Niacin pretreatment of skin cells protects against UV-induced cell death and apoptosis by enhancing the pro-survival pathways including AKT, mTOR and S6 in skin keratinocytes. Oral and external niacin is safe and appears to be a promising chemo-preventive supplement for reducing the mutagenic, immunosuppressive and cell damage effects of sunlight. This is also the first study providing a molecular mechanism to support that niacin can be utilized as a skin photo-damage protective agent.