NAD

NAD (nicotinamide adenine dinucleotide) is produced naturally by the body, but levels decline with age. While you cannot effectively take direct NAD+ supplements because the large molecules are poorly absorbed, you can take supplements—specifically NMN (nicotinamide mononucleotide) or NR (nicotinamide riboside)—that act as precursors, which the body uses to create its own NAD+.  NAD+, helps with serotonin and weight loss.