexapeptide-8 and Argireline read from the PubChem compound records (CIDs 71587328, 90479646, 10231864, 11950477, 10078408, 9897237, 71587772 and 76283482) on 5 August 2026. pubchem.ncbi.nlm.nih.gov
Search counts quoted for acetyl octapeptide-3 and palmitoyl tetrapeptide-7 were run against the PubMed database through the NCBI E-utilities interface on 5 August 2026, using each ingredient name as a plain search term with no field restriction. NCBI E-utilities

Every figure on this page was read from the abstract of the paper it is attributed to. Where a study measured cells, excised skin or animal skin rather than living human skin, the sentence using it says so.