The primary role of exogenous peptides is to effect changes in the complex pathways regulating the expression of skin proteins, generally to prevent signs of ageing. In other words, peptides are most often used to trigger a signalling cascade and stimulate the production of collagen and elastin. These fibrous proteins present in the dermis ensure flexibility and firmness to the skin, but their content in the skin tends to decrease over the years. Moreover, certain peptides can also boost the production of hyaluronic acid in the skin, for a hydrated, plump and smoother skin.
In relation to the I.N.C.I. nomenclature, Greek qualifying prefixes are used. For instance, di-, tri-, tetra-, pentapeptides refer to peptides of 2, 3, 4, and 5 amino acids in length, and so forth. There are numerous variations: tetrapeptide-2, acetyl tetrapeptide-15, hexapeptide-2, acetyl tetrapeptide-9, alanyl glutamine, acetyl hexapeptide-1, carnosine, acetyl tetrapeptide-11, cyclopeptide-5, and so on...
Note : Peptides can have functions beyond their role in reducing the appearance of wrinkles. They can influence various biological processes in the skin such as inflammation, cell proliferation, melanogenesis, oxidative stress... When applied to hair follicles, certain peptides offer densifying properties. They stimulate, strengthen and densify the cells of eyelashes and eyebrows, while helping to keep them healthy.