Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library

Palmitoyl tripeptide-38 (Matrixyl synthe'6): what the evidence says

Name: Palmitoyl tripeptide-38 (Matrixyl synthe'6)
Published: 2026-10-27

At a glance

What it is: a three-amino-acid peptide (lysine-oxidized methionine-lysine) with a fatty palmitoyl tail, sold under the trade name Matrixyl synthe'6. It is a different molecule from Matrixyl (palmitoyl pentapeptide-4) and Matrixyl 3000. ^R1

What the evidence says: 🟨 the only human study found was open-label (no control group): women using a serum that also contained vitamins C and E had smoother skin after 56 days. Because of the other ingredients, the effect cannot be credited to this peptide. ^R2

Biggest risks: no specific safety signals reported, but published human safety data are minimal.

Rating


Human Human evidence	Very limited: one open-label multi-ingredient study ^R2
Animal Animal / lab evidence	Not reviewed
Regulatory	Cosmetic ingredient; not FDA-approved ^R3 · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page ^{R4, R5, R6} · not named by WADA ^R7
Established human dose	No

Evidence verdict: Wrinkles and skin texture: Very limited (one open-label study of a multi-ingredient serum)

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: no placebo, no control group, and several active ingredients at once; results were partly self-assessed.

What is it?

Related pages: matrixyl, matrixyl-3000, ghk-cu.

Does it work?

🟨 Multi-ingredient serum (open-label, 56 days): skin roughness down 8% to 9%; redness and evenness improved. Vitamin C and E in the same serum make it impossible to isolate the peptide's effect. ^R2
⚪ Peptide alone: no human data found.

Is it safe?

No safety problems reported in the open-label study. ^R2
Patch-test new products.

Gray-market vials: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.

Is it legal?

US: sold as a cosmetic ingredient. Cosmetics do not need FDA approval before sale; products making drug-type claims can be regulated as drugs. ^R3 No Drugs@FDA application found (openFDA searched Oct 27, 2026).
Compounding: not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R4, R5, R6}
Sport: not named on WADA's 2026 Prohibited List. ^R7

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
Lintner 2020 (open-label)	Women 40+ with photoaging	Topical serum with vitamins C and E	5 ppm in serum	56 days	Roughness −8% to −9%; redness −9%	PMID 33103342

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 27, 2026)

^R1 PubChem CID 71587932, Palmitoyl tripeptide-38 (synonyms include Matrixyl Synthe'6; Pal-Lys-Met(O2)-Lys), checked Oct 27, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/71587932
^R2 Lintner K, et al. J Cosmet Dermatol. 2020. PMID 33103342
^R3 FDA. Is It a Cosmetic, a Drug, or Both? (Or Is It Soap?) Content current as of Sep 11, 2024. https://www.fda.gov/cosmetics/cosmetics-laws-regulations/it-cosmetic-drug-or-both-or-it-soap
^R4 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R5 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R6 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R7 WADA. The 2026 Prohibited List, full list checked; compound not named. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Palmitoyl tripeptide-38 (Matrixyl synthe'6). This is a cosmetic ingredient, not an FDA-approved drug. Cosmetic products are not reviewed by FDA for effectiveness before sale. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).