Study record
Chronic nicotinamide riboside elevates NAD⁺ in healthy adults (Martens et al., 2018)
Human RCT — biomarker endpoint
○ Evidence tier 4 — Human RCT — biomarker endpoint
Record verify: primary source pending
| Design | Randomized, double-blind, placebo-controlled crossover trial (biomarker) |
| N | 24 |
| DOI | 10.1038/s41467-018-03421-7 |
| Citation status | doi verified via Crossref 2026-07-12 (Nat Commun 2018;9:1286, Martens et al., 'Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults'). NOTE: NCT03821623 is a SEPARATE, later University of Colorado Boulder Phase 2 NR blood-pressure/arterial-stiffness trial — verified via ClinicalTrials.gov v2 API (randomized, triple-masked, n=118 est., RECRUITING as of 2025-02, NO published results) — do NOT conflate it with this 2018 paper. This 2018 trial's own registry id + PMID: needs_primary_fulltext. |
Five-qualifier claim
| Species / population | Healthy middle-aged and older adults (crossover RCT, ~24 completers). |
| Exposure, route, schedule | Oral NR 500 mg twice daily (1000 mg/day) for 6 weeks. |
| Comparator / duration | Placebo-controlled, double-blind, randomized crossover; 6-week periods. |
| Endpoint / numeric result | Well tolerated; roughly doubled whole-blood NAD+; a suggestive reduction in systolic blood pressure and aortic stiffness in a subgroup with elevated baseline. |
| What it did NOT establish | NAD+ is a biomarker; the BP/stiffness signal was secondary/subgroup, not a powered clinical outcome, and there is no lifespan endpoint. |
Interventions
Primary reference
https://doi.org/10.1038/s41467-018-03421-7
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.