NMN is an inherent substance in human body, and it is also rich in some fruits and vegetables. In the human body, NMN is the most direct precursor of NAD+, and its function is manifested through NAD+, which can generate signal molecules with NAD+ consuming enzymes such as type III histone deacetylase (Sirtuins), polyadenylic acid diphosphate ribose transferase (PARP), cyclic ADP ribose synthetase, etc., and regulate numerous cell signal pathways and participate in DNA repair , Gene stability maintenance, calcium salt balance, mitochondrial homeostasis maintenance, immune response regulation, redox state regulation, etc.