Palmitoyl Pentapeptide-4
Palmitoyl pentapeptide-4 is the fatty-acid-tagged form of KTTKS, a five-residue fragment of type I procollagen that drives collagen and fibronectin production in fibroblast cultures.
The story starts with the matrix itself. Katayama et al., Journal of Biological Chemistry, 1993 (PMID 8486721) dissected the carboxyl-terminal propeptide of type I collagen and found that the pentapeptide Lys-Thr-Thr-Lys-Ser (KTTKS, residues 212–216) is the minimum sequence needed for potent stimulation of collagen and fibronectin production across several mesenchymal cell types.
Attaching a palmitoyl chain makes the peptide amphiphilic, which is why cosmetic chemists use the palmitoyl form (sold as Matrixyl and listed as palmitoyl pentapeptide-4 on ingredient labels). Vitali et al., Pharmaceutics, 2024 (PMID 38399273) built the palmitoyl-KTTKS peptide into phosphatidylcholine liposomes under 200 nm and reported that, delivered this way, it stimulated collagen production in 3T3-NIH fibroblasts more than the free pentapeptide and more than the ascorbic-acid positive control.
For the wider picture, Gorouhi and Maibach, International Journal of Cosmetic Science, 2009 (PMID 19570099) sort topical cosmetic peptides into four families (signal, enzyme-inhibitor, neurotransmitter-inhibitor, and carrier peptides) and place palmitoyl pentapeptide-4 among the signal peptides, the group designed to mimic matrix-fragment cues to fibroblasts.
For how fibroblast culture assays are read, see Cell-migration readouts, in plain lab language. This note summarizes published cell and formulation research. It is not skincare, dosing, or human-use guidance.