NAD+

NAD+ is nicotinamide adenine dinucleotide in its oxidized form. It is an endogenous coenzyme found in every living cell, transferring electrons in glycolysis, the citric-acid cycle, and oxidative phosphorylation, and serving as obligate substrate of sirtuins, PARPs, and CD38.

No. NAD+ is a dinucleotide coenzyme — a small organic molecule consisting of two nucleotides (nicotinamide-ribose-phosphate and adenosine-monophosphate) joined by a pyrophosphate bridge. It is included in the PEPPUDEX as a longevity-research reference compound.

NR (nicotinamide riboside) and NMN (nicotinamide mononucleotide) are NAD+ precursors that cross the plasma membrane more efficiently than full NAD+. Most clinical research uses precursors; direct NAD+ administration is debated. The precursors are most relevant for oral supplementation.

CD38 ectoenzyme activity increases with age, hydrolyzing NAD+ on cell surfaces. Increased oxidative stress and PARP activation also consume NAD+. The net result is a documented decline in cellular NAD+ across mammalian tissues with aging (Imai & Guarente, Trends Cell Biol 2014; PMID 24786309).

No. NAD+ is not FDA-approved as a drug. The NAD+ precursors NR and NMN have been the subject of FDA enforcement actions regarding their classification as dietary supplements vs investigational drugs. Exogenous NAD+ salt is sold as a chemistry reagent for laboratory use.

Three distinct roles: (1) electron transfer in dehydrogenase reactions, generating NADH for the electron-transport chain; (2) obligate substrate of class-III lysine deacylases (SIRT1–SIRT7); (3) substrate of poly-ADP-ribose polymerases (PARPs) and CD38 ectoenzymes.

Short — on the order of minutes in plasma. Intracellular pools are cycled continuously through the salvage pathway. Most research interest is therefore in raising intracellular NAD+ via precursors that cross the plasma membrane.

There is no clinical evidence that NAD+ supplementation reverses aging. Precursor trials reliably raise blood NAD+ but show modest and mixed effects on functional aging endpoints (cognition, energy, metabolic markers). The biology is real; the translation is incomplete.

Not currently listed on the WADA Prohibited List as of 2026.

Lyophilized NAD+ is stable at 2–8 °C protected from light for 12+ months. Reconstituted solution should be stored at 2–8 °C protected from light and aliquot-frozen for storage beyond 7 days. Avoid repeat freeze-thaw.

The nicotinamide moiety undergoes photochemical decomposition under UV exposure, producing inactive degradation products. Amber-glass vials or foil-wrapped clear vials are standard practice.