What is the lifespan of an epidermal cell?

The lifespan of an epidermal cell, specifically keratinocytes in the outer layer of the skin, generally ranges from about 28 to 30 days. These cells continuously renew through a process of division in the deeper layers of the epidermis, gradually moving up to the surface where they eventually die and are shed off. Factors such as age, skin health, and environmental exposure can influence this lifespan.