Nicotinamide Mononucleotide (NMN or β-NMN) is a nucleotide derived from ribose, nicotinamide, nicotinamide riboside, and niacin. It acts as a natural precursor to NAD+, which is a critical component in cellular energy production. NAD+ levels are at their highest at birth and naturally decrease with aging, dropping to less than about 50% in middle age. This reduction in NAD+ contributes to a decrease in the rate of all cellular functions, which is likely one of the primary causes of many age-related deteriorations.