Evidence Level
NMN research has advanced from preclinical studies to human trials, producing promising yet mixed results. Yi et al. (2022) demonstrated that oral NMN is bioavailable and elevates NAD+ levels in humans, while Yoshino et al. (2021) found improved insulin sensitivity in postmenopausal women following NMN supplementation. Liao et al. (2022) reported enhanced aerobic capacity in recreational runners after NMN administration.
A systematic review by Gallagher and Emmanuel (2026) of 33 human and 80 rodent studies indicated that NAD+ supplementation improves metabolic and mitochondrial function in rodents but has inconsistent effects on human healthspan outcomes. Wang et al. (2025) meta-analyzed nine randomized controlled trials involving 412 participants, concluding that NMN supplementation significantly improves muscle mass, reduces ALT levels, and lowers insulin resistance in middle-aged and elderly adults.
However, Zhang et al. (2025) systematically reviewed 12 randomized controlled trials (n=513) and found that while oral NMN elevates blood NAD+ levels, it does not significantly improve fasting glucose, triglycerides, total cholesterol, LDL-C, or HDL-C in adults. Prokopidis et al. (2025) meta-analyzed 12 studies involving 345 older adults and found no significant effects of NMN or NR on skeletal muscle mass or function in individuals over 60 years old.
Despite these findings, the NMN vs NR debate persists, with both compounds raising NAD+ levels but NMN potentially having a slight edge due to its closer enzymatic proximity. Larger, longer-duration human trials are needed to confirm longevity-specific outcomes.