At a glance: NAD+ is a coenzyme (not a peptide) found in every cell. It is essential for turning food into energy and for DNA repair. Levels tend to fall with age in many tissues. Oral precursors such as NR and NMN reliably raise blood NAD+ in small trials, but health benefits so far are modest and inconsistent. A 2026 systematic review found no controlled trials of NAD+ IV drips or injections for anti-aging or wellness. No NAD+ injection is FDA-approved, and FDA has warned about contaminated compounded products.
What is NAD+?
NAD stands for nicotinamide adenine dinucleotide. It is a small molecule, built from vitamin B3 (niacin) and adenine, that exists in two forms: NAD+, which picks up electrons, and NADH, which carries them. Cells constantly cycle between the two to move energy through their chemical reactions.
The body makes NAD+ from vitamin B3 (niacin, nicotinamide and related forms) and the amino acid tryptophan, and recycles much of it. Food does not contain meaningful amounts of NAD+ itself; B3 comes from foods such as poultry, beef, fish, whole grains, legumes and nuts.
How does NAD+ work?
- Energy production: in the mitochondria, NAD+ and NADH shuttle electrons that cells use to make ATP, their energy currency
- DNA repair: enzymes called PARPs use NAD+ as fuel to fix damaged DNA
- Sirtuins: a family of enzymes linked to metabolism and aging in lab studies needs NAD+ to work
- Breakdown: an enzyme called CD38, which rises with age and inflammation, consumes NAD+, one proposed reason levels fall
Lower NAD+ has been linked in research to metabolic disease, muscle weakness, heart and eye problems and cognitive decline, but these are associations. Researchers are still working out whether low NAD+ causes these problems. A 2026 human study even found that NAD+ measured in blood did not consistently fall with age.
Ways people try to raise NAD+
| Approach | What it is | Evidence |
|---|---|---|
| Niacin / nicotinamide | Classic vitamin B3 forms | Well studied as vitamins; high doses can cause flushing (niacin), headaches and liver problems |
| Nicotinamide riboside (NR) | Oral B3 form sold as a supplement | Raises blood NAD+ in human trials; benefits mixed |
| Nicotinamide mononucleotide (NMN) | Oral precursor one step from NAD+ | Raises blood NAD+ in about 10 small published trials; benefits mixed |
| NAD+ IV drips and injections | Compounded NAD+ given by vein or under the skin | No controlled outcome trials; small pilot studies only |
| Lifestyle | Exercise, sleep, limiting alcohol | Supports overall metabolic health; effect on NAD+ itself is uncertain |
What the research shows so far
| Study | Who was studied | Main finding |
|---|---|---|
| Martens et al., 2018 (NR) | Healthy middle-aged and older adults, 6 weeks | Raised NAD+; blood pressure and artery stiffness trended better in those with higher baseline values, but not significantly |
| Yoshino et al., Science 2021 (NMN) | 25 postmenopausal women with prediabetes, 10 weeks | Improved muscle insulin sensitivity, though NAD+ did not rise in muscle |
| NMN trials review (Song et al., 2023) | 10 published trials, mostly small and short | Raised blood NAD+ about 1.7 to 2.6 times; some signals for muscle strength and walking; "too early" to judge anti-aging effects |
| NICE trial, 2024 (NR) | Adults with peripheral artery disease | Six-minute walk distance improved slightly vs placebo |
| Grant et al., 2019 (IV NAD+) | 11 healthy men; 750 mg over 6 hours vs saline | Blood NAD+ rose only late in the infusion, about 4-fold by 6 hours, with breakdown products rising alongside |
| Gallagher and Emmanuel, 2026 systematic review | 113 studies (33 human, 80 rodent) | Oral boosters well tolerated short term, benefits "inconclusive"; no controlled outcome trials of IV, IM or SC NAD+ |
Several IV NAD+ studies were funded by or run at companies selling NAD+ therapy.
Why it gets attention
- Longevity and anti-aging: mouse studies where restoring NAD+ improved metabolism, muscle and other age-related changes
- Energy and recovery: IV drips are marketed for fatigue, focus, hangovers and athletic recovery
- Addiction recovery claims: some clinics promote NAD+ drips for withdrawal, a use without controlled trial support
- Celebrity and wellness-clinic marketing, plus a booming supplement market for NR and NMN
How it is used
NR and NMN are sold as oral supplements. NAD+ itself is offered as compounded IV infusions, intramuscular shots, under-the-skin injections and nasal sprays, typically at wellness clinics. NAD+ is a large molecule that is quickly broken down outside cells, so how much reaches tissues intact is unclear. No route has an established dose for anti-aging use. This page does not provide dosing guidance.
What about side effects?
Oral NR and NMN have been well tolerated in short trials of a few weeks to months, with no clear pattern of side effects. Long-term safety is not known. IV NAD+ is a different story:
- Infusion reactions: in a 2026 clinic study, all six people given IV NAD+ reported moderate to severe symptoms during the drip, such as cramping, nausea, vomiting, diarrhea, fast heartbeat and chest pressure. Symptoms stopped when the infusion ended, which is why drips are often run slowly over hours.
- Contamination: in 2024 FDA warned that some compounders were using food-grade NAD+ to make IV products, and reported patients needing treatment for severe chills, shaking and vomiting consistent with endotoxin contamination. A compounded NAD+ injection was recalled in 2025 (FDA Class I, its most serious level) for high endotoxin levels.
- Cancer questions: some lab and animal studies suggest boosting NAD+ could help existing cancer cells grow. This has not been shown in people, but long-term data are lacking.
- High-dose niacin or nicotinamide can cause flushing, headaches and liver problems.
- Pregnancy and breastfeeding: NR, NMN and NAD+ injections have not been studied.
Regulatory status
- No FDA-approved NAD+ drug exists for any use. IV and injectable NAD+ is made by compounding pharmacies, under lighter oversight than approved drugs.
- FDA's October 2024 alert told compounders to use only ingredients suitable for sterile products after receiving adverse event reports.
- NR and NMN are sold as dietary supplements, which FDA does not review for effectiveness before sale.
- Niacin itself is an approved vitamin and prescription drug for other uses, which is separate from anti-aging NAD+ products.
The bottom line
NAD+ is genuinely central to how cells make energy and repair DNA, and that biology makes it an appealing anti-aging target. Oral precursors raise blood NAD+ and appear safe in the short term, but proof that they make people healthier or slow aging is still thin. IV and injectable NAD+ has even less support: no controlled outcome trials, frequent unpleasant infusion reactions and documented contamination problems. Eating enough B3, exercising and sleeping well remain the evidence-based basics. Anyone considering NAD+ therapy should talk with a clinician first.
Frequently asked questions
What is NAD+?
A coenzyme found in every cell that is central to energy metabolism. It is not a peptide, but it is often sold alongside them.
How is NAD+ taken?
Oral precursors, intravenous infusion.
Is NAD+ FDA approved?
Precursors are sold as supplements; not approved as a drug.
That means no regulator has reviewed its safety, effectiveness or manufacturing quality for this use.
What has research shown about NAD+?
- How NAD+ levels decline with age, in animal studies.
- Raising NAD+ with precursors such as NR and NMN, in human trials.
- IV NAD+, which has little controlled research.
What side effects have been reported?
- Oral precursors: nausea, headache
- IV infusion: flushing, chest tightness, nausea if infused quickly
Serious or less common risks are listed in the Side Effects section above.
What is still unknown about its safety?
Most of it. NAD+ has not been through the trials that establish long-term safety in people, and products sold online are made by unregulated labs. Independent testing of online peptides has repeatedly found contents that do not match the label.
References
- Cleveland Clinic: NAD (nicotinamide adenine dinucleotide). View source
- Song Q, et al. The safety and antiaging effects of nicotinamide mononucleotide in human clinical trials: an update. Advances in Nutrition. 2023. View source
- Grant R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Frontiers in Aging Neuroscience. 2019. View source
- Reyna K, et al. Intravenous infusion of NAD+ versus nicotinamide riboside: a retrospective tolerability pilot study. Frontiers in Aging. 2026. View source
- FDA: FDA reminds compounders to use ingredients suitable for sterile compounding (October 2024). View source
- HMP Global: FDA issues Class I recall of NAD+ injection due to elevated endotoxin levels (2025). View source
- Science-Based Medicine: Science vs hype, the unproven promise of NAD+ IV therapy (2026). View source
- MedShadow: NAD+ supplements, do they work? (review of NR and NMN trials, 2026 systematic review). View source