Nicotinamide adenine dinucleotide (NAD+) is a critical coenzyme involved in hundreds of metabolic reactions. Research into NAD+ levels and cellular function continues to accelerate.
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme present in all living cells, playing an essential role in cellular respiration, DNA repair, and gene expression regulation. NAD+ acts as an electron carrier in redox reactions, shuttling electrons from metabolic substrates to the mitochondrial electron transport chain where ATP is produced. Intracellular NAD+ levels decline with age in multiple tissues, a phenomenon that has generated considerable research interest.
NAD+ is required for the activity of key mitochondrial enzymes including Complex I of the electron transport chain. When NAD+ availability is reduced, mitochondrial efficiency declines, resulting in decreased ATP output and increased production of reactive oxygen species (ROS). Studies in aged mouse models have associated NAD+ repletion with improved mitochondrial biogenesis markers and metabolic parameters.
Beyond its role as an electron carrier, NAD+ serves as a substrate for two major enzyme classes: sirtuins (SIRT1–7) and poly(ADP-ribose) polymerases (PARPs). Sirtuins are NAD+-dependent deacylases implicated in chromatin remodeling, DNA damage response, and metabolic regulation. PARP enzymes consume NAD+ during DNA repair processes. Research suggests that competition between these pathways for NAD+ influences cellular stress responses and aging trajectories.
For in-vitro research use only. Not for human or veterinary use.