Nicotinamide adenine dinucleotide (NAD) is a key coenzyme in cell metabolism and plays a central role as an electron carrier in enzyme-catalyzed REDOX reactions. NAD supports energy generation and cell function maintenance by accepting or transferring electrons in metabolic pathways such as glycolysis, tricarboxylic acid cycle, and electron transport chain. Its role in dehydrogenases reactions is particularly prominent, ensuring efficient operation of cell metabolism. By improving the catalytic efficiency of enzymes, NAD plays an irreplaceable role in maintaining cell health, energy metabolism and overall metabolic balance.