○ Evidence tier 4 — Human RCT — biomarker endpoint

Record verify: primary source pending

DesignSystematic review and meta-analysis of randomized controlled trials
DOI10.1007/s11892-024-01557-z
Citation statusdoi verified via Crossref 2026-07-12 (Curr Diab Rep 2025;25, 'Effects of Nicotinamide Mononucleotide on Glucose and Lipid Metabolism in Adults: A Systematic Review and Meta-analysis of Randomised Controlled Trials'). A second concordant meta-analysis (Crit Rev Food Sci Nutr 2025;65:4382-4400, doi 10.1080/10408398.2024.2387324) reaches a similar null conclusion. PMID: needs_primary_fulltext.

Five-qualifier claim

Species / populationAdults pooled across randomized controlled trials of NMN (systematic review and meta-analysis).
Exposure, route, scheduleOral NMN across included RCTs (varied doses/durations).
Comparator / durationPlacebo-controlled RCTs pooled; meta-analytic synthesis.
Endpoint / numeric resultNo statistically significant effect of NMN on glucose or lipid metabolism across the pooled RCTs.
What it did NOT establishA null meta-analysis for metabolic biomarkers — it does not support a metabolic, functional, or lifespan benefit of NMN.

Primary reference

https://doi.org/10.1007/s11892-024-01557-z

Exact identifier confirmed against the primary record via Crossref/ClinicalTrials.gov where stated in the citation status; anything marked needs_primary_fulltext is not yet confirmed.