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Part of the skin and hair peptide hub: every topical and cosmetic peptide we cover, with its evidence grade.

Evidence: LowPeptide Research Only Cosmetic & Skin

Palmitoyl Tripeptide-28

also known as: Pal-Arg-Phe-Lys, Pal-RFK

Pal-RFK, a palmitoylated tripeptide sold for skin-care products. PubMed holds no study of it.

Palmitoyl tripeptide-28 is a synthetic lipopeptide, a palmitoyl group on the tripeptide Arg-Phe-Lys (PubChem's record, under its INCI name). It is sold as a skin-care ingredient, but a title-and-abstract search of PubMed for its INCI name finds no study of it. It is not a drug.

No dosing data yet Details ↓

Mechanism of action

Not established: no published study describes its action.

Primary uses

Typical dosing

Not established for human use

No published study states an amount of this ingredient 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: PubChem lists it under its INCI name as a cosmetic ingredient (CID 171390254). 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

Palmitoyl Tripeptide-28 is a cosmetic peptide ingredient with little or no published literature; this section records what can be checked.

Identity, computed

Structurepalmitoyl-Arg-Phe-Lys, free acid (PubChem's synonym and IUPAC name, CID 171390254)
FormulaC37H65N7O5 (PubChem)
Molecular weight688.0 g/mol (PubChem)

The calculator used elsewhere on this site does not handle this N-terminal acyl group, so the formula and weight are PubChem's, not computed here.

Regulatory status, read October 29, 2026

Drugs@FDA: 0 records for “palmitoyl tripeptide-28”. EMA medicines list: 0 records for “palmitoyl tripeptide-28”. Run for semaglutide, the same queries return 6 and 5 records (and the registry search 81 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 we looked for and did not find

No published study of any kind, no registry record and no drug approval.

SourceQueryResults, October 29, 2026What it was
PubMed("tripeptide-28"[tiab] AND palmitoyl[tiab])0name matched word by word in title/abstract (a phrase search misses hyphen-numbered names)
ClinicalTrials.govpalmitoyl tripeptide-280
Drugs@FDA (openFDA)palmitoyl tripeptide-280
EMA medicines listpalmitoyl tripeptide-280

References

  1. [other] PubChem CID 171390254, Palmitoyl Tripeptide-28: formula C37H65N7O5, molecular weight 688.0. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/171390254

Related peptides

Palmitoyl Tripeptide-5

Syn-Coll (Pal-KVK), a palmitoyl tripeptide sold as a collagen booster on the maker's claim that it copies thrombospondin-1's TGF-beta-activating motif. Its published tests are formulation work and multi-ingredient products.

Palmitoyl Tripeptide-38

Matrixyl Synthe'6, a palmitoyl tripeptide sold with the maker's claim that it rebuilds six skin-matrix components. Every published test used it inside a multi-ingredient product, so its own effect has not been measured.

Pal-GHK

The palmitoylated form of the GHK tripeptide (distinct from GHK-Cu) — widely used as a cosmetic ingredient in combination with Matrixyl (Matrixyl 3000 is Pal-GHK + Pal-KTTKS) for fine-line reduction.

Palmitoyl Pentapeptide-4

The palmitoylated procollagen fragment sold as Matrixyl (pal-KTTKS): in a 12-week split-face trial in 93 women a moisturiser containing it reduced wrinkles more than the same moisturiser alone. A cosmetic ingredient, not a drug.

Guides & tools

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.