Safety and Metabolism-Related Outcomes of Oral Nicotinamide Mononucleotide Supplementation in Adults: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 42514320 · doi:10.3390/nu18142251
What was done
Authors systematically searched PubMed, Embase, Scopus, Web of Science, CNKI, and Wanfang through May 2026 for parallel randomized controlled trials evaluating oral nicotinamide mononucleotide (NMN) or related preparations against control interventions in adults. Outcomes assessed via random-effects meta-analyses and GRADE certainty included adverse events, serious adverse events, study withdrawals, alanine aminotransferase (ALT), aspartate aminotransferase (AST), anthropometrics, glycemic markers, lipid profiles, and blood pressure.
What was found
Across 15 included trials (doses 250 to 2000 mg/day, durations 14 days to 24 weeks; 10 trials analyzed for safety), oral NMN did not significantly increase total adverse events, serious adverse events, adverse event-related withdrawals, system-specific adverse events, ALT, or AST. Meta-analyses found no significant effects on body weight, BMI, fasting glucose, HbA1c, lipid profiles, or systolic blood pressure. Diastolic blood pressure decreased slightly, and HOMA-IR showed a non-significant downward trend (specific numerical effect sizes and confidence intervals were not provided in the abstract).
Why it matters
This review provides aggregate randomized trial evidence that short-term oral NMN supplementation up to 2000 mg/day appears safe and well-tolerated, while tempering claims regarding broad, immediate metabolic improvements in general adult populations.
Limits
The abstract does not provide exact effect sizes, confidence intervals, or total participant sample sizes. Intervention durations were relatively short (maximum 24 weeks), precluding conclusions about long-term safety or chronic metabolic benefits.
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