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: verified against primary source
| 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 is not confirmed; see identifier status. |
Identifiers: DOI verified; PMID not reported; trial registry id not reported. Record-level verification and identifier-level status are separate: a record can be verified against its primary publication on one identifier while another is simply not confirmed. No identifier is fabricated, and none is left in a “pending” state.
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 names the source and the date. An identifier that is not confirmed is named as such in the identifier row above, never filled in from a secondary source.