Leuphasyl (Pentapeptide-18)
Leuphasyl is a cosmetic peptide made of five amino acids that resembles the body's own natural painkilling substances. It is studied as a cream ingredient that relaxes the facial expression muscles and reduces wrinkles, especially together with Argireline.
Tyr-D-Ala-Gly-Phe-Leu — 5 aa, enkephalin-like structure. A mimetic of endogenous enkephalins.
A topical muscle relaxant acting through calcium channels — a mechanism complementary to Argireline. Wrinkle reduction of −11.64% over 28 days (0.05%). Often used in combination with Argireline and SNAP-8 for a triple synergistic effect.
Binds to enkephalin receptors on the presynaptic membrane → blocks voltage-gated Ca²⁺ channels → ↓Ca²⁺ influx → ↓acetylcholine release → ↓contraction of facial expression muscles. The target differs from Argireline (SNARE) — a complementary mechanism.
Studies used 3–5% in a serum or emulsion twice a day for 28 days or longer, often in combination with other peptides.
Level B Human observational data. There are studies in humans, but they are small, uncontrolled, or cohort studies. The data are encouraging but need confirmation. Clinical data come mainly from combinations. Few standalone RCTs.
⚠️ Cosmetic ingredient. The number of standalone placebo-controlled RCTs is limited.
Research peptides are laboratory reagents (Research Use Only). They are not medicines and are not intended for use in humans or animals.