Matrixyl: what palmitoyl pentapeptide-4 is, what the trials found and what is unknown

Matrixyl is a brand name owned by the French ingredient company Sederma for palmitoyl pentapeptide-4, a small synthetic peptide used in anti-wrinkle creams since the early 2000s. The peptide part, KTTKS, is a five-amino-acid sequence copied from the C-terminal propeptide of type I procollagen, the part of the collagen precursor that is cut off as collagen fibres assemble. In 1993 researchers at the University of Tennessee dissected that propeptide and found that KTTKS, residues 212 to 216, was the minimum sequence needed to stimulate collagen and fibronectin production in fibroblasts, the cells that build the skin’s dermal matrix ^[1]. They proposed that fragments released during tissue repair act as a feedback signal telling fibroblasts to make more matrix.

On its own, KTTKS is very water-soluble and does not get through the skin. Sederma’s solution, described in a 2000 paper, was to attach a long-chain fatty acid; the palmitoyl group makes the peptide fat-soluble enough to penetrate the stratum corneum and, the authors reported, improves both its specific activity and its cost-effectiveness ^[2]. The resulting Matrixyl peptide is written Pal-KTTKS or C16-KTTKS, after the 16-carbon palmitic acid. Its cosmetic ingredient name was originally palmitoyl pentapeptide-3 and is now palmitoyl pentapeptide-4; both names refer to the same compound.

The Matrixyl name has since been extended to a family of Sederma products that contain different peptides. Matrixyl 3000 is a blend of palmitoyl tripeptide-1, which is Pal-GHK, and palmitoyl tetrapeptide-7, and does not contain Pal-KTTKS at all. Matrixyl Synthe’6 is palmitoyl tripeptide-38. When a research peptide store lists Matrixyl, it almost always means Pal-KTTKS, but the label is worth checking. This guide covers Pal-KTTKS. Reviews of topical peptides class it as a signal peptide, alongside neurotransmitter-inhibitor peptides such as SNAP-8 and carrier peptides such as GHK-Cu ^[13].

The mechanism is the one Katayama’s group described for KTTKS: the peptide signals fibroblasts to increase production of type I and type III collagen and fibronectin, without changing total protein synthesis or cell number ^[1]. In the cosmetic context that is presented as replacing the collagen that the dermis loses with age and sun exposure, and so plumping fine lines from beneath.

Later cell work supports the collagen effect but adds a twist. A 2013 study found that C16-KTTKS stimulated collagen production by human dermal and corneal fibroblasts in a concentration-dependent way, and that the effect appeared close to the concentration at which the lipopeptide self-assembles into nanotape structures, suggesting that its behaviour as a surfactant-like molecule and its biological activity are linked ^[8]. A 2026 follow-up from the same group confirmed collagen stimulation in human dermal fibroblasts at a concentration of 0.0062% by weight, and found the same for an arginine-substituted variant, with the salt form making no difference ^[9]. Gene-expression profiling by Procter & Gamble researchers, who use Pal-KTTKS in their products, reported that it increases expression of matrix genes such as COL1A1, COL3A1 and elastin in adult fibroblasts, particularly in combination with niacinamide ^{[11] [12]}.

The unanswered question, as with every cosmetic peptide, is delivery. The palmitoyl group helps: a 2014 study on hairless mouse skin found that plain KTTKS was not detected in any skin layer, while Pal-KTTKS was found in the stratum corneum, epidermis and dermis, though neither passed all the way through the skin, and both were degraded rapidly by skin proteases ^[6]. A physicochemical study measured the change directly: KTTKS has a logP of about −1.6, meaning it strongly prefers water, while Pal-KTTKS has a calculated logP of about 3.7, meaning it prefers fat, and it behaves as a surfactant with a critical micelle concentration of about 19 mg/L ^[7]. Whether enough reaches the fibroblasts of the deep dermis to raise collagen production in living skin has not been measured; the human trials below infer it from the clinical result.

The Matrixyl benefits claimed on product labels are fewer and shallower wrinkles, firmer skin, improved texture and, less often, faster wound healing. The peptide has better evidence for the first of these than most cosmetic ingredients, and none for injectable use.

Wrinkles: the key study is a 2005 trial by Procter & Gamble researchers. Ninety-three white women aged 35 to 55 applied a moisturiser containing 3 parts per million of Pal-KTTKS to one side of the face and the same moisturiser without it to the other, twice daily for 12 weeks, in a double-blind, randomised, split-face design. The Pal-KTTKS side showed significantly greater reduction in wrinkles and fine lines than the control side by both computer image analysis and expert grading, and subjects noticed the difference in self-assessments ^[3]. That is a real, placebo-controlled result, but note its scale: 3 ppm is 0.0003%, the comparison was against the same moisturiser, and the endpoints were changes in wrinkle measurements rather than anything visible across a room. Two further split-face studies in 42 and 35 women found that products containing niacinamide, Pal-KT and Pal-KTTKS improved crow’s feet smoothness and wrinkle depth after four weeks compared with no treatment, though the peptide’s own contribution cannot be separated from the niacinamide ^[5].

Matrixyl vs Argireline: a 2023 double-blind trial in 21 Indonesian women compared a palmitoyl pentapeptide-4 cream, an acetyl hexapeptide-3 (Argireline) cream and placebo on crow’s feet for eight weeks; the pentapeptide did better than both the hexapeptide and placebo on instrument readings, photographs and self-assessment, though the authors called it an initial study needing larger numbers ^[4]. Matrixyl vs retinol: there is no head-to-head trial. Retinoids have a much larger clinical literature and work through nuclear receptors that alter gene expression across the epidermis and dermis; Pal-KTTKS is a single signal to fibroblasts. Products often combine them, and the 2009 studies above included a retinyl propionate wrinkle treatment alongside the peptide products ^[5].

Wound healing: in a 2022 rat study, patches and creams containing 1 mg of Matrixyl improved wound closure by up to about 82% relative to untreated controls over 21 days, with better re-epithelialisation for the patch ^[10]. That is an animal study of topical application to open wounds, not evidence for skin repair in people. Related work has made KTTKS derivatives with antibacterial activity, but those are different molecules.

The published human evidence for Matrixyl is: the 93-woman split-face trial at 3 ppm over 12 weeks ^[3]; two split-face studies of multi-ingredient products over four weeks ^[5]; and the 21-woman three-arm trial against Argireline and placebo over eight weeks ^[4]. All were topical, all measured wrinkle parameters, and the largest was run by the company that sells the products. No registered clinical trial of palmitoyl pentapeptide-4 as a drug exists as of September 2026.

That is a thin record for a molecule that has been in creams for 25 years, but it is more than most cosmetic peptides have, and the split-face design, where each face serves as its own control, is a reasonable way to test a small effect. What the trials do not show is any effect on deep wrinkles, sagging or skin thickness, any benefit lasting after use stops, or anything at all about the peptide taken any other way.

The main trial measured at 12 weeks, and it is not clear from the report when differences first appeared ^[3]. The four-week product studies found measurable smoothing at four weeks ^[5], and the Argireline comparison ran for eight weeks ^[4]. So the honest answer to how long Matrixyl takes to work is one to three months of twice-daily application to see the small changes the trials measured. Collagen turnover is slow, and a peptide that acts by asking fibroblasts to make more of it cannot work in days.

Matrixyl dosage is a question about the concentration in a cream, and the published figure is strikingly low: 3 ppm, or 0.0003%, in the 93-woman trial ^[3]. The commercial Matrixyl ingredient is supplied as a dilute solution, and Sederma’s recommended use level for the ingredient is a few percent of the finished product, which works out at a few ppm of the peptide itself, so the trial concentration is representative of what a cream contains. In cell culture, collagen stimulation appears at around 0.006% by weight ^[9].

No published study has given Pal-KTTKS by injection, by mouth or under the skin. There is therefore no injected dose to report, and none of the figures above are recommendations. Research stores sell vials of 10 mg to 200 mg, quantities that would formulate litres of cream at the trial concentration. The peptide calculator will convert vial contents to a solution concentration, which is useful for making a topical solution but has no injected-dose meaning.

Every study of Matrixyl in people applied it in a cream or lotion. It is formulated with the fatty chain in mind: Pal-KTTKS inserts into oil droplets and liposome membranes, and a 2024 study found that liposome-delivered Pal-KTTKS stimulated collagen in fibroblasts more than the free peptide or 1 mM ascorbic acid ^[15]. Microneedle pre-treatment increased its delivery into excised human skin by a large multiple in a 2014 study, which is why patches are increasingly used to test peptides ^[14]. A 2021 dermal stability assay found that Pal-KTTKS is degraded by skin proteases, which is one reason formulators encapsulate it ^[16].

Research peptide suppliers sell Matrixyl as a lyophilised powder in the same vial format as injectable peptides. A palmitoylated lipopeptide is a poor candidate for injection on chemical grounds alone: it is surfactant-like, self-assembles into nanostructures in water ^{[8] [9]}, and has never been assessed for what happens when it enters tissue rather than sits on it. No study has injected it in any species. Anyone buying a vial for cosmetic purposes would be reproducing the studied route only by dissolving it into a topical base, at a concentration a thousand times lower than the vial suggests.

In the human trials, Matrixyl side effects were not an issue: the 93-woman study reported that Pal-KTTKS was well tolerated by the skin ^[3], and the later product studies reported no notable irritation ^{[4] [5]}. Fragments of collagen are among the least alarming things to put on skin, and a 2026 paper testing a bioinformatic safety framework for cosmetic peptides used palmitoyl pentapeptide-4 as one of its examples, finding that it shares sequence with the skin’s own matrix proteins and raises none of the toxin or allergen flags that peptides such as conotoxin do ^[17].

That safety picture applies to a few parts per million in a cream. For milligram quantities injected, there are no data, and the theoretical concern is the palmitoyl group: lipopeptides are membrane-active, and related palmitoylated and myristoylated peptides can lyse red blood cells at high concentrations. Two practical points also matter. Pal-KTTKS is degraded quickly by proteases in skin extracts ^{[6] [16]}, so a home-made solution has a short useful life; and the collagen-stimulating signal, if it does reach the dermis, has been studied in the context of normal skin, not in scars or fibrotic conditions where more collagen is not wanted.

Palmitoyl pentapeptide-4 is a permitted cosmetic ingredient in the UK, EU and US, used under the ordinary rules for cosmetics, which require the marketing company to hold safety data but do not require efficacy to be demonstrated. It is not an approved medicine anywhere, is not on the WADA Prohibited List, and has not been the subject of any FDA compounding decision. Claims that a product reverses skin ageing, rather than improving its appearance, would be medicinal claims that no Matrixyl product is licensed to make.

Sold as a research chemical in a vial, it falls under the general rules for research peptides. See our legal status overview, with pages for the UK and the US.

Lyophilised Pal-KTTKS is stored cold, dry and away from light, like other peptides; see how to store peptides. The lipopeptide is poorly soluble in plain water and forms micelles and tapes above about 19 mg/L ^[7], so it will not dissolve cleanly the way a hydrophilic peptide does; cosmetic formulators use glycerol, oils or liposomes. For laboratory use, bacteriostatic water is the usual starting solvent, but expect a cloudy dispersion rather than a clear solution at anything above trace concentrations.

Matrixyl is cheap to make and the trial concentration is tiny, so a small vial goes a very long way in a cream; the meaningful comparison is price per milligram. Compare Matrixyl prices across suppliers, and check listings in the UK and the US; see peptide prices explained for how stores set prices.

A certificate of analysis for Pal-KTTKS should show a measured mass close to 802 g/mol and an HPLC purity figure; a mass near 564 g/mol would mean the plain KTTKS peptide without the palmitoyl group, which does not penetrate skin. Because the Matrixyl name covers several different peptides, check that the COA names palmitoyl pentapeptide-4 rather than palmitoyl tripeptide-1 or tetrapeptide-7. Our guides to reading a COA and third-party testing explain what to look for, and our list of third-party tested suppliers shows which stores publish independent results. For other peptides sold for skin, see peptides for skin.