Pentapeptide-18 vs Acetyl octapeptide-3
It is a cream ingredient sold as a Botox alternative for expression lines. Two small studies of 20 people each had no comparison group, so the proof is weak. 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.
Both sit at grade C: animal and cell studies. Neither is FDA approved.
Evidence
CAnimal and cell studies
CAnimal and cell studies
Human studies cited
Animal or cell studies cited
Why the grade
The human evidence is two small uncontrolled studies: a 20-volunteer, two-month test of pentapeptide-18 creams at three strengths, in which only the strongest reduced measured wrinkle length, and an eight-week test in 20 women of a cream that also contained retinol. Neither had a vehicle or placebo control, and the manufacturer has not published its own trial data. Uncontrolled series put it at C for expression lines.
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
Pentapeptide-18 is a cosmetic ingredient, sold under the trade name Leuphasyl. Cosmetic ingredients in the United States are not reviewed or approved by the FDA before sale, so there is no FDA approval to cite for or against it.
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
Pentapeptide-18 is sold as a topical alternative to botulinum toxin that softens expression lines, usually paired with acetyl hexapeptide-8 (Argireline).
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
Two small uncontrolled studies in 20 volunteers each report shorter or fewer wrinkles after weeks of use, one of them with retinol in the same cream, which is grade C support at best.
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