Nicotinamide Mononucleotide (NMN)

Nicotinamide mononucleotide (NMN) is a precursor for NAD+ biosynthesis. In vitro and in vivo studies have demonstrated that NMN supplementation increases NAD+ 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.

NAD+ Precursors

NAD+ precursors are molecules that boost the levels of nicotinamide adenine dinucleotide (NAD+), an essential coenzyme involved in key physiological processes, including energy metabolism, DNA repair, and immune function regulation. NAD+ concentration in human skin, blood, liver, muscle, and brain are thought to decrease with age. Finding ways to increase NAD+ status could possibly influence the aging process and associated metabolic sequelae.

Role in Age-Related Disease Mitigation

Supplementation with NAD+ precursors has shown promise in mitigating age-related diseases. NMN has demonstrated therapeutic potential in age-related chronic conditions such as diabetes, cardiovascular issues, and cognitive impairment.

Human Studies

Human studies have shown NMN to improve muscle insulin sensitivity in prediabetic women, enhance aerobic capacity in runners, and reduce fatigue in older adults. Preclinical research suggests potential benefits for diabetes-related cognitive deficits, heart failure, cognition, and fertility, which require further human confirmation. NMN is also considered safe and well-tolerated in dosages of 250–1000 mg/day.

Safety and Physiological Effects

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+ biology to clarify the potential effects of NMN supplementation and to shed light on future study directions.