Longevity & Aging · Supplements
Do NAD+ booster supplements improve fitness?
The claim, precisely: NAD+ precursors (NMN, NR) improves physical capacity
Contested Longevity & Aging 💰 Industry COI noted🔬 Includes disconfirming
RefutedContestedStrong support
consensus score 0.06
Unclear — evidence is mixed to negative; better studies find no real strength or endurance benefit.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
1 support 0 contradict 9 tested null 6 mixed · 16 sources, 1 independent group
What the evidence shows
Whether NMN/NR improve endurance/strength/clinical metabolic outcomes - the honest nulls live here. Two meta-analyses find no significant functional benefit despite NAD elevation; positive signals are low-quality, industry-linked, or rest on secondary endpoints.
The evidence (16)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Shoji 2025 · Aging Cell | RCT | mixed | moderate | Werner-syndrome crossover: NR improved some progeroid/metabolic markers but evidence for physical-capacity gain limited and disease-specific |
| Prokopidis 2025 · J Cachexia Sarcopenia Muscle | meta-analysis | tested-null | moderate | [FT-verified] FT: no sig effect SMI/grip/gait (CIs cross 0) |
| NIH 2020 ClinicalTrials.gov | RCT | tested-null | low | Sole completed registered NMN organ-system trial; sparse registry base consistent with weak physical-capacity evidence |
| Yoshino 2021 · Science | RCT | mixed | moderate | Imai-lab NMN RCT: improved muscle insulin sensitivity in prediabetic women but no change in body weight, lipids or other endpoints |
| Igarashi 2022 · NPJ Aging | RCT | mixed | moderate | NMN 250mg up to 12wk raised NAD+ in older men; only nominal gait-speed/left-grip gains, no body-composition change - weak, secondary-endpoint signal |
| Ahmadi 2023 · JCI Insight | RCT | tested-null | moderate | Crossover in CKD: NR (and CoQ10) did not improve VO2peak or work efficiency vs placebo; NR lowered submaximal VO2 - null for aerobic capacity |
| Dollerup 2020 · J Physiol | RCT | tested-null | moderate | NR did not improve muscle mitochondrial respiration, content or morphology in obese insulin-resistant men |
| Orr 2024 · GeroScience | RCT | tested-null | moderate | NR 1g/d in MCI raised NAD+ but did not improve cognition; walking speed improved only in placebo (practice effect) - null for function |
| Liao 2021 · J Int Soc Sports Nutr | RCT | mixed | low | [FT-verified] FT n=12/arm single team no COI decl; improved submax thresholds NOT VO2max/peak; weaker than supports |
| Christen 2026 · Nat Metab | RCT | mixed | moderate | Head-to-head RCT of three NAD+ precursors: differential NAD+ raising but clinical/functional translation modest - precursor pharmacodynamics outpace outcomes |
| McDermott 2024 · Nat Commun | RCT | supports | moderate | NICE RCT n=90 PAD: 6mo NR improved 6-min walk vs placebo (+17.6m; +31m in >=75% adherent); resveratrol added no benefit - positive physical-capacity signal ⚠️ correction-on-file (Crossref) - kept, corrigendum not retraction |
| Zhang 2025 · Crit Rev Food Sci Nutr | meta-analysis | tested-null | moderate | [FT-verified] 12 studies/513 raises NAD but clinical outcomes NS; authors call benefit exaggerated |
| Morifuji 2024 · GeroScience | RCT | mixed | moderate | NMN 250mg/12wk: primary stepping-test endpoint NULL; only secondary 4m-walk and sleep improved |
| Berven 2023 · Nat Commun | RCT | tested-null | moderate | NR-SAFE: high-dose NR safe in PD, raised NAD+; UPDRS change confounded by levodopa timing - no robust functional/capacity benefit |
| Norheim 2024 · Nat Aging | RCT | tested-null | moderate | NR vs placebo in COPD: no improvement in airway inflammation; functional/capacity endpoints not benefited |
| Lin 2025 · GeroScience | RCT | tested-null | moderate | Pilot RCT: NR+exercise NOT superior to placebo+exercise for systolic BP/PWV in older hypertensives; exercise-capacity benefit not demonstrated |
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.