Hexapeptide-9
GPQGPQ, a collagen-motif cosmetic hexapeptide. The one randomized trial on PubMed tested a cyclized version, a different molecule.
Hexapeptide-9 is a synthetic linear hexapeptide, Gly-Pro-Gln-Gly-Pro-Gln, sold as an anti-ageing cosmetic ingredient (PubChem lists it under its INCI name). A 2025 randomized trial compared a cyclized hexapeptide-9 serum with retinol, but cyclization makes a different molecule, so that result does not transfer to the linear ingredient. A 2025 study of an ionic-liquid skin enhancer also applied hexapeptide-9 alone as a comparison arm: in UV-exposed mice it reduced markers of skin damage, and in a small volunteer test its immediate effect on wrinkles was negligible. That paper does not print the sequence. It is not a drug.
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Recommended Dosing
No dosing data yet
This page has no dosing data yet.
Mechanism of action
Not established for the linear peptide. The 2025 trial measured a cyclized analogue designed for greater stability and skin penetration. In UV-exposed mice, hexapeptide-9 applied alone lowered skin malondialdehyde and preserved superoxide dismutase activity and hydroxyproline (2025 study). In UV-exposed mice, hexapeptide-9 applied alone lowered skin malondialdehyde and preserved superoxide dismutase activity and hydroxyproline (2025 study). In UV-exposed mice, hexapeptide-9 applied alone lowered skin malondialdehyde and preserved superoxide dismutase activity and hydroxyproline (2025 study). In UV-exposed mice, hexapeptide-9 applied alone lowered skin malondialdehyde and preserved superoxide dismutase activity and hydroxyproline (2025 study).
Primary uses
- Cosmetic anti-ageing serums and creams
Typical dosing
No controlled study of the ingredient on its own states an amount used on skin, and a supplier's use level is not a source on this site, so none is given.
Regulatory status
Not a drug: listed as a cosmetic ingredient under its INCI name (PubChem CID 16129319). Drugs@FDA and the EMA medicines list hold no record for it (searched October 28, 2026).
Status as of this entry's last review, October 28, 2026. Approvals, compounding rules and sport rules change; the regulatory tracker is checked more often.
What we checked
Hexapeptide-9 is a cosmetic peptide built on a collagen-like Gly-Pro repeat; this section records what can be checked.
Identity, computed
| Sequence | Gly-Pro-Gln-Gly-Pro-Gln (GPQGPQ) |
| Formula | C24H38N8O9 |
| Average mass | 582.62 g/mol |
| Monoisotopic mass | 582.2762 Da |
| Isoelectric point | 6.1 (net charge -0.02 at pH 7) |
The sequence is PubChem's for the INCI ingredient (free acid); the values below are computed and agree with PubChem's formula.
Regulatory status, read October 28, 2026
Drugs@FDA: 0 records for “hexapeptide-9”. EMA medicines list: 0 records for “hexapeptide-9”. Run for semaglutide, the same queries return 6 and 5 records (and the registry search 80 trials), so a zero here is an absence, not a broken search. Not named on the WADA 2026 and 2027 Prohibited Lists. As a substance with no current approval for human therapeutic use, it falls under section S0 (non-approved substances), which is prohibited at all times; the lists were read on October 28, 2026.
What the studies show
A 2025 randomized, double-blinded trial compared a serum of cyclized hexapeptide-9 with a retinol serum and a vehicle over 56 days in volunteers with ageing skin (J Cosmet Dermatol, 2025). The cyclized peptide is a different molecule from the linear ingredient this entry covers, so it is listed in References rather than read as evidence for this one.
A 2025 study made an ionic liquid from GABA and lactic acid to carry hexapeptide-9 into skin and used the peptide alone as a comparison arm. In UV-exposed mice it lowered skin malondialdehyde and preserved superoxide dismutase activity and hydroxyproline, though less than the combined system; in a small volunteer test of immediate effects, skin treated with the peptide alone was much as before apart from higher elasticity at one hour (Wang et al., 2025). The paper does not print the peptide's sequence.
What we looked for and did not find
No controlled trial of the peptide on its own in people, no registry record and no drug approval.
| Source | Query | Results, October 28, 2026 | What it was |
|---|---|---|---|
| PubMed | ("hexapeptide-9"[tiab] OR "hexapeptide 9"[tiab]) | 3 | the hyphenated INCI name is matched word by word (Q958): a phrase search for a hyphen-numbered name misses papers; one record concerns caffeoyl hexapeptide-9, a different molecule, and is not cited |
| ClinicalTrials.gov | hexapeptide-9 | 0 | |
| Drugs@FDA (openFDA) | hexapeptide-9 | 0 | |
| EMA medicines list | hexapeptide-9 | 0 |
References
- [other] PubChem CID 16129319, Hexapeptide-9: formula C24H38N8O9, molecular weight 582.6. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/16129319
- [clinical-trial] Chang H, et al. "Novel Cyclized Hexapeptide-9 Outperforms Retinol Against Skin Aging: A Randomized, Double-Blinded, Active- and Vehicle-Controlled Clinical Trial." J Cosmet Dermatol, 2025;24(7):e70290. PMID: 40586182.
- [pubmed] Wang M, et al. "Pioneering ionic liquids in neuro-soothing: Enhanced transdermal delivery of collagen peptides and their synergistic anti-aging functions." Mater Today Bio, 2025;31:101527. PMID: 39968525.
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This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.