Acetyl Hexapeptide-8 (Argireline)

What acetyl hexapeptide-8 is

Acetyl hexapeptide-8 is a short, lab-made chain of six amino acids used as a cosmetic ingredient. Its sequence is Ac-Glu-Glu-Met-Gln-Arg-Arg-NH2, with a chemical cap on each end. [1][2] It was designed to copy a piece of SNAP-25, a protein nerve cells use to release chemical signals. [3]

Names matter here, because several different labels point to the same molecule:

A finished serum that lists this ingredient is a different thing again: it also contains water, preservatives and often other actives. See ingredient evidence vs finished-product evidence.

Evidence labels on this page: promising but limited (small trials, often by people linked to the ingredient's makers), preclinical (cells/animals only), marketing claim (a statement not shown by proper studies) and insufficient evidence.

The "botox-like" idea

The proposal is that the peptide interferes with the release of the signal that makes a muscle contract, so expression lines soften. The original 2002 paper reported that the peptide blocked this signal release in lab tests, with much lower efficacy than botulinum toxin. [2] Whether it does this in a person who rubs it on the skin is a separate question; see peptides marketed as neurotransmitter-modulating.

What studies in people show

• 2002 volunteer study (promising but limited). An emulsion reported as containing 10% of the hexapeptide reduced wrinkle depth by up to 30% over 30 days in women volunteers. [2]
• 2013 randomized trial (promising but limited). In 60 people, treatment or placebo was applied twice daily around the eyes for 4 weeks, in a 3:1 ratio. Overall anti-wrinkle efficacy by subjective grading was 48.9% with the peptide versus 0% with placebo, and instrument measures of roughness fell only in the peptide group. [5]
• 2017 randomized study (promising but limited). In 24 volunteers over 60 days, the authors concluded it showed anti-wrinkle activity; the other ingredient tested alongside it was tripeptide-10 citrulline. [6]
• 2026 serum studies (finished product, not the ingredient alone). A serum containing this peptide plus other actives improved wrinkle scores in two clinical studies of 50 and 42 people; the authors are employees of L'Oréal research centers, and the other ingredients cannot be separated out. [7]
• Blepharospasm pilot. A small randomized trial in 24 people with eyelid spasms found no significant adverse events and only a trend toward longer symptom control after botulinum toxin injections (3.7 versus 3.0 months). [8] This is not evidence that it replaces injections.

A 2025 review of this literature says none of the application studies it covered confirmed an effect on muscle contraction, and that the effects may come from the skin surface instead. [3]

Does it reach the muscle?

FDA laboratory scientists tested a 10% emulsion on human skin and animal skin in diffusion cells. After 24 hours most of the peptide washed off the surface, about 0.22% stayed in the outer skin layer of human skin, and none was detected in the dermis or the fluid underneath. [9] A 2025 review concluded that the ability of the peptide to reach the nerve-muscle junction remains uncertain. [10]

Related guides

What are cosmetic peptides? and peptides in topical formulations explain delivery limits. For practical skin care, see skin care basics.