Trade name Matrixyl, a fatty acid mixed with amino acids. Manufactured by the French lab Sederma, it is used primarily as an ingredient in cosmetics making anti-wrinkle claims. Studies both from Sederma and from independent researchers have shown palmitoyl pentapeptide-4 can have an impact on the visual signs of aging, including fine lines and wrinkles.
References for this information:
Molecular Pharmaceutics, March 2013, pages 1,063-1,069
Clinica in Plastic Surgery, July 2011, pages 397-407
International Journal of Cosmetic Science, June 2005, pages 155-160