Matrixyl (Pal-KTTKS)
Also known as: Palmitoyl Pentapeptide-4, Pal-KTTKS, Palmitoyl-Lys-Thr-Thr-Lys-Ser, Palmitoyl pentapeptide-3, C16-KTTKS, Pentapeptide-4
Cosmetic matrikine peptide (lipopeptide signal peptide derived from collagen pro-alpha1(I) chain)
What it is
Matrixyl is a cosmetic peptide used in anti-aging skincare products to reduce wrinkles and firm skin. It works by signaling skin cells to produce more collagen, the structural protein that keeps skin smooth and plump. Matrixyl is a cosmetic ingredient regulated similarly to other skincare actives — it is not a drug, requires no prescription, and has never been approved (or reviewed) by drug regulators.
The scientific side
Matrixyl (Pal-KTTKS) is described as a matrikine lipopeptide derived from the pro-alpha1(I) chain of type I collagen that acts as a cell-signaling molecule to upregulate extracellular matrix synthesis in dermal fibroblasts. The palmitoyl fatty acid chain conjugated to the KTTKS pentapeptide sequence improves lipophilicity (logP ~3.7 vs. -1.6 for unconjugated KTTKS) and surface activity, with a critical micelle concentration of ~0.024 mM, which may facilitate membrane interaction and enhance dermal penetration through the stratum corneum. Skin permeation data show pal-KTTKS distributes across skin layers after topical application: 4.2 ± 0.7 μg/cm² in stratum corneum, 2.8 ± 0.5 μg/cm² in epidermis, and 0.3 ± 0.1 μg/cm² in dermis, with greater stability than the unconjugated peptide. The primary downstream mechanism is stimulation of collagen and extracellular matrix production in human dermal fibroblasts. Collagen-stimulating activity is inter-related with self-assembly behavior: C16-KTTKS forms nanotapes via multi-bilayer stacking at physiological pH 4–7, and collagen stimulation peaks near the critical aggregation concentration (PMID 23320752; 42317129). In aged adult fibroblasts, Pal-KTTKS combined with niacinamide and olive oil derivative upregulated mRNA for COL1A1, COL3A1, COL5A1, COL14A1, ELN, LOXL2, SOD2, NAMPT, and TGFBR3 while reducing MMP1 expression, partially restoring gene expression profiles toward neonatal levels. Peptide combination studies show synergistic gene expression changes in both keratinocytes and fibroblasts, activating NRF2-mediated oxidative stress response pathways and restoring cellular ATP depleted by reactive oxygen species. In wound models, Pal-KTTKS reduces myofibroblast differentiation — α-SMA-positive stress fibers were reduced twofold at 0.1 μM (75 ± 7.1% to 38.6 ± 16.1%, p<0.05), indicating a role in modulating the wound contractile process and potentially limiting fibrotic scarring. A 12-week randomized double-blind split-face clinical study in 93 Caucasian women aged 35–55 demonstrated significant improvement in wrinkles and fine lines versus placebo at 3 ppm concentration. Liposomal encapsulation further enhances collagen-stimulating activity beyond free peptide.
Class: Cosmetic matrikine peptide (lipopeptide signal peptide derived from collagen pro-alpha1(I) chain)
Administration & storage
- Storage
- Pal-KTTKS decomposes near 150–154°C without prior melting; finished cosmetic products should be stored per manufacturer guidance, typically at room temperature away from direct heat and light. Aqueous formulations may require preservatives and antioxidants to maintain stability.
- Cautions
- No systemic absorption at meaningful levels from topical use based on skin permeation data,Well tolerated in 12-week human RCT with no adverse reactions reported at 3 ppm,None of the tested KTTKS analogue peptides were cytotoxic to fibroblasts in vitro,Patch testing recommended for individuals with known cosmetic ingredient sensitivities — standard cosmetic precaution,No published systemic safety studies; intended only for topical cosmetic use
Legal & regulatory status
Not a drug; regulated as a cosmetic ingredient under the Federal Food, Drug, and Cosmetic Act. The FDA does not pre-approve cosmetic ingredients. Matrixyl (Pal-KTTKS / Palmitoyl Pentapeptide-4) appears on the INCI…
Not listed as a banned substance — cosmetic peptide with no known performance-enhancing use. Matrixyl is applied topically to skin and does not enter systemic circulation at meaningful levels based on skin permeation…
Not stated in reviewed literature — requires manual verification. As a cosmetic ingredient, would be subject to the Canada Consumer Product Safety Act and Health Canada's cosmetic ingredient notification process, not…
What it's studied for
- Reduction of facial wrinkles and fine lines (human clinical trial, topical) Human RCT
- 12-week double-blind, placebo-controlled split-face RCT in 93 Caucasian females aged 35–55 showed pal-KTTKS at 3 ppm in moisturizer provided significant improvement vs. placebo for reduction of wrinkles and fine lines by both quantitative technical and expert grader image analysis; well tolerated with no adverse reacti PMID 18492182 Robinson LR et al., International Journal of Cosmetic Science (2005)
- Stimulation of dermal collagen and extracellular matrix production (in vitro, human fibroblasts) Mechanistic only
- C16-KTTKS stimulated collagen production in human fibroblasts in a concentration-dependent manner near the critical aggregation concentration; self-assembly into nanotapes and collagen-stimulating activity were found to be inter-related mechanistically. PMID 23320752 Jones RR et al., Molecular Pharmaceutics (2013)
- C16-KTTKS formed nanotapes via multi-bilayer stacking at pH 4–7 and demonstrated good cytocompatibility to fibroblasts; collagen production was stimulated in human dermal fibroblasts at 0.0062 wt% concentration. PMID 42317129 de Mello LR et al., Journal of Peptide Science (2026)
- Pal-KTTKS delivered in phosphatidylcholine liposomes stimulated collagen production more than free pentapeptide in fibroblast cultures, indicating liposomal encapsulation as a viable strategy to enhance the peptide's cosmeceutical efficacy. PMID 38399273 Vitali A et al., Pharmaceutics (2024)
- Restoration of collagen gene expression in aged fibroblasts and reduction of matrix metalloproteinase activity (in vitro) Mechanistic only
- Pal-KTTKS combined with niacinamide and olive oil derivative upregulated COL1A1, COL3A1, COL5A1, COL14A1, ELN, LOXL2, SOD2, NAMPT, and TGFBR3 mRNA expression while downregulating MMP1 in aged adult fibroblasts; effects matched or approached neonatal fibroblast expression levels. PMID 23786618 Osborne R et al., British Journal of Dermatology (2013)
- Combination of Pal-KTTKS with Ac-PPYL (±niacinamide) produced synergistic gene expression changes in keratinocytes and fibroblasts, activating NRF2-mediated oxidative stress pathways and restoring ATP depleted by reactive oxygen species; transcriptomics matched fractional laser treatment profiles. PMID 34272744 Flagler MJ et al., International Journal of Cosmetic Science (2021)
- Wound healing — enhanced wound closure and collagen deposition (animal models) Animal studies only
- Matrixyl in patch and cream formulations improved wound healing from 63.5% up to 81.81% in treatment groups vs. negative control (P<0.05 and P<0.001) over 21 days in rats; both formulations outperformed the positive control Comfeel (P<0.05); H&E staining showed skin appendage rejuvenation and improved re-epithelializat PMID 35874243 Kachooeian M et al., ACS Omega (2022)
- MSC-seeded pal-KTTKS-enriched carboxylated cellulose composites over 14 days in rat burn wounds produced significantly alleviated inflammation, increased collagen deposition, and improved angiogenesis versus controls; MSC-KTTKS-CBC combination was superior to all individual treatments. PMID 38850353 Rasouli M et al., Archives of Dermatological Research (2024)
- Cycloalkane-based lipopeptide analogue of KTTKS (DDKT) significantly increased regenerated hair follicles and blood vessel numbers in diabetic rat wound models by day 20 compared to controls, suggesting wound regenerative utility of KTTKS-scaffold lipopeptides. PMID 39422705 Adak A et al., ACS Applied Materials & Interfaces (2024)
- Modulation of wound contraction and myofibroblast differentiation (in vitro) Mechanistic only
- Pal-KTTKS at 0.1 μM reduced α-SMA-positive myofibroblast stress fibers twofold (75 ± 7.1% vs. 38.6 ± 16.1%, p<0.05) in fibroblast cultures; the inhibitory effect diminished at higher concentration (0.5 μM), indicating a narrow therapeutic dose window for anti-fibrotic applications. PMID 30603464 Park H et al., Tissue Engineering and Regenerative Medicine (2017)
- Antimicrobial / antibiofilm activity (KTTKS-scaffold derivatives, in vitro) Mechanistic only
- KTTKS-based peptide 3.1-PP4 demonstrated MIC values as low as 1.0–2.1 μM against E. coli and P. aeruginosa and 0.5–4.1 μM against multidrug-resistant Gram-negative clinical isolates, retaining collagen-inducing properties at sub-MIC concentrations and showing low fibroblast toxicity. PMID 31481944 Gomes A et al., Frontiers in Microbiology (2019)
- Imidazolium-based ionic liquid conjugates of KTTKS demonstrated potent activity against antibiotic-susceptible strains and multidrug-resistant clinical isolates; collagenesis-inducing effects were comparable to or stronger than reference Matrixyl in vitro. PMID 35950860 Gomes A et al., Microbiology Spectrum (2022)
Safety signals
- Limited dermal penetration — systemic exposure negligible
- Dose-dependent reversal of myofibroblast inhibition at higher concentrations
- No cytotoxicity to fibroblasts across a series of KTTKS analogues
- Well tolerated in 12-week placebo-controlled human study
Contraindications
About these dose ranges
Dose ranges below reflect commonly reported community protocols. Where published research cites a specific dose, the PMID is linked. Doses without citations are not clinical recommendations — they reflect what practitioners and researchers commonly report using.
Community-reported dosing
| Route | Dose | Frequency / Duration | Population / context | Source tier |
|---|---|---|---|---|
| topical | 3 ppm in moisturizer formulation | 12 weeks | Study | Research |
| cell culture medium | 0.0062 wt% (approximately 62 ppm) | not specified | Study | Research |
| cell culture medium | 0.1 μM (inhibitory) — 0.5 μM (effect attenuated) | not specified | Study | Research |
| topical (ex vivo human skin) | Measured distribution: 4.2 ± 0.7 μg/cm² stratum corneum; 2.8 ± 0.5 μg/cm² epidermis; 0.3 ± 0.1 μg/cm² dermis | single application | Study | Research |
| topical application to face | typically 5–20 ppm in finished cosmetic formulation (lowest studied effective dose: 3 ppm per PMID 18492182) | once or twice daily | skincare users seeking anti-aging cosmetic peptides |
All studies (15)
- PMID 18492182 Human RCT
Reduction of facial wrinkles and fine lines (human clinical trial, topical) - PMID 23320752 Mechanistic only
Stimulation of dermal collagen and extracellular matrix production (in vitro, human fibroblasts) - PMID 23786618 Mechanistic only
Restoration of collagen gene expression in aged fibroblasts and reduction of matrix metalloproteinas - PMID 25143811
- PMID 30603464 Mechanistic only
Modulation of wound contraction and myofibroblast differentiation (in vitro) - PMID 31481944 Mechanistic only
Antimicrobial / antibiofilm activity (KTTKS-scaffold derivatives, in vitro) - PMID 31618846
- PMID 31829923
- PMID 34272744 Mechanistic only
Restoration of collagen gene expression in aged fibroblasts and reduction of matrix metalloproteinas - PMID 35874243 Animal studies only
Wound healing — enhanced wound closure and collagen deposition (animal models) - PMID 35950860 Mechanistic only
Antimicrobial / antibiofilm activity (KTTKS-scaffold derivatives, in vitro) - PMID 38399273 Mechanistic only
Stimulation of dermal collagen and extracellular matrix production (in vitro, human fibroblasts) - PMID 38850353 Animal studies only
Wound healing — enhanced wound closure and collagen deposition (animal models) - PMID 39422705 Animal studies only
Wound healing — enhanced wound closure and collagen deposition (animal models) - PMID 42317129 Mechanistic only
Stimulation of dermal collagen and extracellular matrix production (in vitro, human fibroblasts)