Snap-8

Snap-8, or acetyl octapeptide-3, is a synthetic eight-residue cosmetic peptide, Ac-EEMQRRAD-NH2, modeled on the N-terminal region of the SNARE protein SNAP-25. It is studied mainly in vitro and in cosmetic formulation research.

Last reviewed 2026-10-25 by the PeptideWiki editorial team. Editorial policy.

Overview

Snap-8 is a short synthetic peptide developed for cosmetic research, listed under the INCI name acetyl octapeptide-3. It is an elongated relative of acetyl hexapeptide (Ac-EEMQRR-NH2), a well-known cosmetic peptide, with two additional residues at the C-terminus. Both are designed to resemble part of the N-terminal region of SNAP-25, one of the proteins that make up the SNARE complex involved in neurotransmitter release.

The intended research context is expression lines in skin. The hypothesis is that a SNAP-25-like peptide could interfere modestly with SNARE complex assembly, reducing the release of acetylcholine at nerve endings in the way that, by a completely different mechanism, botulinum toxin does. Evidence for this comes largely from in-vitro assays and cosmetic studies, and independent peer-reviewed controlled human data are limited.

Structure

Snap-8 is the octapeptide Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2 (Ac-EEMQRRAD-NH2), with an acetylated N-terminus and an amidated C-terminus, both modifications intended to improve stability against exopeptidases. The first six residues match acetyl hexapeptide, and the added Ala-Asp extends the SNAP-25-derived sequence. It contains one methionine, which is susceptible to oxidation, and a glutamine and an aspartate that can be sites of degradation. Material is commonly supplied as an acetate or TFA salt.

Mechanism

The proposed mechanism is competitive interference with SNARE complex formation. SNAP-25, syntaxin and synaptobrevin assemble into a complex that drives fusion of neurotransmitter vesicles with the cell membrane. A peptide mimicking part of SNAP-25 is hypothesized to compete for binding positions in the complex, destabilizing it and reducing vesicle release. In-vitro studies with related acetyl hexapeptides have reported reduced catecholamine release in cultured cells. Whether a topically applied peptide reaches nerve terminals in skin in meaningful amounts is not established, so the mechanism in vivo remains hypothetical.

Research

In-vitro SNARE studies

The main mechanistic support comes from in-vitro experiments on SNARE complex assembly and on neurotransmitter release from cultured cells, most of it conducted with the shorter acetyl hexapeptide. Data specific to the octapeptide are fewer and frequently come from ingredient-development work rather than independent academic studies. These assays show a plausible biochemical interaction but do not establish an effect in living skin.

Cosmetic formulation studies

Small studies of topical formulations containing SNAP-25-derived peptides have assessed the appearance of facial expression lines using imaging and profilometry. Results are generally reported as modest changes in appearance-related measures. Many such studies are short, small and not independently replicated, and some are not published in peer-reviewed journals. They are cosmetic, not therapeutic, investigations. Vehicle effects, such as moisturization from the base cream, can also influence appearance measures, so vehicle-controlled designs are important.

Skin penetration

A key open question for all SNAP-25 mimetic peptides is penetration. Charged peptides of this size generally cross the outer skin barrier poorly, and research has examined penetration enhancers, delivery vehicles and modified analogues. Penetration data are limited, and claims about effects on deeper structures should be viewed cautiously. In-vitro penetration studies on excised skin, where available, vary in method and are not always comparable. Without reliable penetration data, the link between in-vitro SNARE assays and any effect in skin remains uncertain.

Evidence quality

Snap-8 has a modest evidence base drawn mainly from in-vitro work and cosmetic studies, with little independent peer-reviewed human research. It is not a drug and has not been the subject of clinical trials for any medical condition. It is best regarded as a cosmetic research peptide with a hypothesized, partly supported, mechanism. Claims of botulinum-toxin-like effects are not supported by comparative data.

Regulatory status

Snap-8 is not approved by the FDA as a drug for any use. Acetyl octapeptide-3 is used as a cosmetic ingredient, and cosmetic products may not make claims to treat or prevent disease. It is not a botulinum toxin and is not regulated as one. For sport, check the current WADA Prohibited List.

Status changes often. See the regulatory tracker for dated updates.

Quality and identity testing

A good certificate of analysis should confirm identity by mass spectrometry, with the observed mass matching the expected mass shown on this page for the acetylated, amidated octapeptide, and report HPLC purity with the chromatogram. Check that both terminal modifications are present: a missing acetyl group shifts the mass by 42 Da and a free acid in place of the amide by about 1 Da, which can be hard to resolve on low-resolution instruments. The methionine is oxidation-prone, so a +16 Da peak should be looked for and reported. Confusion with the shorter acetyl hexapeptide is another pitfall, as is an unstated counter-ion.

Open Snap-8 in the sequence analyzer to see the expected [M+H]⁺ and multiply charged ions for an MS identity check (set the N-acetyl, amide and disulfide options to match).

For a walkthrough of each section of a certificate, see how to read a COA.

Storage and stability

Store lyophilized Snap-8 sealed at -20 °C, protected from light, moisture and air, and equilibrate to room temperature before opening. The methionine residue can oxidize, so minimize headspace and consider inert-gas purging for long-term storage. In solution, keep refrigerated for short-term lab use, aliquot for frozen storage, and avoid repeated freeze-thaw cycles. Glutamine and aspartate residues can degrade over time in aqueous solution, especially at extreme pH.

Download the Snap-8 data sheet (PDF): sequence, masses, expected MS ions and handling on one printable page.

Latest research

Frequently asked questions

Related compounds

• GHK-Cu

  GHK-Cu is the copper(II) complex of GHK (glycyl-histidyl-lysine), a tripeptide found in human plasma. It is widely used as a cosmetic ingredient and studied in cell, animal and small human skin studies.

• VIP (vasoactive intestinal peptide)

  Vasoactive intestinal peptide (VIP) is a 28-amino-acid neuropeptide of the secretin-glucagon family that acts on VPAC1 and VPAC2 receptors. It regulates smooth muscle, secretion and immune function, and synthetic VIP (aviptadil) has been studied clinically.

• Oxytocin

  Oxytocin is a nine-amino-acid peptide hormone made in the hypothalamus and released from the posterior pituitary, with a disulfide-bridged ring structure. It regulates uterine contraction and milk ejection, and synthetic oxytocin (Pitocin) is FDA-approved.

References

1. PubMed: all indexed literature on Snap-8
2. ClinicalTrials.gov: registered studies mentioning Snap-8