NAD+
Also called: nicotinamide adenine dinucleotide
Clinical reviewer: Jacob Moore, MD · Last checked September 16, 2026
What is NAD+?
NAD+ is a coenzyme found in every cell that helps transfer energy from food into a usable form, and is chemically a dinucleotide rather than a peptide. More than 400 enzymes require it for energy metabolism and DNA maintenance. NAD+ is reported to decline with age in animals and humans, though reviewers disagree on how consistent that decline is.
What does NAD+ do in the body?
NAD+ is the main active coenzyme form of niacin; the NIH's Office of Dietary Supplements says more than 400 enzymes require it, more than for any other vitamin-derived coenzyme [1]. It mainly moves energy from carbohydrates, fats and protein into ATP, and separately supports enzymes that maintain genome integrity and control gene expression [1]. It is a small dinucleotide molecule, not an amino-acid chain, so it is not a peptide.
Does NAD+ decline with age?
The evidence is mixed. A 2021 review in Nature Reviews Molecular Cell Biology reports a gradual decline in tissue NAD+ with age in rodents and humans, but says it remains unclear how to safely restore it or whether doing so helps ageing humans [2]. A separate 2021 review in Nutrients concluded the evidence for an overall age-related decline is very limited and, in humans, still poorly characterized [3]. Neither review addresses injectable NAD+ specifically.
Is NAD+ FDA-approved, and what is its compounding status?
No NAD+ product is FDA-approved; FDA's May 14, 2026 list keeps NAD and NADH in Category 1, meaning compounding is under evaluation rather than authorized outright [4]. That status does not depend on the ageing debate above — it turns on whether a pharmacy meets the section 503A conditions FDA has set. Measured has written more on the evidence behind NAD+ injections.
Related terms
Sources
- NIH Office of Dietary Supplements — Niacin, Health Professional Fact Sheet
- Covarrubias AJ et al. NAD+ metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol, 2021.
- Peluso A et al. Age-Dependent Decline of NAD+ — Universal Truth or Confounded Consensus? Nutrients, 2021.
- FDA — Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (Updated May 14, 2026)
This entry is for education and is not medical advice. Talk with a licensed clinician about your own situation before starting, stopping, or changing any treatment.
