Reviewed & approved by Dr. Nova Reyes · Last checked 2026-10-26. ← Back to Evidence Library

Matrixyl (palmitoyl pentapeptide-4): what the evidence says

Name: Matrixyl (palmitoyl pentapeptide-4)
Creator: Dr. Nova Reyes
Published: 2026-10-26

At a glance

What it is: a 5-amino-acid peptide (Lys-Thr-Thr-Lys-Ser, "KTTKS") from type I procollagen, with a fatty palmitoyl tail added so it sits in skin. It is a common anti-wrinkle cosmetic ingredient, sold as Matrixyl. Its official cosmetic name is palmitoyl pentapeptide-4 (older name: palmitoyl pentapeptide-3). ^{R1, R2} UNVERIFIED INCI naming history.

What the evidence says: in a 93-woman, placebo-controlled split-face study, a moisturizer with Pal-KTTKS reduced wrinkles and fine lines more than the plain moisturizer over 3 months. ^R1 Lab studies show it raises collagen in skin cells. ^R2

Biggest risks: well tolerated on skin in the trial. Not tested as an injection.

Rating


Human Human evidence	Limited for wrinkles as a cream (one moderate-size controlled trial, industry-run) ^R1 · Very limited for eye-area products with peptide blends ^R3 · None for injection
Animal Animal / lab evidence	Collagen production in fibroblasts; rat wound studies ^{R2, R4, R5}
Regulatory	Cosmetic ingredient, not an approved drug · Not on FDA 503A or 503B bulk lists ^{R6, R7}
Established human dose	None as a drug. Study details lists what studies used

Evidence verdict: Fine lines and wrinkles as a cosmetic cream: Limited (one 93-person controlled trial plus small industry studies) · Injection or any internal use: No human data Card verdict: Limited (wrinkles, topical cosmetic cream) · Injection or internal use: No human data Card note: Cosmetic cream ingredient; never tested by injection. Varies by use, see page.

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: the main human trial was run by Procter & Gamble scientists. Most other human data are cosmetic-company split-face studies of blends. ^{R1, R3} UNVERIFIED sponsor affiliation inferred from author list, not from a funding statement.

What is it?

Short collagen fragments like KTTKS may signal skin cells to make more collagen. Some "Matrixyl 3000" products combine palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7; this page covers Pal-KTTKS. Related pages: GHK-Cu, SNAP-8, AHK-Cu.

Does it work?

Human Robinson 2005: 93 women aged 35–55, 3 months, randomized split face. The peptide side had fewer wrinkles and fine lines by image analysis and expert grading; women also reported improvement. ^R1
Human Eye-area study (2009): two small split-face studies of products with peptide blends; we cannot separate the effect of Pal-KTTKS. ^R3
Animal Lab: raised collagen in human dermal and corneal fibroblasts. Microneedles increased skin penetration of short peptides in human skin samples. ^{R2, R8}
Animal Wounds: rat studies of Matrixyl patches and creams. ^R5

Is it safe?

Human Well tolerated on skin in the 93-person trial. ^R1
Animal In lab scar models it raised pro-scarring signals (CTGF, α-SMA) in fibroblasts; the meaning for skin is unclear. ^R4
Unknown No data for injection or internal use.

Gray-market "research use only" Matrixyl: 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. Injecting or microneedling a cosmetic-grade powder adds infection and reaction risk that cosmetic testing does not cover.

What we don't know

Unknown Whether results last after stopping
Unknown How it compares with retinoids or sunscreen
Unknown Independent (non-industry) trials

Is it legal?

US: sold legally as a cosmetic ingredient. It is not an approved drug, and it is not on the 503A or 503B bulk lists, so there is no compounding route for injection. ^{R6, R7}
Athletes: not named on the WADA 2026 list.

Study details

These are amounts researchers used, not recommendations. | Study | People / model | Route | Amount used | Follow-up | Reported | Citation | |---|---|---|---|---|---|---| | Robinson 2005 | 93 women aged 35–55 | Cream on half of face | 3 ppm Pal-KTTKS in moisturizer, twice a day Caution frequency | 12 weeks | Fewer wrinkles vs placebo side | [PMID 18492182](https://pubmed.ncbi.nlm.nih.gov/18492182/) | | Jones 2013 | Human fibroblasts (lab) | Culture | Concentrations near aggregation point | Days | More collagen | [PMID 23320752](https://pubmed.ncbi.nlm.nih.gov/23320752/) |

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Robinson LR, et al. Int J Cosmet Sci. 2005. PMID 18492182
^R2 Jones RR, et al. Mol Pharm. 2013. PMID 23320752
^R3 Kaczvinsky JR, et al. J Cosmet Dermatol. 2009. PMID 19735523
^R4 Park H, et al. Tissue Eng Regen Med. 2017. PMID 30603464
^R5 Kachooeian M, et al. ACS Omega. 2022. PMID 35874243
^R6 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R7 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R8 Mohammed YH, et al. PLoS One. 2014. PMID 25033398

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Matrixyl (palmitoyl pentapeptide-4). Talk to a dermatologist you trust, especially if you have sensitive or broken skin or plan to inject or microneedle any product. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).