Peptides for skin: what the research shows
- 9 compounds
- Evidence level on each
- Last reviewed Nov 5, 2026
What they are
“Peptides for skin” usually means short lab-made chains of amino acids added to creams and serums. Some are meant to relax expression lines (Argireline, SNAP-8, Syn-Ake, pentapeptide-18), some to signal collagen (Pal-GHK, Syn-Coll), some to carry copper (GHK-Cu, AHK-Cu), and some to lighten skin (nonapeptide-1). They’re sold as cosmetic ingredients, not approved drugs.
This page covers the peptides most often sold for wrinkles, skin tone and hair: Argireline, SNAP-8, Syn-Ake, pentapeptide-18, Pal-GHK, Syn-Coll, nonapeptide-1, and the copper peptides AHK-Cu and GHK-Cu. Here is what each one is, what it has been studied in, and what the studies found.
The compounds
Argireline (acetyl hexapeptide-8)
A lab-made six-amino-acid peptide, also listed as acetyl hexapeptide-3, designed to copy part of SNAP-25, a protein nerves need to signal muscles. It’s sold as a cream ingredient for expression lines.
Studied inCellAnimalHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025). A cosmetic safety panel found it safe at up to 0.005% and said there wasn’t enough data to judge higher concentrations (Johnson et al., 2025).
In 60 people, 4 weeks of twice-daily use around the eyes improved wrinkles in 48.9% on Argireline versus none on placebo (Wang et al., 2013). In 19 women who used a serum with it on one side of the face and without it on the other, the Argireline side did no better (Henseler et al., 2023). In a lab test on donor skin, almost all of a 10% cream stayed on the surface; 0.01% reached the outer living layer and none reached the deeper skin (Kraeling et al., 2015).
Full summary in progress.
SNAP-8 (acetyl octapeptide-3)
A longer, eight-amino-acid relative of Argireline, made for the same purpose.
Studied inHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
We haven’t found a study of SNAP-8 on its own. In 24 people, a microneedle patch containing it plus two other actives improved eye wrinkles more than a plain patch (Shin et al., 2024), so the result can’t be credited to SNAP-8 alone.
Full summary in progress.
Syn-Ake
A small lab-made peptide (dipeptide diaminobutyroyl benzylamide diacetate) sold for expression lines.
Studied inCellHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
Its own research is computer modeling and cell tests, which found no cell damage at the doses tested (Gok et al., 2024). In people it has only been studied inside a serum that also contained Argireline, niacinamide and other actives, with no placebo group (Zhu et al., 2026).
Full summary in progress.
Pentapeptide-18 (Leuphasyl)
A lab-made five-amino-acid peptide sold for expression lines, often paired with Argireline.
Studied inCell
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
Its published research is computer modeling and cell tests; it didn’t harm skin cells at the concentrations tested (Akhan et al., 2026). We haven’t found a published study in people.
Full summary in progress.
Pal-GHK (palmitoyl tripeptide-1)
GHK, the copper peptide’s amino-acid chain, without copper and with a fatty acid attached to help it enter skin. It’s one of the two peptides in Matrixyl 3000.
Studied inAnimalHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
In 3 women, Pal-GHK from a serum was found throughout the skin’s outermost layer (Trzaska et al., 2026). In stressed mice, a mix of Pal-GHK, EGCG and biotin improved hair regrowth (Zheng et al., 2026). We haven’t found a published study of its effect on skin in people.
Full summary in progress.
Syn-Coll (palmitoyl tripeptide-5)
A lab-made three-amino-acid peptide with a fatty acid attached, sold to support collagen.
Studied inHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
We haven’t found a study of Syn-Coll on its own. In a 12-week study without a placebo group, microneedle patches containing it, SNAP-8 and other actives were followed by a 25.8% decrease in fine lines (Avcil et al., 2020).
Full summary in progress.
Nonapeptide-1
A lab-made nine-amino-acid peptide used in skin-lightening products.
Studied inHuman
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
We haven’t found a study of it on its own. In 46 people with melasma, a cream containing it and other lighteners was not significantly better than sunscreen alone on melasma scores (Chatterjee et al., 2021).
Full summary in progress.
A copper peptide (alanine-histidine-lysine bound to copper), a close relative of GHK-Cu, sold mainly for hair.
Studied inCell
Status: Not an approved drug; sold as a cosmetic ingredient. Cosmetic ingredients don’t need FDA approval (FDA, 2025).
In the lab, it lengthened human hair follicles kept alive in culture and helped the cells at their base grow (Pyo et al., 2007). We haven’t found a published study of hair growth in people.
A copper-binding peptide found naturally in blood, best known from skin-care research.
Studied inCellAnimalHuman
Status: Not approved as a drug; used in cosmetics.
Wound-healing studies in animals and small cosmetic studies on human skin, summarized in a review by the peptide’s discoverer (Pickart et al., 2015). We haven’t found a published human trial of injected GHK-Cu.
Before you compare them
- Most have no study of their own. SNAP-8, Syn-Ake, Syn-Coll and nonapeptide-1 were studied in people only inside products with several active ingredients, so a result can’t be pinned on the peptide.
- Getting into the skin is the hard part. In a lab test on donor skin, almost all Argireline stayed on the surface and none reached the deeper skin (Kraeling et al., 2015).
- Cosmetic, not drug. Cosmetic ingredients don’t need FDA approval (FDA, 2025), and safety reviews cover them as used in skin care, at low strengths: Argireline was judged safe at up to 0.005% (Johnson et al., 2025).
- Injecting them hasn’t been studied in people. See the questions below.
New to reading studies? Our guide to how to read a peptide study explains what cell, animal and human evidence can and can’t tell you.
Questions
What is the best peptide for the skin?
No study has compared them head to head. Argireline has the most human data, and it’s mixed: in 60 people it improved eye wrinkles in 48.9% versus none on placebo (Wang et al., 2013), but in 19 women who used it on one side of the face, that side did no better than the other (Henseler et al., 2023).
Do peptides actually work for wrinkles?
A little, on average. A 2026 review of 19 randomized trials with 1,341 people found a modest effect on wrinkles, driven mostly by peptides taken by mouth rather than applied to skin; effects on elasticity were inconsistent (Nukaly et al., 2026).
Which is better, retinol or peptides?
We haven’t found a trial comparing any peptide on this page with retinol, so there’s no evidence either way.
What does a copper peptide do?
GHK-Cu, the best known, has been studied mostly for wound healing in animals and in small cosmetic studies, summarized by the scientist who discovered it (Pickart et al., 2015). AHK-Cu lengthened human hair follicles in the lab (Pyo et al., 2007), but we haven’t found a hair study of it in people.
What is the disadvantage of peptides?
Mainly getting them where they’re supposed to work: most of an Argireline cream stays on the skin’s surface (Kraeling et al., 2015). Products also mix several actives, so it’s hard to tell what any one peptide does, and safety reviews cover low cosmetic strengths only (Johnson et al., 2025).
Can skin peptides be injected?
We haven’t found a published study of any of these peptides injected into people. In rats, Argireline injected under the skin produced no detectable effect on collagen (Acuner et al., 2026). Cosmetic safety reviews cover skin care products, not injections (Johnson et al., 2025).
Sources
- Wang Y, 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):147-53. PubMed 23417317
- 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. PubMed 38024099
- Kraeling ME, et al. In vitro skin penetration of acetyl hexapeptide-8 from a cosmetic formulation. Cutan Ocul Toxicol. 2015;34(1):46-52. PubMed 24754410
- Johnson W Jr, et al. Safety assessment of acetyl hexapeptide-8 amide as used in cosmetics. Int J Toxicol. 2025;44(2 Suppl):54S-63S. PubMed 40673537
- Blanes-Mira C, et al. A synthetic hexapeptide (Argireline) with antiwrinkle activity. Int J Cosmet Sci. 2002;24(5):303-10. PubMed 18498523
- U.S. Food and Drug Administration. FDA authority over cosmetics: how cosmetics are not FDA-approved, but are FDA-regulated. Content current as of November 18, 2025. FDA page
- Shin JY, et al. 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):215-24. PubMed 39082657
- Gok B, et al. Anti-aging activity of Syn-Ake peptide by in silico approaches and in vitro tests. J Biomol Struct Dyn. 2024;42(10):5015-29. PubMed 37349941
- Zhu M, et al. The effect of a serum containing acetyl hexapeptide-8, dipeptide diaminobutyroyl benzylamide diacetate and gluconolactone on skin biomarkers, wrinkles and skin texture: ex vivo and clinical studies. Int J Cosmet Sci. 2026;48(5):913-25. PubMed 41668671
- Akhan D, et al. Integrative in silico and in vitro evaluation of Vialox and Leuphasyl pentapeptides for antiaging applications. Chem Biodivers. 2026;23(5):e02546. PubMed 42116636
- Trzaska AH, et al. Permeation behaviour of cosmetic actives into the human stratum corneum. Int J Pharm. 2026;705:127447. PubMed 42790608
- Zheng X, et al. EGCG-Biotin-Pal-GHK composition modulates TGF-β and BMP pathways in scalp microenvironment for treating stress-induced alopecia. Eur J Pharmacol. 2026;1032:179217. PubMed 42575238
- Avcil M, et al. Efficacy of bioactive peptides loaded on hyaluronic acid microneedle patches: a monocentric clinical study. J Cosmet Dermatol. 2020;19(2):328-37. PubMed 31134751
- Chatterjee M, et al. A randomized controlled pilot study of a proprietary combination versus sunscreen in melasma maintenance. Indian J Dermatol Venereol Leprol. 2021;88(1):51-8. PubMed 34379946
- Pyo HK, et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res. 2007;30(7):834-9. PubMed 17703734
- Pickart L, et al. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. Biomed Res Int. 2015;2015:648108. PubMed 26236730
- Nukaly HY, et al. Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials. Front Med (Lausanne). 2026;13:1618306. PubMed 41924746
- Acuner B, et al. Effects of botulinum toxin type A and Argireline on dermal collagen remodeling and skin biology in a flap model. Aesthetic Plast Surg. 2026. PubMed 42675285
Last reviewed Nov 5, 2026 by Reed Calder. Nothing here is medical advice; see our medical disclaimer. Found a mistake? Email editors@peptideresearchstudy.com.