Jarrow Formulas® Nicotinamide Mononucleotide (NMN) is an efficient precursor to the essential vitamin B3 metabolite, NAD+. NAD+ is essential to cellular energy production and mitochondrial function.* Levels of NAD+ decline with aging and high caloric intake, which can compromise mitochondrial function.* NAD+ is a required cofactor for sirtuins (SIRT), enzymes that promote healthy aging by regulating gene expression, DNA repair, mitochondrial biogenesis and energy metabolism.