Safety and Metabolism-Related Outcomes of Oral Nicotinamide Mononucleotide Supplementation in Adults: A Systematic Review and Meta-Analysis

Yang W, Huang J, Tang Z, Chen C, Sun Y · Nutrients

The best current safety synthesis: NMN did not increase overall adverse events, serious adverse events, withdrawals, system-specific events, ALT or AST. No effect on body weight, BMI, fasting glucose, HbA1c, lipids or systolic pressure; diastolic pressure fell slightly and HOMA-IR trended down without reaching significance.

Population

Adults across 15 randomised trials (10 contributing safety data), NMN 250-2,000 mg/day for 14 days to 24 weeks

Intervention

Oral NMN or NMN-containing preparations

Comparator

Placebo, blank control or matched background intervention

Limitations

Maximum trial duration 24 weeks — this establishes short-term tolerability, not long-term safety. GRADE certainty was limited by the size and quality of the underlying trials.