Compound family

Cosmetic peptides

In one sentenceThe two peptides most people have actually applied to their face. One randomised trial each, both run by the companies that sell them.
Compounds2
Best gradeC Argireline
Approved medicines0 of 2
Prohibited in sport0 of 2

What this family is

Argireline (acetyl hexapeptide-8) and Matrixyl (palmitoyl pentapeptide-4) are the two best-known peptides in skincare, and between them they illustrate how cosmetic-ingredient evidence is made. Argireline is a six-residue peptide copying the end of SNAP-25 — the protein botulinum toxin cuts — and is sold as a topical alternative to injections. Matrixyl is a five-residue fragment of type I collagen with a palmitic acid tail attached so it can cross the skin barrier, sold to stimulate collagen production.

Each has exactly one supporting randomised trial. Argireline's is a 60-person, four-week study that reported reduced periorbital roughness and a 48.9%-versus-0% subjective anti-wrinkle rate — and was published three times in 2013 by the same group, which makes the literature look three times larger than it is. Matrixyl's is a 93-woman, twelve-week, split-face study from Procter & Gamble that found significant wrinkle improvement by both instrumental and expert-grader analysis. Matrixyl's trial is the better one; both are graded C, because one industry trial is evidence and not establishment.

Both are lawful cosmetic ingredients in every region LYO covers, neither is a medicine, neither has a safety signal, and neither has been compared with the injectable or prescription treatments they are marketed against. The injectable copper peptides GHK-Cu and AHK-Cu are kept with the tissue-repair peptides, where their injected grey-market use belongs.

Grade counts across the family: 0 × A · 0 × B · 2 × C · 0 × D. The best grade here, C, means weak human evidence. How LYO grades →

The compounds, graded

Every member with its best-supported outcome grade, human-trial count and regulatory status. Each opens the full evidence page.

Argireline

C

A six-residue cosmetic peptide sold as a topical alternative to botulinum toxin. One small randomised trial supports it — published three times by the same group.

Human trials1 small RCT (n=60, 4 weeks)
StatusCosmetic ingredient

Matrixyl

C

A palmitoylated five-residue peptide from collagen, and the best-evidenced cosmetic peptide here: one 93-person split-face trial run by its user.

Human trials1 split-face RCT (n=93, 12 weeks)
StatusCosmetic ingredient

Questions

Which cosmetic peptide has the best evidence?
Matrixyl, on trial design: twelve weeks, 93 people, split-face control, two independent measurement methods. Argireline's trial is four weeks in 60 people. Both are single, sponsor-run studies.
Can a peptide applied to skin replace botulinum toxin injections?
No trial has compared them. Argireline shares a molecular target with botulinum toxin in laboratory systems; whether a hexapeptide in a serum reaches motor nerve terminals is unanswered.
Are cosmetic peptides regulated?
As cosmetics, not medicines — no pre-market approval, and no authorised health claim in the EU. A product that claimed to treat a condition rather than improve appearance would be making a medicinal claim.

Written and maintained by LYO Research — how pages are written and checked. Reviewed 29 October 2026. Grades count human evidence only. Not medical advice. Correct this page →