Nicotinamide riboside, a vitamin B3 dietary supplement marketed for healthy aging, reliably raises a molecule cells use for energy and repair, but benefits for healthy aging remain unproven: most measured outcomes did not improve compared with placebo. Short-term safety at common doses looks reassuring, with mostly mild digestive complaints. The largest trial found modestly faster worsening in early Parkinson's disease, and questions about cancer growth and heart risk remain open. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Whole-blood NAD+ | No established target; track the rise from own baseline | Expected to change; confirms absorption |
| Homocysteine (a vascular-risk amino acid) | About 5–15 µmol/L | Safety check; a rise prompts dose reduction |
| ALT and AST (liver enzymes) | Laboratory-specific upper limit, typically about 40–55 U/L | Safety check; a rise prompts stopping |
| Home blood pressure (if on antihypertensives) | No established target for NR use; track change from own baseline | Safety check; a drop with light-headedness prompts review |
Cadence: Baseline before starting; NAD+ and homocysteine at 4–8 weeks after starting or any dose increase; then every 6–12 months at 1 g/day or more, with liver enzymes; annual checks at label doses (common practice); home blood pressure several times weekly for the first month if on antihypertensives.