Snap-8 is a synthetic octapeptide, Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2, acetylated at the N-terminus and amidated at the C-terminus. Its sequence reproduces residues 12–19 of SNAP-25 (synaptosomal-associated protein of 25 kDa) and extends the earlier N-terminal acetyl hexapeptide (residues 12–17) by two residues. Its INCI names are Acetyl Octapeptide-3 and Acetyl Glutamyl Heptapeptide-3.

SNAP-25 is a component of the SNARE complex, the four-helix bundle formed with syntaxin and synaptobrevin that drives regulated vesicle fusion and exocytosis. Peptides patterned after the SNAP-25 N-terminal domain have been reported to compete with the native protein for incorporation into the SNARE complex, inhibiting complex assembly and calcium-dependent exocytosis in chromaffin cell models.

Snap-8 is cited in research on SNARE complex assembly, regulated exocytosis in neuroendocrine cell models, and peptide modulators of protein–protein interactions. It is also studied as a cosmetic peptide ingredient in formulation science, including stability and in vitro permeation testing of formulations. The methionine residue is susceptible to oxidation.

Research use only. This material is sold for in-vitro laboratory research and development purposes exclusively. It is not a drug, food, or dietary supplement, has not been evaluated by the FDA, and must not be used in humans or animals.