Does NMN Improve Energy, Exercise, and Recovery? What the Human Trials Actually Show

NMN (nicotinamide mononucleotide) is a precursor of NAD+, the coenzyme your cells use for energy. The most consistent finding in people is that it raises blood NAD+ levels (Gallagher 2026). Most of what else you hear about it, such as more energy, better lifts, faster recovery and slower aging, is far less certain. In pooled trials, endurance improved at medium and high doses, while strength, fatigue and sleep did not (Gao 2026); muscle mass did not change in older adults (Prokopidis 2025); and in one runner trial VO2max did not move (Liao 2021). The strongest “anti-aging” signals come from rodents (Gallagher 2026). Here is what the human evidence shows.

The most reliable effect: blood NAD+

NMN consistently raises circulating NAD+. In a randomized trial of 80 healthy middle-aged adults over 60 days, every dose from 300 to 900 mg/day did (Yi 2023). So did a 28-day randomized trial in 30 overweight or obese adults aged 45 and over, who took two 500 mg tablets twice daily, or 2,000 mg/day (Pencina 2023). The target is engaged. Whether a higher NAD+ number changes how you feel or perform is the open question, and on that the evidence is mixed.

Endurance: the clearest signal, at medium and high doses

Endurance is NMN’s clearest performance signal. A 2026 network meta-analysis of 27 studies (1,599 adults) pooled several NAD+ precursors. In it, NMN improved endurance at a medium dose (SMD 0.66) and more at a high dose (SMD 1.02), while strength did not change and no precursor improved perceived fatigue or sleep (Gao 2026). In a 6-week randomized trial of 48 recreational runners who were also training, 600 and 1,200 mg/day raised power at the ventilatory thresholds compared with placebo, but VO2max and peak power did not change (Liao 2021). In that trial, the gains were in sub-maximal measures, not peak capacity.

Strength and muscle: the claims that don’t hold up

“Better lifts and less muscle loss” are among the least-supported claims. A 2025 meta-analysis of randomized trials in adults with a mean age over 60 found NMN had no significant effect on muscle index, grip, gait speed or chair stands: “current evidence does not support NMN and NR supplementation for preserving muscle mass and function” (Prokopidis 2025). A 24-week randomized trial of 14 older men with diabetes and impaired physical performance found no grip or walking-speed gain over placebo (Akasaka 2023). A wrinkle: a second 2025 meta-analysis, of 9 trials in 412 middle-aged and older adults, did find a modest gait-speed gain (Wang 2025). When two reviews of one endpoint disagree, the evidence base is thin, not settled.

A timing detail, with a caveat

In a randomized trial of 108 older Japanese adults taking 250 mg/day or placebo for 12 weeks, all four groups, placebo included, improved on the 5× sit-to-stand test. The afternoon NMN group showed the largest within-group effects, for sit-to-stand (d=0.72) and drowsiness (d=0.64), and the authors concluded that afternoon intake improved lower-limb function (Kim 2022). Because the placebo groups also improved, treat the timing result as a lead, not a finding.

Recovery: a small new trial raises a flag

In a 2026 crossover trial, 11 untrained men took 1,200 mg/day of NMN or placebo for 7 days before blood-flow-restriction resistance exercise. NMN suppressed inflammatory signaling in muscle and delayed a marker of muscle differentiation. Exercise raised muscle mitochondrial content by 171% after 24 hours, and NMN abolished that rise. The authors suggest NMN may suppress the transfer of mitochondria from immune cells to repairing muscle fibers (Yang 2026). Read one way, NMN may quiet part of the repair process. It’s a small study: a flag, not a verdict.

The honest alternative: exercise raises the enzyme for free

You don’t need a capsule to touch the NAD+ pathway. A meta-analysis of five studies found exercise training raised intracellular NAMPT, the rate-limiting NAD+ enzyme, in skeletal muscle by about 1.46-fold, supplement-free (Sun 2023). On metabolic markers, a meta-analysis of 12 randomized trials (513 participants) found NMN raised blood NAD, but most glucose and lipid outcomes did not differ from control; all 12 studies had some or high risk of bias (Zhang 2025). And “it reverses aging in mice” is just that: in elderly mice, NMN improved blood flow and endurance by increasing capillary density (Das 2018). A 2026 systematic review of 33 human and 80 rodent studies found clear target engagement in people, but functional outcomes were “heterogeneous and often null” and clinical effectiveness for anti-aging remains inconclusive (Gallagher 2026).