Plant extract that is the source of the enzyme papain, which theoretically can have exfoliating properties on skin, although the majority of the research was not performed on skin. Papaya can be a skin irritant, but it’s not as potentially risky as pure papain.  Still, it’s not an ingredient to apply daily; there are better options for leave-on exfoliants, including glycolic acid and salicylic acid.
- Murthy M, Murthy B, Bhave S. Comparison of safety and efficacy of papaya dressing with hydrogen peroxide solution on wound bed preparation in patients with wound gape. Indian J Pharmacol. 2012;44(6):784-7.