An amide form of niacin; precursor in the synthesis of the metabolic cofactor NAD+; an inhibitor of SIRT1 (IC50 = <50 µM); increases SPT activity and the biosynthesis of ceramide glucosylceramide, sphingomyelin, free fatty acids, and cholesterol in primary human keratinocytes at 10 µM; induces apoptosis in SNU-398, SNU-739, and HepG2 cells at 40 µM; prevents the formation of neoplastic lesions in a diethylnitrosamine-induced mouse model of HCC