Matrixyl Research

Matrixyl is a trademark rather than a compound name, which changes how its research literature has to be read. The name belongs to Sederma, the French ingredient supplier now part of Croda, and the molecule marketed under it is palmitoyl pentapeptide-4, written Pal-KTTKS. Almost every human study of it was produced or funded by a company selling cosmetic products containing it. Every human anti-wrinkle endpoint in the record is an instrument reading, an expert grading or a subject questionnaire.

What Matrixyl is, and what the name covers

Palmitoyl pentapeptide-4 is a lipidated pentapeptide, not a protein and not a peptide hormone. Its peptide portion is lysine-threonine-threonine-lysine-serine, with a palmitic acid chain at the amino terminus. PubChem records the free base as CID 9897237 under CAS 214047-00-4, formula C39H75N7O10, molecular weight 802.1. Retail material is frequently an acetate or trifluoroacetate salt, so a certificate showing a different weight is not automatically an error.

Three naming points cause repeated confusion.

• Palmitoyl pentapeptide-3 is the former INCI name for this same molecule, and PubChem carries both names against one record.
• The INCI name covers two sequences. The 2024 CIR safety assessment lists two CAS numbers jointly against that single INCI name, 214047-00-4 and 521091-64-5.^[17] On PubChem, 214047-00-4 resolves to the Pal-KTTKS structure and 521091-64-5 to Pal-KTSKS. An INCI declaration alone does not identify which sequence is present.
• Matrixyl 3000 and Matrixyl synthe'6 are separate Sederma blends built on other palmitoylated peptides, and neither is a source of evidence about Pal-KTTKS.

Research-grade Matrixyl corresponds to the Pal-KTTKS sequence.

How Pal-KTTKS is proposed to work

The mechanism originates in cell culture and predates any cosmetic application. Working in vitro in mesenchymal cells in 1993, Katayama and colleagues dissected the C-terminal propeptide of type I procollagen. They identified KTTKS as the minimum sequence stimulating type I collagen, type III collagen and fibronectin production.^[1] That experiment used the free, unpalmitoylated peptide.

Jones and colleagues at the University of Reading later reported that C16-KTTKS stimulated collagen production in cultured human dermal and corneal fibroblasts in vitro.^[2] That work carries no manufacturer affiliation, and the response clustered near the molecule's critical aggregation concentration, pointing toward self-assembly rather than a clean receptor-mediated signal.

No published study has quantified collagen histologically in living human skin after topical application of this peptide.

The permeation problem

Delivery is the weakest link in the mechanistic chain. In an in vitro Franz cell study on full-thickness hairless mouse skin, neither KTTKS nor Pal-KTTKS permeated the skin.^[3] Free KTTKS was not detected in any skin layer at all. Pal-KTTKS reached the skin layers, but only a minor fraction of the applied dose stayed anywhere in skin. A much smaller fraction reached the dermis, where the fibroblasts underpinning the mechanism sit. Both peptides broke down rapidly in skin extracts, and the 2024 CIR assessment reproduces these permeation findings.^[17]

Two independent reviews bear on that gap. Abu Samah and Heard at Cardiff University described a sound in vitro basis for a fibroblast effect, alongside a surprising absence of in vitro skin penetration data.^[4] Mortazavi and Moghimi concluded that the permeability of anti-wrinkle peptides including KTTKS can be raised by enhancement approaches.^[5] That is a review's appraisal of methods, not a demonstration of benefit in a trial.

Matrixyl research in humans

One trial isolates this peptide as the single variable. Robinson and colleagues compared a moisturizer against the same moisturizer containing Pal-KTTKS, in a 12-week, double-blind, placebo-controlled, split-face study in 93 women.^[6] The peptide product produced significant improvement versus placebo for wrinkle and fine line reduction, measured by quantitative image analysis and by expert grader analysis. Every author was affiliated with The Procter & Gamble Company, and the endpoints were instrumental imaging, expert grading and self-report, with no biopsy and no histology. The abstract reports no effect sizes, and no independent group has replicated the result in the twenty-one years since.

The one wrinkle trial of this peptide run outside a large multinational's own laboratories was null. Aruan and colleagues compared an acetylhexapeptide-3 cream, a palmitoyl pentapeptide-4 cream and placebo in Indonesian women with crow's feet.^[7] Groups held seven subjects each and ran eight weeks. In the full text, no endpoint reached statistical significance on corneometry, transepidermal water loss, cutometry, the Crow's Feet Grading Scale or self-assessment. The abstract nonetheless states that the pentapeptide showed better results than the comparator and placebo, which the paper's own statistics do not support. An Indonesian cosmetics manufacturer funded the study, and the authors cite sample size and duration as limitations.

Two more human studies from Procter & Gamble tested multi-ingredient products, and neither can isolate the peptide. Kaczvinsky and colleagues measured periorbital roughness over four weeks in two split-face studies of products containing niacinamide, carnosine and two peptides including Pal-KTTKS.^[8] Results were mixed within each study, and only the authors' pooled analysis made all three products significantly better on both roughness parameters. The comparator was no treatment rather than a vehicle. Fu and colleagues reported that a cosmetic regimen improved wrinkle appearance more than prescription tretinoin in 196 women.^[9] CIR identifies that regimen's test article as containing palmitoyl pentapeptide-4 alongside niacinamide and retinyl propionate.^[17]

The only fully independent randomized trial in humans of a Matrixyl-containing product is negative. Röper and colleagues at TU Munich tested a cream containing Matrixyl against a dexpanthenol lotion in 20 breast cancer patients.^[10] The indication was prophylaxis of acute radiation dermatitis, and no advantage was found on any toxicity score. It is also the sole location of a human harm signal in this literature. Mild itchiness and sporadic efflorescences were more frequent in the Matrixyl arm, and adverse events occurred exclusively in that arm. One suspected allergic reaction was recorded, and two patients required re-simulation because their skin marks had degraded. The authors concluded that higher costs and problems with skin marks prevent a general recommendation. The product was multi-ingredient, and the indication is not wrinkles.

Independent animal work in wound models is positive. Kachooeian and colleagues randomized rats across seven arms in a 21-day wound model and reported improved wound healing.^[11] Rasouli and colleagues randomized rats across four groups in a burn model, and a cellulose dressing carrying Pal-KTTKS healed better than the same dressing without it.^[18] Neither author group carries a manufacturer affiliation. Both are rat wound healing, not human anti-wrinkle efficacy.

An independent systematic review of clinical designs for matrix-stimulating cosmetic peptides found 15 studies across 12 papers.^[12] Of those 15 human studies, only six used a placebo control and only five were double-blind. Its authors concluded that the literature is sparse and that most experiments were neither double-blind nor placebo-controlled. They called for better planned and controlled clinical trials in this area. A 2026 meta-analysis of 19 randomized peptide trials found a modest pooled wrinkle effect, largely driven by oral polypeptides.^[13] No included trial in it tested palmitoyl pentapeptide-4. Its intervention definition does name Matrixyl, but only as an example of a topical signal peptide.

Sponsorship in the literature

Sponsorship is close to total here. Procter & Gamble authorship covers the pivotal trial and two multi-ingredient product studies.^[6][8][9] Sederma holds the trademark, supplied much of the unpublished toxicology CIR reviewed, and is the address on the two foundational articles.^[14][15] Karl Lintner, author of those articles, remains a co-author on a 2026 peptide safety paper whose other authors are at Procter & Gamble.^[16] The null trial's investigators declared no conflicts while disclosing manufacturer funding.^[7] CIR is funded by the Personal Care Products Council, the US cosmetics trade association.

Röper 2004 is the only human study in the record with no commercial sponsor, and it was negative.^[10] No unconflicted human study in the record supports an effect. The unconflicted supportive results are in vitro experiments and animal wound-healing work.^{[1][2][11][18]}

Route, safety review and regulatory status

No published route other than topical has evidence behind it. A PubMed search for KTTKS combined with oral, injection, subcutaneous or intravenous terms returns no records. The same search combined with pharmacokinetics returns none. ClinicalTrials.gov returns no registered studies under KTTKS, palmitoyl pentapeptide or Matrixyl. One unpublished 1999 acute oral screen in rats was submitted to CIR, and it is the only non-topical exposure datum in the record.^[17]

There is no drug approval for palmitoyl pentapeptide-4 anywhere, for any indication or route, and its regulatory footing is cosmetic. The CIR Expert Panel concluded in November 2024 that the ingredient is safe in cosmetics at the practices of use and concentration described in its assessment.^[17] Four qualifications belong with that conclusion. CIR is an industry-funded expert panel rather than a regulator, and it addressed safety rather than efficacy. The Panel stated that no subchronic, chronic, developmental, reproductive or carcinogenicity studies were found or submitted. It separately found the data insufficient to support safe use of cosmetic ingredients applied via an airbrush delivery system. The declared use concentrations underpinning the conclusion are parts-per-million level, as is the concentration used in the pivotal trial.

No case report or safety series on palmitoyl pentapeptide-4 has been published. A PubMed search combining the compound with allergic contact dermatitis, sensitization and adverse terms returns six records, none of which is a case report or a safety series. That is an absence of adverse-event data rather than a demonstration of safety. The only human harm signal in the record sits in the radiation dermatitis trial.^[10]

Much of the newer supplier toxicology in the CIR package was run on the Pal-KTSKS sequence rather than on Pal-KTTKS. CIR names the tested sequence in many of those study summaries, so the two can be told apart there.^[17]

Two endocrine assays in that package disagree, and both were run on a formulation CIR labels Pal-KTSKS. A 2020 XenoScreen YES/YAS assay reported estrogenic agonist activity in vitro.^[17] Its estrogen antagonist and both androgen arms were negative. That same in vitro assay observed cellular toxicity at its two highest test concentrations in the androgen screen.^[17] A 2021 XenoScreen XL YES assay on the same formulation found no estrogenic agonist activity. The Panel rests its waiver of the missing reproductive and carcinogenicity data on the negative assay.

The ocular irritation results in that package are mixed and depend on the formulation tested.^[17] An in vitro hen's egg chorioallantoic membrane assay on trade name material of the Pal-KTTKS sequence was classified as moderately irritating. The same assay type on a more concentrated Pal-KTSKS formulation was classified only as slightly irritating. A reconstructed human corneal model in vitro found the Pal-KTSKS formulation not irritating. In an animal test, rabbit eyes were unirritated by the Pal-KTTKS material. The one moderately irritating result in the set came from Pal-KTTKS material, the sequence sold under the Matrixyl name.

The Panel also noted changes in the keratin profile of subjects treated with a facial cream containing the ingredient, suggesting a potential biologic effect.^[17] It judged these non-adverse rather than beneficial, citing the absence of erythema, dryness and transepidermal water loss.

Conclusion

Palmitoyl pentapeptide-4 has a coherent in vitro rationale and a thin, heavily sponsored human record. The collagen mechanism was established in cell culture for the free peptide, and permeation work indicates the palmitoylated form largely stays out of the dermis. The one manufacturer trial that isolates the peptide is positive and unreplicated, one industry-funded independent trial is null, and the one unsponsored human trial is negative. Reading this literature accurately depends on separating the trademark, the INCI name and the sequence actually tested.

Palmitoyl pentapeptide-4 is a research compound, supplied for laboratory research use only.

Frequently Asked Questions

Is Matrixyl the name of a peptide? No. Matrixyl is a trade name belonging to Sederma, the French ingredient supplier now part of Croda. The peptide marketed under that name is palmitoyl pentapeptide-4, written Pal-KTTKS, and its two foundational articles were authored from the Sederma address.^[14][15]

Has palmitoyl pentapeptide-4 been tested in humans? Yes, in a small number of studies, and the results do not agree. One manufacturer-run trial in 93 women isolated the peptide and reported significant improvement versus placebo on imaging and grader endpoints.^[6] It has not been replicated independently in twenty-one years. An industry-funded trial with seven subjects per arm found no endpoint reaching statistical significance, and the only human study with no commercial sponsor was negative.^[7][10]

Do Matrixyl 3000 and Matrixyl synthe'6 contain the same peptide? No. They are separate Sederma blends built on other palmitoylated peptides, and neither is a source of evidence about Pal-KTTKS.

Is there evidence for any route other than topical application? No published route other than topical has evidence behind it. A PubMed search for KTTKS combined with oral, injection, subcutaneous or intravenous terms returns no records, and the same search combined with pharmacokinetics returns none. ClinicalTrials.gov returns no registered studies under KTTKS, palmitoyl pentapeptide or Matrixyl.

References

1. 1

   Katayama K, Armendariz-Borunda J, Raghow R, Kang AH, Seyer JM. A pentapeptide from type I procollagen promotes extracellular matrix production. J Biol Chem. 1993;268(14):9941-9944. PMID 8486721.
2. 2

   Jones RR, Castelletto V, Connon CJ, Hamley IW. Collagen stimulating effect of peptide amphiphile C16-KTTKS on human fibroblasts. Mol Pharm. 2013;10(3):1063-1069. PMID 23320752.
3. 3

   Choi YL, Park EJ, Kim E, Na DH, Shin YH. Dermal stability and in vitro skin permeation of collagen pentapeptides (KTTKS and palmitoyl-KTTKS). Biomol Ther (Seoul). 2014;22(4):321-327. PMID 25143811.
4. 4

   Abu Samah NH, Heard CM. Topically applied KTTKS: a review. Int J Cosmet Sci. 2011;33(6):483-490. PMID 21535443.
5. 5

   Mortazavi SM, Moghimi HR. Skin permeability, a dismissed necessity for anti-wrinkle peptide performance. Int J Cosmet Sci. 2022;44(2):232-248. PMID 35302659.
6. 6

   Robinson LR, Fitzgerald NC, Doughty DG, Dawes NC, Berge CA, Bissett DL. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-160. PMID 18492182.
7. 7

   Aruan RR, Hutabarat H, Widodo AA, Firdiyono MTCC, Wirawanty C, Fransiska L. Double-blind, randomized trial on the effectiveness of acetylhexapeptide-3 cream and palmitoyl pentapeptide-4 cream for crow's feet. J Clin Aesthet Dermatol. 2023;16(2):37-43. PMID 36909866. Full text: PMC10005804.
8. 8

   Kaczvinsky JR, Griffiths CE, Schnicker MS, Li J. Efficacy of anti-aging products for periorbital wrinkles as measured by 3-D imaging. J Cosmet Dermatol. 2009;8(3):228-233. PMID 19735523.
9. 9

   Fu JJ, Hillebrand GG, Raleigh P, Li J, Marmor MJ, Bertucci V, et al. A randomized, controlled comparative study of the wrinkle reduction benefits of a cosmetic niacinamide/peptide/retinyl propionate product regimen vs. a prescription 0.02% tretinoin product regimen. Br J Dermatol. 2010;162(3):647-654. PMID 20374604.
10. 10

    Röper B, Kaisig D, Auer F, Mergen E, Molls M. Thêta-Cream versus Bepanthol lotion in breast cancer patients under radiotherapy. A new prophylactic agent in skin care? Strahlenther Onkol. 2004;180(5):315-322. PMID 15127162.
11. 11

    Kachooeian M, Mousivand Z, Sharifikolouei E, Shirangi M, Firoozpour L, Raoufi M, Sharifzadeh M. Matrixyl patch vs Matrixyl cream: a comparative in vivo investigation of Matrixyl (MTI) effect on wound healing. ACS Omega. 2022;7(28):24695-24704. PMID 35874243.
12. 12

    Michalek IM, Lelen-Kaminska K, Caetano Dos Santos FL. Peptides stimulating synthesis of extracellular matrix used in anti-ageing cosmetics: are they clinically tested? A systematic review of the literature. Australas J Dermatol. 2019;60(4):e267-e271. PMID 30941744.
13. 13

    Nukaly HY, Halawani IR, Irtaza HM, et al. Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials. Front Med (Lausanne). 2026;13:1618306. PMID 41924746.
14. 14

    Lintner K, Peschard O. Biologically active peptides: from a laboratory bench curiosity to a functional skin care product. Int J Cosmet Sci. 2000;22(3):207-218. PMID 18503476.
15. 15

    Lintner K. Promoting production in the extracellular matrix without compromising barrier. Cutis. 2002;70(6 Suppl):13-16. PMID 12498533.
16. 16

    Bjerke DL, Li J, Gao Y, et al. A framework for the safety evaluation of peptides in cosmetics. Curr Res Toxicol. 2026;10:100291. PMID 41953401.
17. 17

    Cosmetic Ingredient Review Expert Panel for Cosmetic Ingredient Safety. Safety assessment of myristoyl pentapeptide-4, palmitoyl pentapeptide-4, and pentapeptide-4 as used in cosmetics. Final Report, release date 18 November 2024; panel meeting 30 September to 1 October 2024. FR_Pentapeptides_092024.pdf, 21 pages. No PubMed ID; not indexed in PubMed.
18. 18

    Rasouli M, Shahghasempour L, Shirbaghaee Z, Hosseinzadeh S, Abbaszadeh HA, Fattahi R, Ranjbari J, Soleimani M. Mesenchymal stem cell therapy using Pal-KTTKS-enriched carboxylated cellulose improves burn wound in rat model. Arch Dermatol Res. 2024;316(7):353. PMID 38850353.