A pretty famous and better-researched peptide consisting of five amino acids (the building blocks of all proteins). It was created in a joint effort by the french ingredient supplier, Sederma and the cosmetics industry big shot, Procter&Gamble.
The amino acid sequence of the peptide is lysine–threonine–threonine–lysine–serine (KTTKS). Sometimes it's also called collagen pentapeptide, as it's a subfragment of skin-structure-giving type I collagen. The KTTKS amino sequence is then attached for better oil solubility and skin penetration to palmitic acid and boom, we get Palmitoyl Pentapeptide-4.
Though most research is manufacturer sponsored, the clinical studies about Palmitoyl Pentapeptide-4 are promising. In short, it can reduce fine lines, wrinkles and improve skin texture significantly (and at crazy low concentrations - the studies were done with just 3 ppm, that is 0.0003%).
There are also studies comparing Palmitoyl Pentapeptide-4 with anti-aging gold standard, retinol. One of hem compared 3ppm Pal-KTTKS with 700 ppm (0.07%) retinol and found that they showed similar wrinkle improving ability with the peptide showing better skin tolerability.
All in all, if you are into peptides, this is a good one to try.
- International Journal of Cosmetic Science, Dec 1, 2011, Topically applied KTTKS: a review