The biological activity of polypeptide depends on its amino acid composition and sequence, and almost all physiological processes in human body are regulated by polypeptide or protein composed of specific amino acid sequence. Therefore, bioactive peptides have become a new direction and new idea in cosmetics research and application, and their functions are increasingly subdivided, such as anti-aging, repair, anti-oxidation, anti-edema, promoting hair regeneration, inhibiting melanin production, breast enhancement, weight loss and so on.

Skin is a natural barrier for human body to resist the invasion of external environment, and it has a certain protective effect on external stimuli, thanks to the protective effect of dense stratum corneum. However, it also prevents the nutrients of cosmetics from entering the skin surface. Nutrition needs to penetrate the cell membrane of stratum corneum to enter the dermis, and only a small amount of macromolecules and fat-soluble substances can be absorbed through pores and sweat pores. Therefore, most of the cosmetics we usually use only stay on the skin surface, and bioactive beauty peptides can easily enter the dermis through the gap between the cuticles, thus playing a role.

Polypeptide was originally used directly in products by some European and American cosmeceuticals, and its mechanism of action is similar to that of protein, which can promote the proliferation of collagen, elastic fiber and hyaluronic acid, increase skin moisture content, increase skin thickness and reduce fine lines. Because of the different kinds of amino acids, they can play different roles and meet the needs of different skin functions.