Nicotinamide Riboside for Aging
Nicotinamide riboside reliably and safely lifts blood NAD+, but controlled human trials and meta-analyses show no convincing benefit on the outcomes that define aging well, so it does not work as an anti-aging supplement on current evidence.
Why this grade7-layer evidence engine
This pair earns a Counter-Evidence (D) grade because the human evidence splits cleanly between a biomarker that moves and clinical endpoints that do not. Multiple RCTs and reviews confirm NR safely raises the NAD+ metabolome (a roughly 2.6-fold rise in blood NAD+ in one trial, PMID 37994989), but a 2023 systematic review found NR has no effect on outcomes like insulin sensitivity, energy expenditure, or exercise capacity (PMID 37068054), and a 2023 critical appraisal of 25 human studies found few clinically relevant effects and flagged a literature-wide tendency to exaggerate them (PMID 37478182).
The endpoints that actually matter for aging stay null. A 2025 meta-analysis concluded that NMN and NR do not preserve muscle in adults over 60, with no significant effect on skeletal muscle index (MD -0.42, p=0.14) or gait speed (PMID 40275690). An early crossover RCT raised NAD+ but found only suggestive, unconfirmed signals on blood pressure and arterial stiffness (PMID 29599478), and the only biological-age hint comes from an underpowered n=20 pilot supplied by industry, which is hypothesis-generating at best (PMID 37994989).
Regulators and clinicians reinforce this gap. The US FDA accepts nicotinamide riboside chloride as GRAS, but that is a safety and legality judgment about an ingredient, not an endorsement of any anti-aging effect. Clinical sources including NIH ODS, Cleveland Clinic, and Harvard Health take a cautious stance and stop short of recommending it for aging, which is consistent with treating a real pharmacologic NAD+ effect as no substitute for a demonstrated healthspan benefit.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.496
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 negative 主導 (2 negative > 0 positive)，下層 RCT 不能推翻
- apply_hec_override — HEC-1 高階證據 negative — 強制由 C 改為 D
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status