Molecule
NAD+
Nicotinamide adenine dinucleotide
A coenzyme every cell uses to convert nutrients into energy. Levels decline with age. Whether raising it matters is the field's most-litigated question.
Summary Can NAD+ supplements really slow ageing or improve health? Show / hide ↓
NAD+ is a helper molecule that every cell uses to turn food into energy and support cell maintenance. NAD+ itself is not practical as an oral supplement because digestion breaks it down, so products usually contain precursors, or starting compounds, such as NR and NMN that the body converts into NAD+. Human studies consistently show that these supplements raise NAD+ levels in the blood. They have not yet produced large improvements in major health outcomes among healthy adults, although some studies suggest benefits in specific groups, including people with high blood pressure or Parkinson’s disease. Typical studied doses of 300–1000 mg per day appear generally well tolerated, but long-term data beyond two years is limited and mild stomach problems have been reported.
What this means for you: NAD+ precursors clearly change a blood measurement, but that is not the same as slowing ageing. Evidence is too limited to recommend them for healthy adults.
moderate evidenceNAD+ sits at the center of the sirtuin longevity thesis. Sirtuins are enzymes that consume NAD+ to remove chemical modifications from proteins, and their activity has been tied to DNA repair, mitochondrial function, and inflammation control. When NAD+ falls, sirtuin activity falls with it. That is the mechanistic story.
The clinical picture is thinner. NAD+ itself is not sold as a supplement in oral form because the intact molecule does not survive digestion. What is sold are precursors, mainly nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), which the body converts back to NAD+. Both raise blood NAD+ levels in humans, consistently. What both fail to do, so far, is produce large effects on hard clinical endpoints in healthy adults.
Where NAD+ boosters have shown the clearest human signal is in specific patient groups: elevated blood pressure in some trials, cardiovascular markers in Parkinson's, mild muscle biomarker changes in older adults. The signal in healthy people who already have functional NAD+ metabolism is much smaller. This is the honest version.
CD38 is worth a mention. CD38 is an enzyme that consumes NAD+ and rises with age, which is one reason NAD+ falls. Apigenin and quercetin inhibit CD38 in animal work, which is why some longevity stacks pair NAD+ precursors with a CD38 inhibitor. Human evidence for this pairing is still preclinical.
Safety-wise, both NR and NMN look benign at typical doses (300-1000 mg/day). Long-term data past two years is limited. Some trials have flagged mild GI effects.
Further reading
Curated external sources for a deeper dive. External links open in a new tab.
- NAD+ in Aging, Metabolism, and Neurodegeneration (Verdin, Science 2015) Science
- Nicotinamide riboside and nicotinamide mononucleotide: are they the same thing? (Trammell 2016) PubMed
- Charles Brenner on NMN vs NR (Twitter thread archive) Charles Brenner
- Rejuvenation Now: NAD+ (Peter Attia podcast) Peter Attia MD