NMN

Nicotinamide mononucleotide (NMN) is a precursor for NAD+ biosynthesis. ^[1] NMN is one of two key NAD+ intermediates, alongside nicotinamide riboside (NR), that have been extensively studied for their therapeutic potential. ^[2]

Because NAD+ levels in the body deplete with aging, NMN, as a precursor of NAD+, can slow down this process by elevating NAD+ levels in the body. ^[3] 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. ^[1] The molecular targets and networks of NMN have been analyzed in core aging mechanisms such as DNA damage repair, mitochondrial function regulation, inflammatory response balance, gut microbiota remodeling, and autophagy pathway activation. ^[4]

Most studies evaluating the effects of NMN have been conducted in cell or animal models, so a concern remains regarding the safety and physiological effects of NMN supplementation in the human population. ^[1] A number of in vivo studies have indicated affirmative therapeutic results for various age-induced complications with NMN supplementation, while human clinical trials remain limited and ongoing. ^[3] For the established NAD+ precursors nicotinamide riboside and nicotinamide mononucleotide, further large-scale studies are needed to determine optimal dose, administration routes and frequency, as well as long-term safety and interindividual variability in response. ^[5] Critical issues such as long-term safety and efficacy of NMN still require in-depth research. ^[4]

The promotion of NMN as an antiaging health supplement has gained popularity, and proper clinical investigations are urgently needed to find out the effectiveness and safety of NMN supplementation. ^{[1] [3]} NAD+ precursors including NMN are among eight promising drugs and natural compounds being tested in the clinic as candidate anti-aging medicines. ^[6]