Papain is an enzyme derived from pineapple and papaya fruits. It has many topical uses including wound debridement and face creams.
Papain's protease activity is also used to tenderize meat.
Papain is a sulfhydryl protease enzyme derived from pineapples and papayas (Carica papaya). Papain is used in a wide variety of enzymatic formulations, and as a digestive aid is sometimes called "vegetable pepsin".
As any enzyme, papain is often expressed in units of activity. Common unit types include: FCC or N.F. units, milk-clotting units (MCU), gelatin-digestion units (GDU) or casein digestion units (CDU). Papain is listed in both the N.F. and U.S.P.
Severe irritation to the skin is not uncommon when used topically.