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Evidence: LowPeptide Research Only Cosmetic & Skin

Acetyl Tetrapeptide-3

also known as: Ac-KGHK-NH2, Folixyl

Ac-KGHK-NH2, a cosmetic tetrapeptide used in hair-loss lotions. Its only human trial tested it inside a three-ingredient herbal blend, so its own effect on hair is untested.

Acetyl tetrapeptide-3 is a synthetic tetrapeptide amide, Ac-Lys-Gly-His-Lys-NH2, sold as a cosmetic ingredient for scalp and hair products (PubChem lists it under its INCI name). The one randomized human trial found on PubMed gave it combined with biochanin A and ginseng extracts against 3% minoxidil in androgenetic alopecia, so the result belongs to the combination. It is not a drug and has no drug approval anywhere.

No dosing data yet Details ↓

Dosing

Recommended Dosing

No dosing data yet

This page has no dosing data yet.

Mechanism of action

Not established in published studies. The tetrapeptide is marketed for hair products; the only clinical paper found tested a lotion that also contained biochanin A and ginseng extracts, so no mechanism can be attributed to the peptide itself from human data.

Primary uses

Cosmetic scalp and hair-care formulations
Studied in people only as part of a three-ingredient herbal blend (androgenetic alopecia)

Typical dosing

Not established for human use

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 11752568). 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

Acetyl tetrapeptide-3 is a cosmetic hair-care peptide. Its literature is one combination trial; this section records what can be checked.

Identity, computed

Sequence	Ac-Lys-Gly-His-Lys-NH2 (Ac-KGHK-NH2)
Formula	C22H39N9O5
Average mass	509.61 g/mol
Monoisotopic mass	509.3074 Da
Isoelectric point	none between pH 0 and 14: no acidic group, so the peptide stays positive (net charge +2.24 at pH 7)

The sequence is the one PubChem gives for the INCI ingredient (Ac-Lys-Gly-His-Lys-NH2); the values below are computed for the C-terminal amide and agree with PubChem's formula.

Regulatory status, read October 28, 2026

Drugs@FDA: 0 records for “acetyl tetrapeptide-3”. EMA medicines list: 0 records for “acetyl tetrapeptide-3”. 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 maker or sellers claim

Claim, from cosmetic ingredient marketing: the peptide supports hair growth or reduces hair loss. The one human trial found tested it only mixed with biochanin A and ginseng extracts, so the claim is untested for the peptide alone.

What the studies show

A 24-week randomized trial in 32 adults with androgenetic alopecia compared a lotion of biochanin A, acetyl tetrapeptide-3 and ginseng extracts with 3% minoxidil (Lueangarun and Panchaprateep, 2020). It tested the three-ingredient combination, so it says nothing about the peptide on its own.

What we looked for and did not find

No study of the peptide alone in people, no registry record and no drug approval.

Source	Query	Results, October 28, 2026	What it was
PubMed	("tetrapeptide-3"[tiab] OR "tetrapeptide 3"[tiab]) AND acetyl[tiab]	2	the hyphenated INCI name is matched word by word (Q958): a phrase search for a hyphen-numbered name misses papers; one of the two records is a skin-permeation study of a different peptide, tetrapeptide-3 (Gly-Gln-Pro-Arg), not cited
ClinicalTrials.gov	acetyl tetrapeptide-3	0
Drugs@FDA (openFDA)	acetyl tetrapeptide-3	0
EMA medicines list	acetyl tetrapeptide-3	0

References

[other] PubChem CID 11752568, Acetyl tetrapeptide-3: formula C22H39N9O5, molecular weight 509.6. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/11752568
[clinical-trial] Lueangarun S, et al. "An Herbal Extract Combination (Biochanin A, Acetyl tetrapeptide-3, and Ginseng Extracts) versus 3% Minoxidil Solution for the Treatment of Androgenetic Alopecia: A 24-week, Prospective, Randomized, Triple-blind, Controlled Trial." J Clin Aesthet Dermatol, 2020;13(10):32-37. PMID: 33584955.

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Acetyl Tetrapeptide-2

A firming cosmetic peptide sold as Uplevity, sequence undisclosed. Its supplier's claims are unpublished; one hair-lotion trial used it among several actives.

GHK-Cu

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Palmitoyl Tetrapeptide-7

Pal-GQPR, the second peptide in a popular anti-wrinkle blend: studied alone only in a 2026 cell screen and a three-person skin permeation study; its IL-6 claim has no published source.

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Disclaimer

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.