A riboside form of nicotinamide; a precursor of NAD+ and a source of vitamin B3; increases intracellular and mitochondrial NAD+ content in C2C12, Hepa1.6, and HEK293 cells in a concentration-dependent manner at concentrations ranging from 1-1,000 μM; decreases acetylation of FOXO1 and SOD2 but not tubulin; increases NAD+ levels in liver and skeletal muscle and prevents body weight gain in mice fed a high-fat diet when used at a dose of 400 mg/kg per day; increases NAD+ in the cerebral cortex and reduces cognitive deterioration in a transgenic mouse model of Alzheimer's disease,