NAD+

Nicotinamide adenine dinucleotide (NAD+) is a fundamental coenzyme found in all living cells, where it participates as an electron carrier in oxidative phosphorylation and as a substrate for a diverse class of enzymes that regulate metabolism, stress responses, and aging. NAD+ levels decline with age, caloric excess, and various disease states — a decline that has become a major focus of aging biology research over the past decade.

NAD+ serves two distinct biochemical roles. As a redox carrier, NAD+/NADH couples substrate oxidation to the electron transport chain, driving ATP synthesis in mitochondria. As an enzyme substrate (rather than a cofactor), NAD+ is consumed and regenerated in reactions catalyzed by sirtuins (SIRT1-7), PARP enzymes (involved in DNA repair), and CD38 (an NADase involved in calcium signaling). This dual role means that NAD+ depletion impacts both energy production and regulatory signaling simultaneously.

Research on NAD+ supplementation strategies has grown substantially following seminal work by Guarente, Sinclair, and others demonstrating that restoring NAD+ levels in aged animals could reverse multiple age-associated phenotypes. Studies using NAD+ precursors (NMN, NR) or direct NAD+ have documented effects on mitochondrial function, sirtuin activity, PARP-mediated DNA repair, and inflammatory signaling in both cellular and animal models. NAD+ also plays a central role in the biology of circadian rhythms through NAMPT-mediated synthesis regulation.

NAD+ for research is used in cell-free biochemical assays, enzyme activity measurements, and cellular supplementation studies. Investigators working on sirtuins, PARP biology, mitochondrial metabolism, or aging mechanisms will find NAD+ an essential research reagent. Available for laboratory use only.