Matrixyl

Dosing from the Literature

Published for wrinkles: 3 ppm in a moisturizer for 12 weeks, tested against the same moisturizer without it in 93 women aged 35–55 (Robinson et al., 2005). Not published: any route but the skin.

Matrixyl dosing applies to topical cosmetic formulations only; no study gives an injected or oral dose. Amounts are given either as a percentage of a commercial Sederma concentrate in the finished product (Matrixyl 3000, synthe'6) or as ppm of the palmitoyl peptide itself.

In the trials cited here, the products were applied to the face twice daily (Trookman et al., 2009; Fu et al., 2010). In Fu's 24-week cohorts, wrinkles kept improving between week 8 and week 24 with both the cosmetic regimen and tretinoin (Fu et al., 2010).

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What It Is

Matrixyl is a trade name owned by Sederma (a subsidiary of Croda International) for a family of palmitoylated short peptides used as active ingredients in topical anti-aging cosmetics. The "original" Matrixyl is Palmitoyl Pentapeptide-4, a five-amino-acid sequence — lysine-threonine-threonine-lysine-serine, abbreviated KTTKS — conjugated at the N-terminus to a 16-carbon palmitic acid chain. The resulting molecule, Pal-KTTKS, has a molecular weight of roughly 802 Da and a CAS registry number of 214047-00-4.

The KTTKS sequence is not an invented synthetic — it corresponds exactly to residues 212 through 216 of the C-terminal propeptide of human type I procollagen, the globular "tail" that is cleaved off procollagen molecules when they are processed into mature collagen fibrils in the extracellular matrix. In the early 1990s, Katayama and colleagues at the University of Tennessee Health Science Center (Memphis) demonstrated that synthetic KTTKS dramatically increased type I and III collagen and fibronectin production by human fibroblasts at concentrations as low as 10^-12 M (Katayama et al., Biochemistry 1991; Katayama et al., J Biol Chem 1993, PMID 8486721). This placed KTTKS in the category of matrikines — extracellular-matrix-derived fragments that feed back on cells to regulate matrix homeostasis.

Native KTTKS is a problem for topical delivery: it is small, highly hydrophilic, and cationic (two lysines), which makes penetration of the lipophilic stratum corneum inefficient. Sederma's technical innovation, commercialized in the late 1990s, was to N-terminally conjugate KTTKS with palmitic acid. The resulting palmitoyl pentapeptide (a chain of 5 amino acids) is amphiphilic — a lipophilic tail attached to a hydrophilic "head" — and in mouse skin extracts it broke down more slowly than the parent peptide, though both degraded quickly (Choi et al., Biomol Ther 2014, PMID 25143811; Mortazavi et al., J Cosmet Sci 2019, PMID 31829923); it still raised collagen production by cultured human fibroblasts (Jones et al., Mol Pharm 2013, PMID 23320752).

Since the launch of the original Matrixyl, Sederma has extended the trade name to cover two further, mechanistically distinct products:

• Matrixyl 3000 — A 1:1 combination of Palmitoyl Tripeptide-1 (Pal-GHK — the palmitoylated form of glycyl-histidyl-lysine, the endogenous matrikine usually paired with copper as GHK-Cu) and Palmitoyl Tetrapeptide-7 (Pal-GQPR — glycyl-glutaminyl-prolyl-arginine, a fragment of immunoglobulin G that modulates IL-6 and inflammatory extracellular matrix breakdown). Marketed as a broader-spectrum matrikine complex than Pal-KTTKS alone.
• Matrixyl synthe'6 — Palmitoyl Tripeptide-38, the palmitoylated tripeptide Pal-Lys-Met(O₂)-Lys ("KMO₂K"; Schagen, 2017), a motif that Sederma derives from sequences found in tenascin-X, laminin, and collagen VI. Marketed as upregulating six structural extracellular matrix components: collagen I, III, IV, fibronectin, hyaluronic acid, and laminin-5.

All Matrixyl variants share three defining features: they are short (3–5 amino acids), they are palmitoylated at the N-terminus for skin permeation, and they are marketed as matrikine-class signaling molecules rather than as "replacement" ingredients (unlike, for example, hyaluronic acid or collagen hydrolysates, which act as bulk substrates). Sederma sells the Matrixyl ingredients to cosmetic makers as concentrates and recommends 3–4% of Matrixyl 3000 or 2% of Matrixyl synthe'6 in the finished product (Sederma, 2020). In the cosmetics industry's 2022 survey, products reported Palmitoyl Pentapeptide-4 at 0.00036–0.0012% (3.6–12 ppm) in leave-on products and at up to 0.0035% (35 ppm) in a hair conditioner (CIR, 2024).

The Matrixyl family sits alongside — and is often co-formulated with — other cosmetic peptides on this site: Argireline (acetyl hexapeptide-8, a SNAP-25-mimetic neuromodulator), Pal-GHK (palmitoylated GHK, the tripeptide-1 component of Matrixyl 3000), Syn-Coll (palmitoyl tripeptide-5), AHK-Cu (alanyl-histidyl-lysine-copper), Syn-Ake (a dipeptide snake-venom mimic), and GHK-Cu itself. The category is properly understood as "cosmetic signaling peptides" — topical actives with real but modest evidence bases designed to modulate skin biology through short-sequence signaling motifs.

Mechanism of Action

The mechanism rests on cell-culture work from the 1990s to 2024, in which fibroblasts (cells that build collagen) and other connective-tissue cells were exposed to KTTKS or Pal-KTTKS (Katayama et al., 1993; Tsai et al., 2007; Jones et al., 2013; Vitali et al., 2024), and on stability and permeation tests in mouse skin (Choi et al., 2014).

• KTTKS is a procollagen I C-propeptide matrikine (a signaling fragment from broken-down skin matrix) — The parent pentapeptide is a sub-fragment of the type I procollagen carboxy-terminal propeptide, residues 212–216 (Katayama et al., 1993). The propeptides of fibril-forming collagens are cleaved off outside the cell and are implicated in feedback regulation of collagen synthesis; in cultured fibroblasts, some synthetic sub-fragments of the C-propeptide raised matrix production and the C-terminal one lowered it (Katayama et al., 1991; Katayama et al., 1993). Katayama's original 1991 and 1993 work identified the 45-amino-acid 197–241 fragment as the most potent positive feedback region, and then dissected KTTKS as the minimum five-residue active sub-fragment (Katayama et al., Biochemistry 1991; Katayama et al., J Biol Chem 1993, PMID 8486721).
• Upregulation of collagen synthesis in fibroblasts — KTTKS is the minimum sequence for strong stimulation of collagen and fibronectin production in several connective-tissue cell types in culture (Katayama et al., 1993), and it raised type I collagen in rat tendon cells (Tsai et al., 2007); Pal-KTTKS raised collagen production by human dermal and corneal fibroblasts in a concentration-dependent way (Jones et al., 2013). In the tendon cells, KTTKS raised α1(I) procollagen mRNA and slowed its breakdown (Tsai et al., 2007). For the larger parent fragment (residues 197–241), the rise in type I and III collagen and fibronectin left total protein synthesis unchanged (Katayama et al., 1993), and procollagen mRNA levels did not change, which its authors read as a post-transcriptional effect (Katayama et al., 1991).
• Fibronectin and glycosaminoglycan upregulation — KTTKS raised fibronectin production along with collagen in cultured cells (Katayama et al., 1993), and Schagen's review lists fibronectin and glycosaminoglycans, as well as elastin, among the matrix components Pal-KTTKS has been reported to stimulate (Schagen, 2017).
• TGF-β upregulation in tendon cells — Work from Tsai and colleagues in rat Achilles tendon cells showed that KTTKS upregulates α1(I) procollagen mRNA expression, slows α1(I) procollagen mRNA degradation, and dose-dependently increases TGF-β secretion into conditioned media — consistent with TGF-β being one of the autocrine/paracrine mediators of the KTTKS effect on the extracellular matrix (Tsai et al., J Orthop Res 2007).
• Type IV collagen and basement membrane support — Schagen's review lists type IV collagen, the main collagen of the basement membrane between epidermis and dermis, among the collagens Pal-KTTKS has been reported to stimulate, and cites a trade-journal report of a four-month vehicle-controlled study in 49 women that linked it to improved collagen IV at the dermal-epidermal junction and denser elastin fibers (Schagen, 2017).
• Self-assembly into nanotape structures above a critical aggregation concentration — Hamley and colleagues at the University of Reading have shown that Pal-KTTKS self-assembles into flat tapes with high β-sheet content (Castelletto et al., Langmuir 2013) and nanotapes in solution (Jones et al., Mol Pharm 2013, PMID 23320752). Collagen production by dermal and corneal fibroblasts rose with Pal-KTTKS concentration close to its critical aggregation concentration, which the authors take as a sign that self-assembly and collagen stimulation are linked (Jones et al., Mol Pharm 2013, PMID 23320752).
• Palmitoyl chain as permeation vehicle and stability enhancer — Palmitoylation turns the water-loving KTTKS (logP -1.6) into a lipophilic molecule (calculated logP about 3.7) (Mortazavi et al., J Cosmet Sci 2019, PMID 31829923). In hairless mouse skin, Pal-KTTKS reached the stratum corneum, epidermis and dermis while KTTKS was not detected in any layer; neither crossed full-thickness skin in 48 hours (Choi et al., Biomol Ther 2014, PMID 25143811). Both were degraded quickly in skin extracts, Pal-KTTKS more slowly: 9.7% remained after two hours in dermal extract, while KTTKS was almost gone within 30 minutes (Choi et al., Biomol Ther 2014, PMID 25143811).
• Wound-healing and α-SMA modulation — Park et al. (Tissue Eng Regen Med 2017, PMID 30603464) found that Pal-KTTKS modulates connective tissue growth factor (CTGF) expression and α-smooth muscle actin (α-SMA) in fibroblasts, suggesting effects on fibroblast-to-myofibroblast trans-differentiation relevant to wound contraction and potentially to scar morphology. The clinical relevance of this finding for cosmetic anti-aging use is unclear.
• Matrixyl 3000 (Pal-GHK + Pal-GQPR) mechanism — Schagen's review describes the Pal-GHK component as stimulating collagen and glycosaminoglycan synthesis, possibly by acting on TGF-β, and the Pal-GQPR component, a palmitoylated fragment of immunoglobulin G (a tetrapeptide, a chain of 4 amino acids), as lowering IL-6 secretion at rest and acting as an anti-inflammatory after UVB exposure (Schagen, 2017).
• Matrixyl synthe'6 (Pal-Tripeptide-38) mechanism — Sederma says Matrixyl synthe'6 stimulates six major constituents of the skin matrix and the dermal–epidermal junction, and lists collagens, hyaluronic acid, fibronectin and laminin as its targets (Sederma, 2022). None of the papers cited here studies how Pal-Tripeptide-38 works; its stated effects come from Sederma.
• What is not well established — None of the papers cited here identifies a receptor for KTTKS or the signaling route from receptor to collagen; the closest is the TGF-β rise seen in rat tendon cells (Tsai et al., 2007). Claims that Matrixyl "activates" a named pathway go beyond what these studies show.

What the Research Shows

The Matrixyl clinical literature is small, industry-adjacent, and technically modest — but it is not empty. There are two peer-reviewed randomized trials, both run by Procter & Gamble: a 12-week split-face trial of 3 ppm Pal-KTTKS against the same moisturizer without it in 93 women (Robinson et al., 2005), and an 8-week comparison of a multi-ingredient regimen containing it with 0.02% tretinoin in 196 women (Fu et al., 2010). The rest are smaller or open studies, conference abstracts and narrative reviews. Every clinical study cited here was run or paid for by a company selling a product that contains it, and their endpoints are expert or investigator grading, image analysis and self-assessment (Robinson et al., 2005; Fu et al., 2010; Trookman et al., 2009).

• Robinson 2005 — 12-week split-face RCT in photoaged Caucasian women — Robinson and colleagues at Procter & Gamble's Miami Valley Laboratories conducted a 12-week, double-blind, placebo-controlled, split-face, left-right randomized clinical study in 93 Caucasian women aged 35–55 (Int J Cosmet Sci 2005, PMID 18492182). Each subject applied moisturizer containing 3 ppm Pal-KTTKS to one half of the face and matching vehicle moisturizer to the other. Pal-KTTKS produced statistically significant improvement versus vehicle on quantitative wrinkle / fine-line measures by both technical image analysis and expert grader evaluation. Subject self-assessment showed the same pattern. Skin tolerability was equivalent to vehicle. This remains the single most-cited clinical support for Matrixyl's cosmetic claims.
• Osborne 2005 — 8-week split-face moisturizer study (n=60) — Osborne and colleagues (also at P&G) evaluated a daily-use facial moisturizer containing Pal-KTTKS combined with niacinamide versus moisturizer alone in 60 women aged 35–65, applied twice daily for 8 weeks in a split-face, randomized, round-robin design (Osborne, Robinson, Mullins, Raleigh; J Am Acad Dermatol 2005 abstract/poster, published in JAAD as part of the AAD meeting proceedings). The moisturizer containing Pal-KTTKS plus niacinamide produced greater improvement in skin texture, fine lines, and wrinkle appearance at the cheek and periorbital area than moisturizer alone. Study design was technically sound for a cosmetic endpoint but used subjective expert-grading and self-report as primary outcomes.
• Lupo 2005 — Dermatologic Surgery narrative review — Mary P. Lupo of Tulane University reviewed the emerging cosmeceutical peptide category (Dermatol Surg 2005, PMID 16029675). Pal-KTTKS was positioned as a signal-peptide class representative; the review concluded that there "does seem to be science that shows that these peptide cosmeceuticals have the potential to improve the appearance of aging skin" while emphasizing that stability, penetration, and bioactivity at the target must all be demonstrated for clinical benefit.
• Lupo & Cole 2007 — Dermatologic Therapy update — Lupo and Cole updated the category in 2007 (Dermatol Ther 2007, PMID 18045359), grouping cosmeceutical peptides into signal peptides, neurotransmitter-affecting peptides, and carrier peptides. The review reaffirms the signal-peptide classification of Pal-KTTKS and notes that while their benefits "may not be as rigorously tested as most FDA-regulated drugs, the evidence to support their use is growing."
• Trookman 2009 — Topical facial serum (n=37, three months, open-label) — Trookman, Rizer, Ford, Ho, and Gotz evaluated a topical line treatment containing Pal-KTTKS among other actives in a three-month, single-centre, open-label study of 37 women aged 33 to 45 with fine and coarse periocular and perioral wrinkles (J Clin Aesthet Dermatol 2009, PMID 20729942). Investigator assessments improved over baseline within minutes of the first application and kept improving through months 1 and 3. There was no control group, and the formulation contained growth factors, antioxidants, hyaluronic acid spheres and a second peptide, so the effect cannot be attributed to Pal-KTTKS.
• Fu 2010 — Niacinamide/peptide/retinyl propionate vs 0.02% tretinoin (n=196) — Fu, Hillebrand, Raleigh and colleagues ran an 8-week randomized, controlled comparative trial pitting a cosmetic niacinamide/peptide (Pal-KTTKS)/retinyl-propionate regimen against prescription 0.02% tretinoin in 196 women aged 40–65 with moderate to moderately severe periorbital wrinkles; 25 self-selected women in each group continued to 24 weeks (Br J Dermatol 2010, PMID 20374604). Both regimens improved wrinkles from baseline; at 8 weeks the cosmetic regimen improved them significantly more than tretinoin by expert grading, and at 24 weeks the two cohorts did not differ. Tolerability favored the cosmetic regimen. The trial was funded by Procter & Gamble, and the subjects were not blinded.
• Gorouhi & Maibach 2009 — Int J Cosmet Sci peptide review — Gorouhi and Maibach (UCSF Dermatology) systematically categorized topical peptides for aged skin into signal, neurotransmitter, carrier, and enzyme-inhibitor groups (Int J Cosmet Sci 2009, PMID 19570099). Pal-KTTKS is classified as a signal peptide; the review is cautiously positive, repeatedly notes the industry sponsorship of the primary efficacy literature, and emphasizes the need for independent confirmation.
• Jones 2013 — Collagen stimulation and nanotape self-assembly — Jones, Castelletto, Connon, and Hamley (University of Reading) directly measured collagen production by human dermal and corneal fibroblasts exposed to Pal-KTTKS across a concentration range (Mol Pharm 2013, PMID 23320752). Pal-KTTKS stimulated collagen in a dose-dependent fashion with maximum effect near the critical aggregation concentration at which it self-assembles into β-sheet nanotapes, supporting a supramolecular signaling mechanism.
• Choi 2014 — Dermal stability and skin permeation — Choi and colleagues measured dermal stability and in vitro skin permeation of KTTKS and Pal-KTTKS through hairless mouse skin (Biomol Ther 2014, PMID 25143811). Both were rapidly degraded in skin extracts, Pal-KTTKS more slowly than KTTKS; neither crossed full-thickness skin in 48 hours, but Pal-KTTKS was found in the stratum corneum (4.2 µg/cm²), epidermis (2.8 µg/cm²) and dermis (0.3 µg/cm²), where KTTKS was not detected — experimental support for the palmitoylation-as-delivery-vehicle design rationale.
• Park 2017 — Wound contractility and myofibroblast signaling — Park, An, and Cho Lee studied Pal-KTTKS effects on fibroblast contractility, CTGF expression, and α-SMA expression in vitro (Tissue Eng Regen Med 2017, PMID 30603464), reporting modulation of myofibroblast trans-differentiation at pharmacologically relevant concentrations.
• Tałałaj 2019 — KTTKS analogue structure-activity series — Tałałaj and colleagues synthesized a series of KTTKS analogues with different N-terminal lipid modifications (acetyl, lipoyl, palmitoyl) and evaluated cytotoxicity and proteolytic activity against urokinase, thrombin, trypsin, plasmin, t-PA, and kallikrein (Molecules 2019, PMID 31618846). The palmitoyl variant maintained favorable cytotoxicity and added plasmin-inhibitory activity — a new potential mechanistic dimension beyond pure collagen stimulation.
• Vitali 2024 — Liposome encapsulation of Pal-KTTKS — Vitali and colleagues characterized liposome-encapsulated Pal-KTTKS formulations for enhanced stability and delivery, demonstrating in vitro collagen-I stimulation in 3T3-NIH fibroblasts and maintained cell viability at cosmetically relevant concentrations (Pharmaceutics 2024, PMID 38399273).

Human Data

Matrixyl's human data are entirely topical-cosmetic. There are no systemic or parenteral human trials — the route is topical only, the indications are cosmetic (fine lines, wrinkles, texture, firmness), and the primary endpoints are dermatologist or subject visual assessments. The most important trials:

• Robinson 2005 (PMID 18492182) — 93 Caucasian women, 35–55 years old, 12 weeks, double-blind split-face randomized vehicle-controlled. 3 ppm Pal-KTTKS in moisturizer vs identical moisturizer vehicle. Significant Pal-KTTKS superiority on quantitative image analysis wrinkle/fine-line reduction and on expert-grader assessment. No safety signal.
• Osborne 2005 (JAAD abstract / AAD proceedings) — 60 women, 35–65 years, 8 weeks, split-face, randomized round-robin. Moisturizer + niacinamide + Pal-KTTKS vs moisturizer alone. Significant improvement in skin texture, fine lines, and cheek/eye wrinkle appearance. Combination design cannot isolate Pal-KTTKS contribution.
• Trookman 2009 (PMID 20729942) — Three-month, single-centre, open-label evaluation of a Pal-KTTKS-containing facial line treatment in 37 women. Investigator assessments of periocular and perioral wrinkles improved within minutes of the first application and kept improving through months 1 and 3. No placebo arm, and the formulation contained growth factors, antioxidants, hyaluronic acid spheres and a second peptide.
• Fu 2010 (PMID 20374604) — 196 women aged 40–65, 8-week randomized controlled head-to-head trial of a cosmetic niacinamide/Pal-KTTKS/retinyl-propionate regimen vs prescription 0.02% tretinoin, with 25 self-selected women per group continuing to 24 weeks. Both regimens improved wrinkles from baseline on expert-grader and image analysis endpoints; at 8 weeks the cosmetic regimen did significantly better than tretinoin by expert grading, and at 24 weeks the cohorts did not differ. Tolerability clearly favored the cosmetic regimen.
• Ex vivo / in vitro-to-clinical bridging — Several published series have used short-duration (4–8 week) bioinstrumentation studies (corneometer hydration, cutometer elasticity, silicone replica roughness) rather than expert-grader wrinkle scales. These report favorable directional effects for Pal-KTTKS-containing formulations but are not themselves randomized clinical trials.
• Matrixyl 3000 (Pal-GHK + Pal-GQPR) human data — Sederma reports that in its 2-month studies the surface occupied by deep wrinkles fell by 45% in women and by nearly 30% in men; Schagen's review, citing a patent, describes a blind, randomized study in 28 volunteers with the product on one half of the face and a placebo cream on the other (Schagen, 2017). These results circulate in the cosmetic literature but have not been replicated in an independent peer-reviewed vehicle-controlled RCT at the level of the Robinson 2005 Pal-KTTKS trial.
• Matrixyl synthe'6 (Pal-Tripeptide-38) human data — Supplier-disclosed 2-month studies report reductions in forehead and crow's-feet wrinkle depth. Independent peer-reviewed vehicle-controlled RCT data at the Robinson 2005 level of rigor are not currently available.
• Systemic exposure — No measurable systemic absorption has been demonstrated from cosmetic concentrations of Pal-KTTKS. The molecule is too large and too lipophilic-at-the-tail, too hydrophilic-at-the-head to cross the intact stratum corneum in pharmacologically meaningful amounts under normal cosmetic use conditions. Bloodwork changes are not expected and have not been reported.

The 2024 CIR (Cosmetic Ingredient Review) expert panel assessment of myristoyl pentapeptide-4, palmitoyl pentapeptide-4, and pentapeptide-4 compiled supplier-provided and published safety and exposure data and concluded these ingredients are safe as used in cosmetic formulations at current concentrations and exposure patterns. The CIR review is the most comprehensive single consolidation of the safety-and-exposure side of the Matrixyl human data.

Reconstitution & Storage

Matrixyl is not reconstituted like an injectable peptide: Sederma sells its Matrixyl ingredients to cosmetic makers as concentrates, used at a few percent of the finished product (Sederma, 2020). The peptide itself is a white powder (CIR, 2024). No source on this page gives storage temperatures or shelf lives for the ingredients or for finished products.

• Incompatibilities — Formulation guides describe keeping it out of high-pH (>7.5) formulations and away from strong oxidizers such as benzoyl peroxide and hypochlorites. In Fu's trial, the regimen's products combined it with niacinamide, carnosine, retinyl propionate, sunscreens and vitamins C and E, and were better tolerated than 0.02% tretinoin (Fu et al., 2010).
• Discarding — Some product labels advise discarding a product that turns cloudy, changes color or separates.

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Side Effects & Risks

Most safety data are supplier tests compiled by the Cosmetic Ingredient Review: in them the peptide was not mutagenic and caused no sensitization in human repeated patch tests (CIR, 2024). The Cosmetic Ingredient Review (CIR) Expert Panel has assessed myristoyl pentapeptide-4, palmitoyl pentapeptide-4, and pentapeptide-4 and concluded they are safe as used in current cosmetic formulations (CIR Safety Assessment, 2024 and preceding documents).

• Skin tolerance — In Robinson 2005 (n=93 split-face, 12 weeks), the 3 ppm moisturizer was "well tolerated by the skin" (Robinson et al., 2005). In Fu's 8-week trial in 196 women, redness rose at week 2 with both the regimen containing it and tretinoin, then returned to baseline from week 4 with the cosmetic regimen, which was better tolerated than tretinoin by all measures (Fu et al., 2010); Trookman's open study in 37 women reported no treatment-related adverse events (Trookman et al., 2009). Both of those products contained other actives.
• Contact irritation / sensitization — In the CIR's compilation, a trade-name mixture containing 0.01% of the peptide caused no irritation or sensitization in an occlusive repeated patch test in 51 people, a formulation containing 0.12% (the Pal-KTSKS sequence), tested at 15%, caused none in 106, and in a 10-person irritation test one person had very slight redness (CIR, 2024). A PubMed search finds no case report of allergy or contact dermatitis attributed to Pal-KTTKS alone (October 2026).
• Periorbital use — Products reported it in 31 eye-area uses, at up to 0.0012% in eye lotions. It did not irritate rabbit eyes at 0.01% or a human corneal-cell model, while egg-membrane (HET-CAM) tests rated a trade-name mixture containing 0.01% moderately irritating and a 0.12% formulation slightly irritating (CIR, 2024).
• Pregnancy and lactation — No study has tested it in pregnancy or breastfeeding (PubMed, October 2026). The CIR found no developmental or reproductive toxicity study and judged such data unnecessary, given the low use concentrations, the limited skin penetration seen in lab tests and negative genotoxicity tests (CIR, 2024).
• Pediatric use — The human studies cited here enrolled adult women: aged 35–55 (Robinson et al., 2005), 40–65 (Fu et al., 2010) and 33–45 (Trookman et al., 2009). No use in baby products was reported to the CIR (CIR, 2024).
• Drug interactions — No interaction study has been published (PubMed, October 2026). In a lab test, the peptide did not pass through full-thickness mouse skin (Choi et al., 2014).
• Photosensitivity — A sample sold under the same ingredient name (the Pal-KTSKS sequence) absorbed no UVA or UVB light in a spectrum test and was predicted not to be phototoxic; no human photosensitivity test is reported (CIR, 2024).
• Long-term safety — The CIR found no subchronic, chronic or carcinogenicity study (CIR, 2024). The longest use in a trial cited here is 24 weeks, in a cohort of 25 women (Fu et al., 2010).
• Not a drug — Matrixyl is sold as a cosmetic ingredient, and FDA has approved no drug containing it (Drugs@FDA, October 2026). Under US law, a product's intended use decides: a claim to improve the appearance of fine lines, wrinkles or texture is a cosmetic claim, while a claim to treat disease or to affect the structure or any function of the body makes it a drug (FDA, "Is It a Cosmetic, a Drug, or Both?").
• Growth-factor concerns — Pal-KTTKS is a five-amino-acid fragment, not a growth factor, but in rat tendon cells KTTKS raised secretion of the growth factor TGF-β (Tsai et al., 2007). The CIR found no carcinogenicity study (CIR, 2024).

Bloodwork & Monitoring

No trial, label or guideline sets monitoring for Matrixyl. The trials cited here measured wrinkles by expert grading of photographs, image analysis and self-assessment (Robinson et al., 2005; Fu et al., 2010), and Fu's trial also tracked redness, dryness and water loss through the skin (Fu et al., 2010). In a lab test, the peptide did not pass through full-thickness mouse skin (Choi et al., 2014).

Commonly Stacked With

Matrixyl is sold in finished products alongside other peptide and non-peptide actives. Each card gives the basis for the pairing and what is published on it.

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Legal Status

Related Compounds

Matrikine and related cosmetic peptides to cross-reference:

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References

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. (The defining paper identifying KTTKS as the minimum collagen-stimulating sub-fragment of the type I procollagen C-propeptide.)
2. 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. (The 93-subject 12-week split-face vehicle-controlled RCT of 3 ppm Pal-KTTKS — the single best clinical-trial support for Matrixyl.)
3. Lupo MP. Cosmeceutical peptides. Dermatol Surg. 2005;31(7 Pt 2):832-836. PMID: 16029675. (Category-defining review placing Pal-KTTKS in the signal-peptide class of cosmeceuticals.)
4. Lupo MP, Cole AL. Cosmeceutical peptides. Dermatol Ther. 2007;20(5):343-349. PMID: 18045359. (Updated Dermatologic Therapy review of signal, neurotransmitter-affecting, and carrier peptides.)
5. Gorouhi F, Maibach HI. Role of topical peptides in preventing or treating aged skin. Int J Cosmet Sci. 2009;31(5):327-345. PMID: 19570099. (UCSF Dermatology systematic review of topical peptides for aged skin, including Pal-KTTKS signal-peptide class.)
6. Trookman NS, Rizer RL, Ford R, Ho E, Gotz V. Immediate and Long-term Clinical Benefits of a Topical Treatment for Facial Lines and Wrinkles. J Clin Aesthet Dermatol. 2009;2(3):38-43. PMID: 20729942. (8-week topical treatment clinical study including palmitoyl pentapeptide active; SkinMedica-sponsored.)
7. Fu JJ, Hillebrand GG, Raleigh P, Li J, Marmor MJ, Bertucci V, Grimes PE, Mandy SH, Perez MI, Weinkle SH, Kaczvinsky JR. 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. (24-week head-to-head RCT of cosmetic Pal-KTTKS-containing regimen vs prescription tretinoin.)
8. 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. (Direct fibroblast collagen-production dose-response for Pal-KTTKS linked to critical-aggregation-concentration self-assembly.)
9. 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. (Demonstrates palmitoylation as stability and permeation enhancer relative to unmodified KTTKS.)
10. Park H, An E, Cho Lee AR. Effect of Palmitoyl-Pentapeptide (Pal-KTTKS) on Wound Contractile Process in Relation with Connective Tissue Growth Factor and α-Smooth Muscle Actin Expression. Tissue Eng Regen Med. 2017;14(1):73-80. PMID: 30603464. (CTGF / α-SMA modulation and fibroblast-to-myofibroblast effects of Pal-KTTKS.)
11. Tałałaj U, Uscinowicz P, Bruzgo I, Surazynski A, Zareba I, Markowska A. The Effects of a Novel Series of KTTKS Analogues on Cytotoxicity and Proteolytic Activity. Molecules. 2019;24(20):3698. PMID: 31618846. (Structure-activity series of KTTKS analogues with acetyl / lipoyl / palmitoyl N-terminal modifications.)
12. Mortazavi SM, Kobarfard F, Maibach HI, Moghimi HR. Effect of Palmitic Acid Conjugation on Physicochemical Properties of Peptide KTTKS: A Preformulation Study. J Cosmet Sci. 2019;70(6):299-312. PMID: 31829923. (Physicochemical characterization of palmitoyl conjugation effects on KTTKS — lipophilicity, stability, aggregation behavior.)
13. Vitali A, Paolicelli P, Bigi B, Trilli J, Di Muzio L, Carriero VC, Casadei MA, Petralito S. Liposome Encapsulation of the Palmitoyl-KTTKS Peptide: Structural and Functional Characterization. Pharmaceutics. 2024;16(2):219. PMID: 38399273. (Liposomal delivery system for Pal-KTTKS with maintained fibroblast collagen-stimulating activity.)
14. Tsai WC, Hsu CC, Chung CY, Lin MS, Li SL, Pang JH. The pentapeptide KTTKS promoting the expressions of type I collagen and transforming growth factor-beta of tendon cells. J Orthop Res. 2007;25(12):1629-1634. doi:10.1002/jor.20455. (KTTKS upregulates α1(I) procollagen, stabilizes procollagen mRNA, and increases TGF-β secretion in tendon-derived fibroblasts — mechanistic support extending beyond skin.)
15. Osborne R, Mullins L, Jarrold B, Lintner K. In vitro skin structure benefits with a new antiaging peptide, Pal-KT. J Am Acad Dermatol. 2005;52(3 Suppl):P34. (AAD-meeting abstract on Pal-KT / Pal-KTTKS cosmetic evaluation; Procter & Gamble / Sederma collaboration.)
16. Osborne R, Robinson LR, Mullins L, Raleigh P. Use of a facial moisturizer containing palmitoyl pentapeptide improves the appearance of aging skin. J Am Acad Dermatol. 2005;52(3 Suppl):P112. (AAD-meeting abstract; 60-subject 8-week split-face Pal-KTTKS + niacinamide moisturizer evaluation.)
17. Personal Care Products Council, Cosmetic Ingredient Review Expert Panel. Safety Assessment of Myristoyl Pentapeptide-4, Palmitoyl Pentapeptide-4, and Pentapeptide-4 as Used in Cosmetics. CIR Final Report. March 2024. (Consolidated safety, exposure, and efficacy data for the Pal-KTTKS ingredient family — the most comprehensive regulatory-safety review available.)
18. Schagen SK. Topical Peptide Treatments with Effective Anti-Aging Results. Cosmetics. 2017;4(2):16. doi:10.3390/cosmetics4020016. (Category review situating Pal-KTTKS, Matrixyl 3000, and Matrixyl synthe'6 in the topical anti-aging peptide landscape.)
19. Katayama K, Seyer JM, Raghow R, Kang AH. Regulation of extracellular matrix production by chemically synthesized subfragments of type I collagen carboxy propeptide. Biochemistry. 1991;30(29):7097-7104. doi:10.1021/bi00243a009. (The foundational 1991 paper that identified the procollagen I C-propeptide 197–241 region as a positive extracellular-matrix regulator, leading directly to the 1993 KTTKS-minimum-sequence paper.)
20. Castelletto V, Hamley IW, Whitehouse C, Matts PJ, Osborne R, Baker ES. Self-Assembly of Palmitoyl Lipopeptides Used in Skin Care Products. Langmuir. 2013;29(29):9149-9155. doi:10.1021/la401771j. (Supramolecular self-assembly behavior of C16-GHK, C16-KT, and C16-KTTKS palmitoyl lipopeptides used in commercial Matrixyl-class cosmetics.)
21. FDA. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act (503A categories list), versions updated April 15, April 22 and May 14, 2026. fda.gov/media/94155/download. Read October 3, 2026. (Notice that 12 peptides would leave Category 2 because their nominations were withdrawn; their removal; GHK-Cu, except injectable, back in Category 1.)
22. Sederma (Croda International). Choose your Matrixyl (recommended use levels for Matrixyl 3000, Matrixyl 3000 Lipo, Matrixyl 3000 Free and Matrixyl synthe'6). matrixylinside.com, archived August 11, 2020. web.archive.org/web/20200811041851/https://www.matrixylinside.com/en-gb/manufacturers/choose-your-matrixyl. Read October 4, 2026. (The supplier's own use levels: 3–4% for Matrixyl 3000, 2% for Matrixyl synthe'6.)
23. Sederma (Croda International). Matrixyl 3000 and Matrixyl synthe'6 product pages (characteristics and formulation attributes). matrixylinside.com, archived May 28, 2022. web.archive.org/web/20220528102437/https://www.matrixylinside.com/en-gb/matrixyl-range/matrixyl-3000 and web.archive.org/web/20220528100057/https://www.matrixylinside.com/en-gb/matrixyl-range/matrixyl-synthe6. Read October 4, 2026. (Solubility, preservative-free supply and the supplier's stated targets.)

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