NAD+

NAD+ (Nicotinamide Adenine Dinucleotide) is a fundamental pyridine nucleotide coenzyme present in every living cell. Essential electron carrier in mitochondrial respiration (ATP production), substrate for sirtuins (longevity proteins), PARPs (DNA repair), and CD38 (immune signaling). NAD+ levels decline ~40-50% between age 20 and 50. Injectable form bypasses oral precursor pathways for direct delivery. Research compound for cellular energy optimization.