SNAP-8 (Acetyl Octapeptide-3): a short, honest reference

What Acetyl Octapeptide-3 is

SNAP-8 is a trade name; Acetyl Octapeptide-3 is the INCI name and the one that appears on an ingredient list. Chemically it is Argireline with two extra residues on the C-terminal end. Argireline is Ac-Glu-Glu-Met-Gln-Arg-Arg-NH₂; this molecule is Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH₂. The name itself carries the design intent — SNAP-25 is the synaptic protein whose N-terminal domain both sequences were patterned after, and inhibiting the assembly of the SNARE complex that protein belongs to is the mechanism the family was built around.

The extension is usually presented as an improvement. It is worth noting what it definitely does: it makes the molecule bigger. At roughly 1,075 g/mol against roughly 889 for the hexapeptide, and with an added aspartate increasing the net charge, it moves further away from the physical profile a molecule needs to cross intact stratum corneum — and poor skin permeability is the single most consistently reported problem for this entire class of ingredient. Whether the added residues buy anything that offsets that is exactly the question the literature does not answer.

Reference data

All figures below are from the public chemical record and were checked against the deposited structure. Unlike the PubChem entry for Argireline, this record’s structure matches the stated sequence, so its formula and mass can be used directly.

The evidence, stated plainly

We searched PubMed for the INCI name, the trade name and the sequence. The result is worth stating precisely, because “limited evidence” is a phrase that gets used to mean anything from “one small trial” to what is actually the case here.

• Standalone studies of Acetyl Octapeptide-3: none found. No published trial, no in-vitro characterisation, no permeability study, no stability study of this ingredient on its own is present in the indexed literature.
• Two papers mention it, both as one component of a commercial product. Avcil et al. (2020) evaluated hyaluronic-acid microneedle patches loaded with arginine/lysine polypeptide, acetyl octapeptide-3, palmitoyl tripeptide-5, adenosine and seaweed extract; the authors were affiliated with the companies developing the product, and the paper itself concludes only that the ingredients “might possibly” act together. Shin et al. (2024) evaluated a dissolving microneedle patch containing hyaluronic acid, acetyl octapeptide-3 and two other actives, in 24 subjects; the authors were staff of the company that makes the patch.
• No Cosmetic Ingredient Review safety assessment was found for this ingredient, and therefore no independently reviewed maximum use concentration of the kind that exists for Acetyl Hexapeptide-8 (0.005%) or hyaluronic acid (2%).

Neither of the two papers can support a claim about this ingredient, because in both cases the ingredient was one of several in a delivery system specifically designed to bypass the skin barrier. A microneedle patch physically punctures the stratum corneum. That is a reasonable engineering answer to the permeability problem — and it also means the result says nothing about the same peptide in a serum.

What exists instead is supplier documentation. That is not nothing: ingredient houses run real work and their technical files often contain more detail than a journal abstract. But it is not peer-reviewed, it is not independent, and we will not restate a figure from it as though it were a citation.

Formulation, stability and storage

Nothing specific to this ingredient is published, so the honest content of this section is short and its basis is named.

• Water phase. Strongly hydrophilic and polyionic; it belongs in the aqueous phase and dissolves readily there.
• Methionine (general peptide chemistry). The sequence carries one methionine, the residue most prone to oxidation across peptide chemistry generally. This is a class property, not a measurement on this material.
• Proteolysis. Cosmeceutical peptides are substrates for skin proteases; no dermal-stability figure has been published for this one.
• Copper. The related hexapeptide has a measured affinity for copper(II). Whether this octapeptide behaves the same way has not, as far as we can find, been measured — so treat a combination with a copper-peptide ingredient as an unknown rather than as safe by analogy.

As raw material it is a lyophilised powder and is stored like one: dry, cold, dark, and not repeatedly cycled to room temperature. How to store peptides covers the general logic.

Verifying identity and purity

Because the published record is thin, the analytical record matters more, not less. Mass spectrometry confirms the material is the labelled molecule by comparing the measured mass against approximately 1,075 Da; HPLC reports how much of the material is that molecule. A vendor selling an ingredient with no independent literature behind it should at minimum be able to prove what is in the vial. See how to read a COA, and check any batch we ship on verify.

Sourcing and related ingredients

Acetyl Octapeptide-3 is supplied as a raw material with a per-batch Certificate of Analysis reporting HPLC purity and mass-spectrometric identity confirmation. It is not supplied as a finished cosmetic, and the certificate is not a cosmetic safety assessment.

The directly comparable ingredient is Acetyl Hexapeptide-8, which has a genuine — if mixed and largely industry-linked — published record, including one independent split-face study that found no significant effect. If you are choosing between the two on evidence, the hexapeptide is the one with evidence to weigh. The full list is on the cosmetic ingredient hub.

Frequently asked questions

Literature cited

1. National Center for Biotechnology Information. “PubChem Compound Summary for CID 76283482, Acetyl octapeptide-3.” pubchem.ncbi.nlm.nih.gov/compound/76283482 (sequence, formula, mass, CAS).
2. Avcil M, Akman G, Klokkers J, Jeong D, Çelik A. “Efficacy of bioactive peptides loaded on hyaluronic acid microneedle patches: A monocentric clinical study.” J Cosmet Dermatol. 2020;19(2):328–337. PMID 31134751. pubmed.ncbi.nlm.nih.gov/31134751. (Five actives; company-affiliated authors.)
3. Shin JY, Han D, Yoon KY, Jeong DH, Park YI. “Clinical Safety and Efficacy Evaluation of a Dissolving Microneedle Patch Having Dual Anti-Wrinkle Effects With Safe and Long-Term Activities.” Ann Dermatol. 2024;36(4):215–224. PMID 39082657. pubmed.ncbi.nlm.nih.gov/39082657. (n = 24; authors employed by the patch manufacturer.)
4. Blanes-Mira C, Merino JM, Valera E, et al. “Small peptides patterned after the N-terminus domain of SNAP25 inhibit SNARE complex assembly and regulated exocytosis.” J Neurochem. 2004;88(1):124–135. PMID 14675156. pubmed.ncbi.nlm.nih.gov/14675156. (Mechanistic background for the SNAP-25-derived peptide family.)
5. Mortazavi SM, Moghimi HR. “Skin permeability, a dismissed necessity for anti-wrinkle peptide performance.” Int J Cosmet Sci. 2022;44(2):232–248. PMID 35302659. pubmed.ncbi.nlm.nih.gov/35302659. (Class-level permeability problem.)