Biochemistry
Nicotinamide Adenine Dinucleotide (NAD+)
Definition
Nicotinamide Adenine Dinucleotide (NAD+) is an essential coenzyme present in all living cells that serves as a critical electron carrier in mitochondrial oxidative phosphorylation and a substrate for enzymes including sirtuins, PARPs, and CD38. NAD+ levels decline with age, contributing to mitochondrial dysfunction, impaired DNA repair, and metabolic dysregulation. Strategies to boost NAD+ levels, including supplementation with precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), as well as peptide-based interventions, are active areas of longevity research.