NAD⁺ & NICOTINAMIDE BIOLOGY

The Master Molecule of Energy and Longevity — and It Is Running Out.

Nicotinamide Adenine Dinucleotide (NAD⁺) is the central coenzyme of cellular energy metabolism — essential for the electron transport chain, mitochondrial oxidative phosphorylation, and the conversion of food into ATP. It is also the substrate for sirtuins (the longevity enzymes), PARP enzymes (DNA repair), and CD38 (immune regulation). NAD⁺ levels decline by approximately 50% between the ages of 40 and 60 — a decline that correlates directly with the loss of mitochondrial function, DNA repair capacity, and cellular resilience that defines biological ageing. Supplementation with NAD⁺ precursors — niacin (vitamin B3), nicotinamide riboside (NR), and nicotinamide mononucleotide (NMN) — raises tissue NAD⁺ levels with demonstrated effects on energy, cognition, and metabolic health. The NR vs NMN vs niacin debate, the role of tryptophan as a precursor, and the impact of chronic inflammation on NAD⁺ consumption via PARP activation are central controversies in this rapidly advancing field.