NAD+ (nicotinamide adenine dinucleotide, oxidized form) is a pyridine dinucleotide coenzyme ubiquitous in all living organisms, first identified by Arthur Harden and William John Young in 1906 during studies of yeast fermentation and structurally elucidated by Hans von Euler-Chelpin — work recognized by the 1929 Nobel Prize in Chemistry. The molecule cycles between its oxidized (NAD+) and reduced (NADH) states, serving as the primary hydride-accepting electron carrier in the citric acid cycle and mitochondrial oxidative phosphorylation.

Research over the past two decades has established NAD+ as the obligate co-substrate for three distinct enzyme superfamilies: sirtuins (SIRT1–7, NAD+-dependent protein deacylases), poly(ADP-ribose) polymerases (PARPs, DNA damage sensors), and cyclic ADP-ribose synthases (CD38, CD157). Work from David Sinclair’s laboratory at Harvard Medical School and Johan Auwerx’s group at EPFL has focused on the consequences of age-related NAD+ depletion for mitochondrial biogenesis, electron transport chain function, and genomic stability in rodent models. Charles Brenner at the University of Iowa characterized the nicotinamide riboside (NR) and NMN salvage biosynthesis pathways as routes to replenish cellular NAD+ pools. All findings referenced here derive from preclinical or early-phase research models and have not been validated in controlled human clinical trials.

NAD+ research appears in Cell Metabolism, Nature, Science, and PNAS. It is not approved by the U.S. Food and Drug Administration for any diagnostic, therapeutic, or preventive application. It is classified as a research compound only.