Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite in energy metabolism as well as a co-substrate in biochemical reactions such as protein deacylation, protein ADP-ribosylation and cyclic ADP-ribose synthesis mediated by sirtuins, poly (ADP-ribose) polymerases (PARPs) and CD38. In eukaryotic cells, NAD+ is synthesized through three distinct pathways, which offer different strategies to modulate the bioavailability of NAD+. The therapeutic potential of dietarily available NAD+ boosters preserving the NAD+ pool has been attracting attention after the discovery of declining NAD+ levels in ageing model organisms as well as in several age-related diseases, including cardiometabolic and neurodegenerative diseases. Here, we review the recent advances in the biology of NAD+, including the salubrious effects of NAD+ boosters and discuss their future translational strategies.