The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update

The importance of nicotinamide adenine dinucleotide (NAD thorn ) in human physiology is well recognized. As the NAD thorn concentration in human skin, blood, liver, muscle, and brain are thought to decrease with age, finding ways to increase NAD thorn status could possibly influence the aging process and associated metabolic sequelae. Nicotinamide mononucleotide (NMN) is a precursor for NAD thorn biosynthesis, and in vitro/in vivo studies have demonstrated that NMN supplementation increases NAD thorn concentration and could mitigate aging-related disorders such as oxidative stress, DNA damage, neurodegeneration, and inflammatory responses. The promotion of NMN as an antiaging health supplement has gained popularity due to such findings; however, since most studies evaluating the effects of NMN have been conducted in cell or animal models, a concern remains regarding the safety and physiological effects of NMN supplementation in the human population. Nonetheless, a dozen human clinical trials with NMN supplementation are currently underway. This review summarizes the current progress of these trials and NMN/NAD thorn biology to clarify the potential effects of NMN supplementation and to shed light on future study directions.