Placebo-controlled randomized double-blind parallel-group trial of the safety of overdose intake of nicotinamide mononucleotide

The safety of nicotinamide mononucleotide (NMN) manufactured by Teijin Limited was evaluated in a human overdose intake study involving placebo-controlled randomized double-blind parallel-group comparison. Thirty healthy Japanese volunteers, comprising men and women aged 20–64 years old, were divided into high-dose, low-dose, and placebo groups. NMN doses for these groups were set at 1,500, 750, and 0 mg/day, respectively, for an intake period of 4 weeks. To evaluate the safety of overdose intake of NMN, we conducted medical interviews and examined subjective symptoms, body weight, body mass index, blood pressure, pulse rate, hematological testing, biochemical testing, and urine testing at 0, 2, and 4 weeks of intake. As there were no dropouts, we analyzed the data from all 30 participants. We found no problematic findings or test result changes during any medical interviews or tests throughout the study period, confirming the safety of 1,500 mg/day NMN ingestion for 4 weeks. Blood nicotinamide adenine dinucleotide (NAD+) levels increased significantly, suggesting that orally ingested NMN was transferred throughout the body and converted to NAD+. In this study, NMN did not impact telomere length.