Abstract
Vitamin D is a natural photoproduct that has many beneficial effects on different organs, including skin. Active forms of vitamin D and its derivatives exert biological effects on skin cells, thus maintaining skin homeostasis. In keratinocytes, they inhibit proliferation and stimulate differentiation, have anti-inflammatory properties, act as antioxidants, inhibit DNA damage and stimulate DNA repair after ultraviolet (UV) exposure. In melanocytes, they also inhibit cell proliferation, inhibit apoptosis and act as antioxidants. In fibroblasts, they inhibit cell proliferation, affect fibrotic processes and collagen production, and promote wound healing and regeneration. On the other hand, skin cells have the ability to activate vitamin D directly. These activities, along with the projected topical application of vitamin D derivatives, are promising for skin care and photo protection and can be used in the prevention or possible reversal of skin aging.