β-Nicotinamide adenine dinucleotide (NAD) is widely used in biochemical research as a coenzyme in redox reactions, playing a critical role in metabolic processes such as glycolysis, the citric acid cycle, and oxidative phosphorylation. It is essential for studying cellular energy production and enzyme kinetics. In biotechnology, NAD is utilized in enzymatic assays and biosensors to measure metabolic activity or detect specific biomolecules. It also finds applications in the development of therapeutic strategies targeting age-related diseases, as NAD levels decline with aging and are linked to mitochondrial dysfunction. Additionally, NAD is employed in the production of high-value chemicals through biocatalysis, where it facilitates the regeneration of cofactors in enzymatic reactions.