Evidence matrix
These scores describe different evidence domains. A strong mechanism cannot compensate for missing human outcomes, and a useful clinical effect need not imply slower biological ageing.
What has been shown in humans?
Randomised trials demonstrate changes in NAD metabolites and occasional improvements in selected outcomes such as muscle insulin sensitivity in a specific population. Meta-analyses have not established dependable benefits for glucose, lipids, muscle mass or physical function across older adults.
What remains uncertain?
Long-term safety, clinical relevance of raising NAD, optimal population, product quality and whether benefits persist beyond short trials are unresolved.
Doses used in research
Safety and interpretation
- Short trials generally report acceptable tolerability, but this does not establish multi-year safety.
- Cancer biology and NAD metabolism are complex; mechanistic arguments alone cannot establish benefit or harm in people with active cancer.
- Product purity and regulatory status vary by country and supplier.
Primary sources and evidence reviews
Positive outcome in a specific population; it should not be generalised to universal anti-ageing benefit.
Review finding no support for preserved muscle mass or function in adults with a mean age over 60.
Short-term trial reporting increased blood NAD and acceptable tolerability up to the tested doses.
Editorial note
This dossier was last reviewed on 13 July 2026. Ratings can change when larger trials, adverse-event data or better systematic reviews appear. Corrections should alter the page rather than being buried in a social-media thread.