Claim Check: "NAD+ Boosters Restore Youthful Energy"
A plain-language check of the claim that NAD+ boosters such as NMN and nicotinamide riboside restore youthful energy: what human trials measured, and where the evidence stops.
Content last updated . This page has not been medically reviewed.
Labels used here: promising but limited (early human data, small or short), mixed (studies disagree), insufficient evidence (too little to judge), marketing claim (a statement not tested as worded). A fuller guide is at How We Label Evidence in Longevity Research.
What the claim gets right
Reviews report that NMN and NR are tolerated in the studies done and can raise NAD+ and related molecules. [1] In a 2 x 6-week randomized crossover trial in healthy middle-aged and older adults, NR was well tolerated and stimulated NAD+ metabolism. [2] Chemistry that moves is not the same as a person feeling or functioning better, which is where the claim goes beyond the data.What human trials measured
| Study (design) | What was measured | What it reported |
|---|---|---|
| NMN, 10 weeks, randomized placebo-controlled, postmenopausal women with prediabetes who were overweight or obese | Muscle insulin sensitivity | Insulin-stimulated glucose disposal rose with NMN and not with placebo. [3] |
| NR, 21 days, 12 older men, crossover (study amount 1 g a day) | Muscle NAD+ chemistry and mitochondrial function | Muscle NAD+ metabolites rose, without altering mitochondrial bioenergetics. [4] |
| NR, 12 weeks, 40 middle-aged obese insulin-resistant men | Muscle mitochondria | Steady-state muscle NAD+ levels and mitochondrial respiration were unchanged. [5] |
| NMN, 12 weeks, 108 older Japanese adults (study amount 250 mg a day) | Sleep, fatigue, grip, sit-to-stand, walking | Sit-to-stand improved in every group, placebo included; the afternoon NMN group had the largest effect. [6] |
Two NR trials in different groups of men disagree on whether muscle NAD+ rises, and neither found a change in how muscle mitochondria worked. The insulin finding is a metabolic result in people with prediabetes, not a measure of energy. The NMN trial's own placebo groups improved on the chair-stand test, which is why placebo-controlled comparisons matter.
Fatigue and energy specifically
A 2026 network meta-analysis pooled 27 studies (n = 1,599; 25 randomized trials and 2 quasi-experimental tests) of NAD+ precursors. It reported that no precursor significantly improved perceived fatigue or sleep quality. NMN showed some benefit in endurance, and strength was unchanged. [7] That analysis mixed several compounds, populations and doses, so it is a signal to test further, not a verdict. A systematic review of oral NMN also found no clear broad metabolic benefit across body weight, glucose or lipids in short trials (14 days to 24 weeks), and no increase in adverse events. [8]Where the evidence stops
- Duration and size: trials were short and mostly small; reviewers say small samples limit interpretation and that the evidence raising NAD+ improves physiological function is unclear. [1]
- Outcome type: raising NAD+ is a biomarker change, not a health outcome.
- Conflicts of interest: authors of the muscle insulin trial disclosed patent-licensing connections to NMN, [3] and an NR muscle study disclosed links to a company that licenses NR. [4] Disclosure does not make findings wrong; it is context.
- "Youthful": Proper evidence not found for a trial showing older adults reaching younger levels of energy. We checked the human trials above and the two reviews.
How to read a similar claim
Ask what was measured (blood level, test score, or how people feel), for how long, against what comparator, and who paid. For the biology see NAD+ Biology and Its Decline With Age, for each compound NMN: Human Trial Evidence and Regulatory Status, and for the wider goal-based view NAD, NMN and Longevity Claims. If you take medicines or have a health condition, talk with a clinician before adding a supplement; see medication interactions.Frequently asked questions
Do NAD+ boosters give you more energy?
In the trials we read, they raised NAD+ markers in some studies, but a 2026 meta-analysis found no precursor significantly improved perceived fatigue. [7] Energy as people feel it was not the main measure in most trials.
Does raising NAD+ reverse aging?
Reviewers say it is unclear that raising NAD+ improves physiological function in people. [1] Animal and cell results do not show the same in humans.
Are NMN and NR safe?
Short trials (14 days to 24 weeks) of NMN found no clear increase in adverse events. [8] Long-term safety was not established in those trials.
Is a placebo effect a problem in these trials?
It can be: in the 12-week NMN trial, sit-to-stand times improved in all groups, including placebo. [6]
References
- Dietary supplementation with NAD+-boosting compounds in humans: current knowledge and future directions. J Gerontol A 2023. PubMed 37068054. Read 2026-10-22 (abstract via Europe PMC).
- Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun 2018. PubMed 29599478. Read 2026-10-22.
- Yoshino M et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science 2021. PubMed 33888596. Read 2026-10-22.
- Elhassan YS et al. Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signatures. Cell Rep 2019. PubMed 31412242. Read 2026-10-22.
- Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men. J Physiol 2020. PubMed 31710095. Read 2026-10-22 (abstract via Europe PMC).
- Kim M et al. Effect of 12-week intake of nicotinamide mononucleotide on sleep quality, fatigue, and physical performance in older Japanese adults. Nutrients 2022. PubMed 35215405. Read 2026-10-22.
- Domain-specific effects of NAD+ precursors on fatigue and functional performance: a systematic review and network meta-analysis. Front Nutr 2026. PubMed 42774067. Read 2026-10-22 (abstract via Europe PMC).
- Safety and metabolism-related outcomes of oral nicotinamide mononucleotide supplementation in adults: a systematic review and meta-analysis. Nutrients 2026. PubMed 42514320. Read 2026-10-22 (abstract via Europe PMC).