“NMN reverses aging”

## Animal Evidence (Compelling) David Sinclair's lab and others have shown that NMN/NR supplementation reverses some age-related physiological declines in mice: muscle function, energy metabolism, insulin sensitivity, and even lifespan extension by ~5–10% in some studies. These findings are mechanistically plausible via NAD+ restoration and SIRT1/SIRT3 activation. ## Human Evidence (Very Limited) A 2021 clinical trial (Yoshino et al., *Science*, 2021) showed 250mg/day NMN for 10 weeks improved skeletal muscle insulin sensitivity in postmenopausal women with prediabetes — a meaningful but specific and modest finding. A 2022 trial (Yi et al.) showed NMN raised blood NAD+ levels dose-dependently but did not measure clinical outcomes. No trial has demonstrated reversal of biological aging measures, meaningful lifespan data, or clinically significant outcomes in healthy humans. ## Safety Short-term safety appears acceptable at standard doses (250–1,000 mg/day). Long-term safety is unknown. NAD+ is a substrate for cancer cell metabolism — theoretical concern about promoting cancer growth in people with subclinical malignancy remains unresolved.