Leuphasyl is the trade name for pentapeptide-18, a lab-made five-amino-acid peptide used in skin care for expression lines. It is described as reducing the release of the nerve signal that makes muscles contract. We found no published placebo-controlled human trial of it on its own.
Also known as: Leuphasyl, pentapeptide-18.
There is no standard strength, and the studies below do not give a concentration in the abstract.
Skin-care peptides are sold as cosmetic ingredients. FDA does not approve cosmetics before they go on the market. FDA says a product that only moisturizes so lines look less noticeable is a cosmetic, but a product intended to remove wrinkles or increase the skin's production of collagen is a drug or a medical device, even if it is sold as a cosmetic.
Most of the published work is computer modeling and cell tests. Two 2026 studies from the same Istanbul group modeled how pentapeptide-18 binds proteins linked to skin aging (Akhan 2026a), and found it was not toxic to skin cells in a dish at up to 1 mg/mL (Akhan 2026b). The only human data we found come from a study co-authored by company employees (Pawłowska 2024) that tested creams combining retinol and pentapeptide-18 in fat nanoparticles: volunteers had less oil on the skin and fewer wrinkles, but the abstract does not say how many people took part, and retinol was in the same cream, so the peptide's own effect cannot be separated.
A 2026 review of cosmetic peptides (Yi) notes that many trials are small, short, sponsored by industry or use several ingredients.
We could not find a published half-life or time to peak for pentapeptide-18. It is applied to the skin, and the studies we found measured the skin, not levels in the blood, so we do not list one.
How Dose Track handles peptides · Reconstitution calculator · Half-life calculator