The short answer: Not on current evidence. Human trials show that nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) raise NAD+ in blood and are well tolerated for weeks to months. No human trial has shown that they extend life or prevent age-related disease. For NAD+ infusions, a 2026 systematic review found no outcome trials at all for anti-aging or wellness use.

What is NAD+ and why do people take precursors?

NAD+ (nicotinamide adenine dinucleotide) is a molecule made from vitamin B3. Cells use it in energy metabolism and in enzymes that repair DNA. A 2026 systematic review in Ageing Research Reviews notes that NAD+ declines with age. That decline is the reason for "NAD+ boosting".

The supplements do not contain NAD+ itself. They contain precursors, the building blocks that the body converts to NAD+. The two main ones are NR and NMN. Some clinics also sell NAD+ given through a vein.

The claim has two steps. Step one: the supplement raises NAD+. Step two: higher NAD+ slows aging. Human trials support step one. Step two is where the evidence stops.

What does the animal evidence show?

Most of the excitement comes from mice. In a 12-month mouse study in Cell Metabolism, NMN suppressed age-related weight gain, improved insulin sensitivity, and increased physical activity. The authors reported no obvious toxicity.

Lifespan is a different question. A 2021 lifespan study in Aging Cell tested NR in genetically mixed male and female mice. NR did not significantly increase lifespan at the doses tested.

These are animal results. A healthier old mouse does not show that a person will live longer. Only human trials can answer that.

Do NR and NMN raise NAD+ in people?

Yes. This is the most consistent human finding.

The same 2026 study suggests that gut bacteria convert NR and NMN to nicotinic acid, an older form of vitamin B3. The authors propose that this conversion explains part of the NAD+ rise. The open-label design and the authors' employment at Nestlé are reasons to wait for confirmation.

A higher blood level is a laboratory result. It is not a health outcome.

Do they improve health outcomes in human trials?

Results are mixed, and most are null. The 2026 systematic review counted 33 human intervention studies, 28 of them randomized. It found that effects on functional, metabolic, and vascular outcomes were "heterogeneous and often null or endpoint-specific".

Metabolism. A Danish trial in the American Journal of Clinical Nutrition gave 40 obese, insulin-resistant men 1,000 mg of NR twice a day for 12 weeks. Insulin sensitivity, energy expenditure, and body composition did not change. A 10-week trial in Science found that NMN increased muscle insulin sensitivity in postmenopausal women with prediabetes. A 2026 meta-analysis of 15 NMN trials found no significant effect on body weight, fasting glucose, HbA1c, lipids, or systolic blood pressure. Diastolic blood pressure fell slightly.

Muscle and physical function. A 2025 meta-analysis in the Journal of Cachexia, Sarcopenia and Muscle pooled trials in adults with a mean age above 60. NMN had no significant effect on muscle mass, handgrip strength, or gait speed. The authors concluded that current evidence does not support NMN or NR for preserving muscle mass and function. Resistance training is the better-tested approach, as our articles on how fast you lose muscle and creatine for older adults explain.

Walking in artery disease. The NICE trial studied 90 people with peripheral artery disease for 6 months. NR improved 6-minute walk distance by 17.6 meters compared with placebo. The authors said a larger trial is needed to confirm the result.

Cognition. A pilot trial in 20 older adults with mild cognitive impairment used NR at up to 1 g a day for 10 weeks. Blood NAD+ rose 2.6-fold. Cognition did not change.

Three limits apply to all of these trials:

  • They are small. The largest single trial above enrolled 90 people.
  • They are short. The longest one above ran 6 months. The NMN trials in the 2026 meta-analysis ran 14 days to 24 weeks.
  • They measure markers. None of them measured lifespan or the onset of age-related disease.

Industry ties also appear. Three authors of the 80-person NMN trial were company employees, and the NR cognition trial lists a co-author who owns stock in the NR supplier.

Do NAD+ infusions work better than pills?

There is no trial evidence that they do. The 2026 systematic review found no eligible outcome trials of intravenous or intramuscular NAD+ for anti-aging or wellness.

The human data are thin. A 2019 pilot study tracked NAD+ in plasma and urine during a 6-hour infusion. It measured where the NAD+ went. It did not measure any health benefit.

A 2026 retrospective study reviewed the records of clinic clients who received NAD+ or NR by vein on four consecutive days. People who received NAD+ reported moderate to severe gastrointestinal symptoms, increased heart rate, and chest pressure during the infusions. Symptoms resolved when the infusion ended. NAD+ infusions averaged 97 minutes, against 37 minutes for NR. All of the authors were employed by a commercial wellness company.

Are NAD+ supplements safe, and what is their FDA status?

Short-term safety looks acceptable. The 2026 NMN meta-analysis covered doses of 250 to 2,000 mg a day. NMN did not increase adverse events, serious adverse events, or liver enzymes. Long-term safety is unknown, because no trial in that analysis lasted longer than 24 weeks.

The legal status of NMN in the United States changed twice. An FDA citizen petition response signed on September 29, 2025 gives the history:

  1. On October 11, 2022, the FDA told a manufacturer that NMN was excluded from the definition of a dietary supplement. The reason was that NMN had been authorized for investigation as a new drug.
  2. In the 2025 response, the FDA reversed that position. It concluded that NMN "is not excluded from the definition of dietary supplement". The agency cited evidence that NMN was sold as a supplement in the United States as early as 2017, before the drug investigation was authorized.

That decision is about legal category. It is not a finding that NMN works. The same letter states that when the FDA accepts a new dietary ingredient notification, the acceptance is not a finding that the ingredient is safe. Our sister site supplements.md reviews the evidence for other supplements.

The bottom line

NR and NMN raise NAD+ in blood. That part of the claim is correct. No human trial shows that they slow aging, prevent disease, or extend life, and pooled analyses find little or no effect on muscle, glucose, or lipids. NAD+ infusions have even less evidence and more reported side effects during treatment.

The habits with the strongest human data are not sold in a capsule. Our review of longevity habits and their evidence covers the options with better support. If you still want to try a precursor, tell your doctor, mainly if you take prescription medication or have a chronic condition.

Last updated: October 2026. This article is for informational purposes only and does not constitute medical advice. Talk with your doctor or pharmacist before you start NR, NMN, an NAD+ infusion, or any other supplement.