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NAD+ precursors (NMN, NR)

Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are forms of vitamin B3 sold as supplements to raise NAD+, a coenzyme whose levels are thought to fall with age. Randomised trials consistently show that both raise NAD+ and related metabolites in blood and are well tolerated over weeks to months. Meta-analyses of these mostly small, short trials in adults have not found consistent benefits for blood sugar, insulin sensitivity, blood lipids, body weight or muscle mass and function, and no human trial has measured an effect on lifespan or healthspan. Long-term safety has not been established.

  • Energy
  • Longevity

Evidence retrieved up to

What the research shows

In randomised trials in adults, oral nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) consistently raise NAD+ and related metabolites in blood. This is a biochemical change; on its own it does not show a health benefit.

Moderate certaintyFurther research may change the size of the effect.
No known concerns at usual amountsUnclear

Who this is about

adults, mostly healthy middle-aged and older adults, in randomised trials

Practical note

Graded moderate: a 2026 systematic review of 33 human studies (28 randomised) found consistent rises in blood NAD-related metabolites, supported by individual trials such as a 2018 crossover trial of NR; downgraded one level because the trials are small and short. Direction is set to unclear because a rise in a blood marker is not a demonstrated health outcome.

Vegan note

The sources say nothing about vegan status. A 2023 review lists chemical synthesis, microbial fermentation and enzymatic synthesis as production methods for NMN; capsule materials and other ingredients were not covered.

Sources

In meta-analyses of short randomised trials in mostly healthy middle-aged and older adults, NMN did not consistently improve fasting glucose, insulin sensitivity markers, HbA1c, blood lipids, body weight or BMI compared with placebo.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsNo clear effect

Who this is about

mostly healthy middle-aged and older adults

Practical note

Graded low: two meta-analyses of randomised trials agree, but the trials are few, small (8 trials and 342 participants in the 2024 analysis) and short (14 days to 24 weeks), so the evidence is imprecise. The 2026 meta-analysis reported a slight fall in diastolic blood pressure and a non-significant downward trend in an insulin resistance index, which its authors call preliminary signals.

Sources

In randomised trials in adults over 60, NMN and NR did not improve muscle mass, grip strength, gait speed or other measures of physical performance compared with placebo.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsNo clear effect

Who this is about

adults with a mean age over 60

Practical note

Graded low: a 2025 meta-analysis of randomised trials found no effect on muscle mass, grip strength, gait speed or chair-stand time, but each pooled analysis included only 2 to 5 trials and some outcomes could only be summarised narratively. A 2026 systematic review of 33 human studies likewise found functional and healthspan-relevant outcomes heterogeneous and often null.

Sources

In randomised trials lasting from two weeks to about six months, oral NMN and NR were well tolerated in adults, and NMN did not increase adverse events or liver enzymes compared with control; safety over longer periods has not been established.

Moderate certaintyFurther research may change the size of the effect.
Take care: see the safety noteNo clear effect

Who this is about

adults in short-term randomised trials

Practical note

Graded moderate: a 2026 meta-analysis of randomised trials (10 trials in the safety analyses) and a 2026 systematic review of 33 human studies agree that short-term use was well tolerated; downgraded for imprecision, since the trials are small and too short to detect rare or delayed harms.

Safety note

The evidence covers weeks to months only; reviewers call for larger and longer trials to confirm long-term safety.

Sources

No human trial has shown that NMN or NR extends lifespan or healthspan; a 2026 systematic review judged their effectiveness for anti-ageing outcomes inconclusive, and in a large mouse lifespan study NR did not extend lifespan.

Very low certaintyThis is uncertain; treat it as a lead, not a finding.
No known concerns at usual amountsUnclear

Who this is about

adults, including older adults

Practical note

Graded very low: there is no direct human evidence on lifespan, the human trials measure short-term markers rather than ageing outcomes, and the lifespan evidence that exists is from animals.

Sources