NMN, short for nicotinamide mononucleotide, is a molecule naturally found in our bodies and some foods. But what's making headlines is its potential as an anti-aging supplement. NMN is a precursor to NAD+, a coenzyme crucial for energy production, cellular repair, and gene expression. NAD+ levels decline with age, and some scientists believe increasing NAD+ levels could slow aging and combat age-related diseases.