Subtilisin is an enzyme, a serine-protease (protein degrading ferment where serine amino acid is in active site) obtained by microbial fermentation. This enzyme is characterized by very wide substrate specificity and good stability to pH and temperature, so it can catalyze the cleavage of most of the peptide links in a protein, including keratin, reducing it to small peptides easily soluble.
Therefore it can be applied to the skin to carry out a keratolytic action; thus, Subtilisin is an excellent natural substitute for hydroxy acids AHAs, BHAs, and PHAs. Furthermore, comparative tests for keratolytic effect showed that bacterial proteolytic enzyme is effective with mild and non-irritating action, while the AHAs have higher irritating potential. It dissolves "glue" holding keratinocytes on the skin surface, eliminating dull, pigmented, or dead cells from the skin surface, revealing a refreshed, bright, and glowing appearance without irritation or sensitization.
In addition, it can break down peptides produced in the hair follicles, which are building blocks for keratin formation, a primary protein component of hair. So, Subtilisin limits hair growth in undesirable sites, exposing fresher, youthful, and flawless skin.
Subtilisin breaks down keratin until free amino acids that act as NMFs (natural moisturizing factors), providing secondary beneficial effects, improving skin hydration, and lessening transdermal moisture loss. Compared with chemical peeling enzymatic is a more natural way of exfoliation, with no inferior efficiency and better safety, which is getting popular among high-end skin care applications.