Acetyl hexapeptide-8 vs Acetyl octapeptide-3
It is a cream ingredient sold as a needle-free way to smooth expression lines. Two small trials disagreed: one showed less wrinkling, one showed none. A face-cream ingredient sold to smooth lines around the eyes and forehead. It has not been properly tested on its own; one 24-person study used a mixed product.
Acetyl hexapeptide-8 has the stronger evidence, grade B (some human evidence) against grade C for Acetyl octapeptide-3. Neither is FDA approved.
Evidence
BSome human evidence
CAnimal and cell studies
Human studies cited
Animal or cell studies cited
Why the grade
For wrinkle reduction there is one randomized placebo-controlled trial in 60 Chinese adults showing a benefit, a 19-person split-face double-blind study showing none, a 26-patient uncontrolled series and the manufacturer's original volunteer study. Skin penetration work in human and animal skin finds very little of the peptide reaches the dermis, which leaves the mechanism in doubt. Small samples and conflicting results keep this at B.
The only peer-reviewed human study found that tests a product containing SNAP-8 is a 2024 split-face study in 24 people, in which a microneedle patch carrying SNAP-8 together with other actives was compared with a plain hyaluronic acid patch for 28 days. SNAP-8 has not been tested on its own against placebo, and the claim that it beats Argireline comes from the manufacturer. That is grade C.
FDA
Cosmetic ingredient
Acetyl hexapeptide-8 (Argireline) is a cosmetic ingredient, and the FDA does not approve cosmetic ingredients before sale; products containing it are regulated as cosmetics so long as they claim only to improve appearance. It is not an approved drug for any use.
Cosmetic ingredient
Acetyl octapeptide-3 (SNAP-8) is a cosmetic ingredient. The FDA does not approve cosmetic ingredients before sale and regulates products containing it as cosmetics provided they claim only to improve appearance; it is not an approved drug for any use.
Sold for
Argireline is marketed as a needle-free alternative to Botox that relaxes expression lines when applied as a cream or serum.
SNAP-8 is sold as a longer, stronger version of Argireline that relaxes expression lines around the eyes and forehead when applied topically.
Studies say
One small randomized trial found a measurable reduction in eye-area wrinkles and another found none, while penetration studies show almost none of the peptide reaches the muscle layer, so the evidence supports a modest surface effect at best (grade B).
The mechanism is borrowed from Argireline and the clinical support is one 24-person study of a microneedle patch that mixed SNAP-8 with other actives, which is too little to say SNAP-8 itself reduces wrinkles (grade C).
Class
Neurotransmitter-inhibiting peptide
Neurotransmitter-inhibiting peptide
Route
Topical
Topical