database / cosmetic
Palmitoyl pentapeptide-4
also known as Matrixyl, pal-KTTKS
Skeletal structure drawn from the computed atomic coordinates in PubChem CID 9897237. Carbons are implicit vertices; hydrogens on carbon are suppressed, as in any structural formula. Nothing here is estimated — every atom sits where PubChem placed it.
Research reference only. The observations below are recorded in the cited literature. Nothing here is advice or a recommendation, and no dosing information is published on this site.
Sequence
KTTKS
Lys-Thr-Thr-Lys-Ser
- hydrophobic
- positive
- negative
- polar
- aromatic
- glycine
- proline
- cysteine
Modified molecule. N-terminally palmitoylated to drive skin penetration; the free pentapeptide is a procollagen I fragment.
Backbone carries modifications, so computed backbone mass is not comparable to the reported mass of the complete molecule.
Molecular data
| molecular formula | C39H75N7O10 |
|---|---|
| molecular weight | 802.1 Da (PubChem) |
| computed backbone mass | 563.65 Da |
| length | 5 residues |
| net charge (pH 7.4) | +2 |
| mean hydropathy | -2 |
| half-life | not characterised |
| delivery route | topical |
| PubChem CID | 9897237 |
| PDB | not characterised |
| UniProt parent | P02452 |
Mechanism
Procollagen fragment reported to signal matrix synthesis in dermal fibroblasts.
Reported targets: dermal fibroblasts
Experimental structure
No experimental structure of this peptide is deposited in the PDB. Nothing is rendered here — a predicted fold would not be a structure, and this site does not draw one.
Parent protein
KTTKS is a fragment of the procollagen I C-terminal propeptide region. UniProt P02452 · 1464 aa
Reported effects
Each row is an outcome described in the literature indexed for this peptide. Reported in the cited work — not a claim, not a recommendation.
| reported outcome | where it appears |
|---|---|
| collagen synthesis | Constrained Evolutionary Design of Matrixyl Analogs: Balancing Permeability … bioRxiv 2026 |
| wrinkle depth reduction | Synergistic Effects of Injectable Platelet-Rich Fibrin and Bioactive Peptide… Molecules (Basel, Switzerland) 2025 |
Literature (8)
Constrained Evolutionary Design of Matrixyl Analogs: Balancing Permeability and Functional Preservation Through Computational Optimization — bioRxiv 2026
abstract not reproduced — this record is not open-access, so it is linked rather than copied.
publisher record ↗ · DOI 10.64898/2026.05.12.724473
Synergistic Effects of Injectable Platelet-Rich Fibrin and Bioactive Peptides on Dermal Fibroblast Viability and Extracellular Matrix Gene Expression: An In Vitro Study — Molecules (Basel, Switzerland) 2025
Facial aging is a multifactorial process involving changes in bone, fat compartments, ligaments, muscles, and skin. Collagen biostimulators, including synthetic agents and autologous platelet concentrates, have gained attention for facial rejuvenation. Injectable platelet-rich fibrin (i-PRF), a second-generation autologous concentrate, has shown promising regenerative properties due to its natural composition and growth factors. Cosmetic peptides, such as palmitoyl pentapeptide-4 (Matrixyl) and Tetrapeptide-21 (GEKG), are also studied for their ability to stimulate collagen synthesis and remodel the extracellular matrix. This in vitro study examined the potential synergistic effects of i-PRF combined with Matrixyl or GEKG on human dermal fibroblast viability, proliferation, and ECM-related gene expression. Fibroblasts were cultured under six conditions: control, i-PRF alone, Matrixyl alo…
open access ↗ · PMID 40871567 · DOI 10.3390/molecules30163415
A framework for the safety evaluation of peptides in cosmetics — Current research in toxicology 2026
As the cosmetic industry replaces traditional animal safety studies with next generation risk assessment approaches, the approach to safety substantiation for peptides used in cosmetic products must also evolve. While the need to provide assurances of safety for local and systemic toxicity endpoints remains the same, adoption of bioinformatic tools developed in the food, agricultural biotechnology, and drug development industries may add to the weight of evidence for the safety substantiation of peptides in cosmetics. Here we review the historical development and safety evaluation of peptides utilized in the cosmetic industry and provide a new safety evaluation framework that incorporates six bioinformatic tools. To test the framework, a variety of peptides (palmitoyl hexapeptide-12, caffeoyl hexapeptide-9, palmitoyl pentapeptide-4, amanitin alpha, conotoxin ArlB, bradykinin, and enkepha…
open access ↗ · PMID 41953401 · DOI 10.1016/j.crtox.2026.100291
Mesenchymal stem cell therapy using Pal-KTTKS-enriched carboxylated cellulose improves burn wound in rat model — Archives of dermatological research 2024
abstract not reproduced — this record is not open-access, so it is linked rather than copied.
publisher record ↗ · PMID 38850353 · DOI 10.1007/s00403-024-03082-1
Dually functionalized dendrimer for stimuli-responsive release of active ingredients into the skin — Acta biomaterialia 2025
abstract not reproduced — this record is not open-access, so it is linked rather than copied.
publisher record ↗ · PMID 39694719 · DOI 10.1016/j.actbio.2024.12.035
Nanostructure and Collagen-Stimulating Activity of Cationic Pentapeptide Lipopeptides — Journal of peptide science : an official publication of the European Peptide Society 2026
The self-assembly in aqueous solutions, cytocompatibility, and collagen production of lipopeptide C16-KTTKS and a variant with arginine substitution for lysine, C16-RTTRS, are investigated. C16-KTTKS is known commercially as Matrixyl and is used in cosmetic formulations as it can stimulate collagen production. The self-assembly and conformations and collagen-stimulating effects of the two lipopeptides in two salt forms, trifluoroacetate (TFA) and acetate, are compared. Lipopeptide C16-KTTKS self-assembles into nanotapes based on a multi-bilayer stacking across a pH range pH 4-7 and micelles at pH 2, with little influence of the counterion. In contrast, C16-RTTRS forms a substantial population of spherical micelles for the acetate salt for pH 2-7, but mainly nanotapes for the TFA salt for pH 4-7. Conditions for hydrogel formation by C16-KTTKS were identified. Both lipopeptides show good c…
open access ↗ · PMID 42317129 · DOI 10.1002/psc.70111
Use of a Serum With the Infinite Glow® Device Improves Signs of Facial Aging: A Split-Face Case Report Using VISIA Analysis — Cureus 2026
abstract not reproduced — this record is not open-access, so it is linked rather than copied.
publisher record ↗ · PMID 42500768 · DOI 10.7759/cureus.111375
Liposome Encapsulation of the Palmitoyl-KTTKS Peptide: Structural and Functional Characterization — Pharmaceutics 2024
In this study, the amphiphilic N-palmitoyl-KTTKS peptide was integrated in the bilayer of egg-derived phosphatidylcholine (PC) vesicles using two different preparation methods, namely thin-film evaporation (TLE) and reverse-phase evaporation (REV). Both the REV and TLE methods allowed for the formation of homogeneous liposome dispersions (PdI < 0.20) with mean hydrodynamic diameters of <100 nm and <200 nm, respectively, a net negative surface charge and a percentage of structured phospholipids higher than 90%. The inclusion of the amphiphilic N-palmitoyl-KTTKS peptide within phospholipid-based vesicles could improve peptide stability and skin delivery. Therefore, the obtained liposomes were evaluated via experiments assessing the synthesis of collagen and the ECM in 3T3-NIH fibroblasts. The obtained results showed that, when delivered with PC liposomes, pal-KTTKS stimulated collagen prod…
open access ↗ · PMID 38399273 · DOI 10.3390/pharmaceutics16020219
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