Does raising NAD+ reverse aging in people?

Why NAD+ became an anti-aging target

NAD+ is a coenzyme involved in cellular metabolism, mitochondrial function and DNA repair. Interest grew after animal studies linked falling NAD+ to aging. A 2026 systematic review of 80 rodent studies found that raising NAD+ was often associated with better metabolic, mitochondrial, inflammatory and functional results, although the effects varied between models.

The human starting point is less clear. A 2026 review of intravenous NAD+ noted that recent large human datasets suggest whole-blood NAD+ levels do not decline with healthy aging as such. That does not rule out benefits, but it weakens the simple idea that aging is caused by running low on NAD+ and can be fixed by topping it up.

Sources: PubMed 41655607 · PubMed 42787547

The part that holds up: precursors raise NAD+

Several placebo-controlled trials show that oral precursors increase NAD+. In a 2018 crossover trial in healthy middle-aged and older adults, six weeks of NR was well tolerated and boosted NAD+ metabolism. In a 2019 trial in 12 older men, three weeks of NR raised NAD+-related molecules in muscle and lowered some inflammatory signals in the blood, but it did not change how well the muscle mitochondria produced energy.

NMN behaves similarly. In a 60-day trial in 80 healthy middle-aged adults, blood NAD levels rose in every NMN group. In a 2024 pilot trial in 20 older adults with mild cognitive impairment, NR raised blood NAD+ about 2.6-fold. So the first step of the claim, that you can raise NAD+, is well supported.

Sources: PubMed 29599478 · PubMed 31412242 · PubMed 36482258 · PubMed 37994989

Metabolism and muscle: mostly no clear benefit

When trials looked at metabolism, results were mixed. In a 12-week trial in 40 obese, insulin-resistant men, NR did not improve insulin sensitivity, glucose handling, energy expenditure or body composition. In contrast, a 10-week trial in postmenopausal women with prediabetes who were overweight or obese found that NMN improved insulin sensitivity in muscle. The 2019 trial in older men found no change in muscle energy production.

For muscle and physical function in older adults, a 2025 meta-analysis of randomized trials found that NMN had no significant effect on muscle mass, grip strength or walking speed. The authors concluded that current evidence does not support NMN or NR for preserving muscle mass and function in people over 60.

Sources: PubMed 29992272 · PubMed 33888596 · PubMed 31412242 · PubMed 40275690

Some signals in specific diseases

A few disease-focused trials have reported encouraging but early results. In 90 people with peripheral artery disease, six months of NR improved six-minute walking distance compared with placebo, and the authors called for a larger trial to confirm it. In 30 people newly diagnosed with Parkinson's disease, a month of NR raised brain NAD levels on average, and those whose brain levels rose showed changes in brain metabolism and mild clinical improvement.

Other results were neutral. In the trial of older adults with mild cognitive impairment, NR did not change cognition over 10 weeks, and a reduction in brain blood flow would not have stayed statistically significant after correcting for multiple comparisons. Treating a specific disease is also a different goal from reversing aging in healthy people.

Sources: PubMed 38871717 · PubMed 35235774 · PubMed 37994989

Be careful with "biological age" results

Some trials report a younger "biological age". In the 60-day NMN trial, a blood-based age score rose in the placebo group but stayed stable in the NMN groups, and six-minute walking distance and self-rated health improved. Three of the authors were employees of chemical and pharmaceutical companies (Abinopharm and Aba Chemicals). In the cognitive impairment trial, an exploratory analysis found a modest drop in epigenetic age measures with NR.

Age scores like these are statistical estimates built from blood tests or DNA markers. They have not been shown to predict how changes caused by a supplement affect how long or how well people live. The 2026 systematic review, which covered 33 human intervention studies, found that effects on functional, metabolic, vascular and other healthspan outcomes were mixed and often null, even though NAD+ levels reliably rose.

Sources: PubMed 36482258 · PubMed 37994989 · PubMed 41655607

Intravenous and injected NAD+: very little evidence

IV NAD+ drips are widely sold in wellness clinics, but the evidence for them is much thinner than for oral precursors. The 2026 systematic review found no eligible outcome trials of intravenous or intramuscular NAD+ for anti-aging or wellness, only a small pharmacokinetic pilot. A separate 2026 review concluded that human evidence for IV NAD+ consists mainly of small uncontrolled studies and case reports, with reported side effects including nausea, cramping, flushing and chest discomfort, and no long-term safety data.

A 2026 retrospective review of records from a commercial wellness provider, written by the company's employees, compared IV NAD+ with IV NR. People receiving IV NAD+ reported moderate to severe stomach symptoms, a faster heart rate and chest pressure during infusions, which made infusions much longer. The study had no placebo group and was not designed to test any anti-aging effect.

Sources: PubMed 41655607 · PubMed 42787547 · PubMed 41704678

Profiles

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References

1. NAD⁺ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence. Ageing Res Rev · 2026 · PMID 41655607
2. Narrative review of intravenous NAD(+) and NAD(+) precursors in wellness and translational medicine. Front Aging · 2026 · PMID 42787547
3. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD(+) in healthy middle-aged and older adults. Nat Commun · 2018 · PMID 29599478
4. Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD(+) Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures. Cell Rep · 2019 · PMID 31412242
5. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. Geroscience · 2023 · PMID 36482258
6. A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment. Geroscience · 2024 · PMID 37994989
7. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. Am J Clin Nutr · 2018 · PMID 29992272
8. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science · 2021 · PMID 33888596
9. The Effect of Nicotinamide Mononucleotide and Riboside on Skeletal Muscle Mass and Function: A Systematic Review and Meta-Analysis. J Cachexia Sarcopenia Muscle · 2025 · PMID 40275690
10. Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial. Nat Commun · 2024 · PMID 38871717
11. The NADPARK study: A randomized phase I trial of nicotinamide riboside supplementation in Parkinson's disease. Cell Metab · 2022 · PMID 35235774
12. Intravenous infusion of nicotinamide adenine dinucleotide (NAD(+)) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting. Front Aging · 2026 · PMID 41704678

These are original summaries of published research, written with AI assistance and checked against the cited sources. They are not medical advice and have not been reviewed by a clinician. Every PubMed reference was checked against PubMed's record for title, year and journal. All claim checks · Editorial standards