Nicotinamide riboside (NR) is a form of vitamin B3 found in cow’s milk. Laboratory studies report administration of nicotinamide riboside supports healthy levels of NAD+ in yeast and cultured human and mammalian cells. NR is reported to be incorporated into the cellular NAD+ pool via the action of nicotinamide riboside kinase (Nrk) pathway or via nicotinamide (Nam) salvage after conversion to Nam by phosphorolysis. Laboratory studies have also reported the supportive and neuroprotective role for NAD+. In laboratory studies, nicotinamide riboside supports neuronal NAD+ synthesis without inhibiting sirtuins, which are important regulators of metabolism and longevity.