Cofactor
Throughout life, the skin is exposed to a number of factors which may affect its structure, function, and appearance. The aging process contributes to the loss of elasticity and to wrinkle formation, as well as solar radiation. Effects resulting in pigmentation and accelerating wrinkle formation are the main internal and external factors affecting the appearance of the skin. UV radiation reduces the content of vitamin C in the dermis which prevents peroxidation of lipids (fats) and protects keratinocytes from apoptosis (cell death). Vitamin C aids the formation of the top layer of the epidermis and consequently protects the skin from loss of water and drying.The optimum vitamin C concentration, which is beneficial to skin health and serve as protection against age-related changes, is not yet clear.