Identity a synthetic hexapeptide (6 amino acids, < 40 aa → peptide), N-acetylated, patterned on the N-terminal end of SNAP-25 (a SNARE-complex protein and a target of botulinum toxin). Introduced ~2001 by Lipotec (now Lubrizol); now genericised and widely used. ## Development & history - Developed by the Spanish biotech Lipotec and introduced around 2001; the first efficacy report was Blanes-Mira et al. 2002 (Int J Cosmet Sci). It was marketed from the outset on a "topical botox" analogy to botulinum toxin.
- After its patents lapsed it was genericised and is now widely synthesised. Lipotec was acquired by Lubrizol (2012), which holds the Argireline® trade name. It has only ever been a cosmetic ingredient — never developed as a drug. ## Mechanism (as proposed) Ac-EEMQRR-NH₂ mimics the N-terminal of SNAP-25 and is proposed to compete for SNARE-complex assembly, attenuating Ca²⁺-dependent acetylcholine exocytosis at the neuromuscular junction and thereby reducing contraction of facial-expression muscles. This differs fundamentally from botulinum toxin (which enzymatically cleaves SNAP-25 for an irreversible, injected effect). The mechanism is largely characterised in vitro; whether enough peptide crosses intact skin at cosmetic concentrations to act on the NMJ is doubtful.