Nicotinamide in dermatology and photoprotection.

Nicotinamide (the amide form of vitamin B3) has been used in dermatology for more than 40 years for a diverse range of conditions including acne, rosacea, autoimmune bullous dermatoses, and now the treatment and prevention of photoaging and photoimmunosuppression. The broad clinical effects of nicotinamide may be explained by its role as a cellular energy precursor, a modulator of inflammatory cytokines, and an inhibitor of the nuclear enzyme poly(adenosine diphosphate-ribose) polymerase-1, which plays a significant role in DNA repair, maintenance ofgenomic stability, and cellular response to injury including inflammation and apoptosis. This review outlines the use of nicotinamide for inflammatory dermatoses and photoaging and focuses on its emerging role in photoprotection.