Enzymes break down the keratin protein that acts as glue between the layer of dead cells found in our epidermis. 

This layer is responsible for the lack of luminosity and for the fact that our tone is not uniform, that it looks grayish and dull. In other words, papaya enzymes become an exfoliant that helps to remove dead skin, just as alpha hydroxy acids do, although the tolerance of papain is much better. Among its benefits is also the stimulation of collagen production.