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Quick answers
- What is NMN? Nicotinamide mononucleotide, a compound the body converts into NAD+, a coenzyme cells need to produce energy.
- Does it raise NAD+? Yes. This is the most consistent finding in human trials, at 250–900 mg a day.
- Other benefits? Small, short trials report mixed results for walking speed, aerobic capacity, sleep and insulin sensitivity. Two 2024 reviews of the trials found no significant effect on blood sugar, cholesterol or overall physical performance.
- Does NMN increase testosterone? We found no human trial that measured it. Treat testosterone claims as unproven.
- Dosage in trials: 250 mg to 1,250 mg a day, for up to 12 weeks.
- Is it legal in the US? Yes, again. The FDA said in 2022 that NMN was excluded from supplements, then reversed that position in 2025.
What NMN and NAD+ are
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell. It is involved in energy metabolism and DNA repair, and it is needed by enzymes such as sirtuins and PARPs. NMN is one step away from NAD+ in the body’s “salvage” pathway. NR (nicotinamide riboside) is one step further back, and nicotinamide and niacin are older forms of vitamin B3 that also feed the pathway (Yoshino, Baur & Imai 2018, Cell Metab).
In animal studies, NAD+ levels fall with age. Raising them with NMN has been reported to improve energy metabolism, insulin sensitivity and physical activity in aging mice (Mills 2016, Cell Metab). NMN supplements are based on the idea that supplying the precursor can offset some of that decline in people. That idea is plausible, but it is still being tested.
NMN supplement benefits: what human trials show
Here are the main randomized, placebo-controlled trials, with the dose and length of each:
| Trial | Who | Dose & length | Main findings |
|---|---|---|---|
| Yoshino 2021, Science | 25 postmenopausal women with prediabetes and overweight | 250 mg/day, 10 weeks | Muscle insulin sensitivity and insulin signaling increased compared with placebo |
| Igarashi 2022, npj Aging | 42 healthy men aged 65+ | 250 mg/day, 6–12 weeks | Blood NAD+ rose. Gait speed and grip results were only “nominally” significant. No change in body composition |
| Liao 2021, JISSN | 48 amateur runners (40 men) | 300, 600 or 1,200 mg/day, 6 weeks, with training | Measures of aerobic capacity improved more at 600 and 1,200 mg. VO2max did not change |
| Yi 2023, GeroScience | 80 healthy middle-aged adults | 300, 600 or 900 mg/day, 60 days | Blood NAD+ rose, most at 600–900 mg. Six-minute walk distance improved. No change in HOMA-IR (insulin resistance) |
| Katayoshi 2023, Sci Rep | 36 healthy middle-aged adults | 250 mg/day, 12 weeks | NAD+ metabolites rose. Arterial stiffness “tended” to fall but did not differ significantly from placebo |
| Kim 2022, Nutrients | 108 older adults | 250 mg/day, 12 weeks, morning vs afternoon | Afternoon dosing was linked to better chair-stand performance and less drowsiness |
| Morifuji 2024, GeroScience | 60 older adults | 250 mg/day, 12 weeks | No effect on the primary stepping test. Faster 4-m walk time and better sleep-quality scores |
What the pooled evidence says. A 2024 meta-analysis of eight RCTs with 342 mostly healthy adults found that 250–2,000 mg/day had no significant effect on fasting glucose, insulin, HbA1c, HOMA-IR or blood lipids. A 2024 systematic review of ten RCTs found that changes in physical performance were not significant. It also found no serious adverse effects.
How to read this. NMN reliably raises NAD+ in blood. Whether that leads to health benefits you would notice has not been established. The trials are small and short (12 weeks at most), some were funded by NMN makers, and results differ from one measure to the next.
Benefits claimed vs what the evidence supports
| Claim you will see | What the research supports |
|---|---|
| Raises NAD+ | Supported in several human RCTs. This is the best-grounded claim. |
| Reverses aging or extends lifespan | Not shown in people. Lifespan data come from animals. |
| More energy, less fatigue | Mixed. One trial reported less drowsiness with afternoon doses. |
| Better blood sugar | One trial in women with prediabetes was positive. The 2024 meta-analysis found no overall effect. |
| Better exercise capacity or walking speed | Small positive signals in some trials. A 2024 review found no significant pooled effect. |
| Better sleep | One trial reported better sleep-quality scores in older adults. |
| Heart, brain or DNA repair benefits | Mostly animal or mechanism data. |
| Higher testosterone or libido | No human trial found. |
NMN benefits for men: does NMN increase testosterone?
Several of the trials above included men. Igarashi 2022 studied only men aged 65 and over, and Liao 2021 was mostly male runners. The measured outcomes were NAD+, muscle function and aerobic capacity. None of the human NMN trials we found measured testosterone. A PubMed search on 27 Sept 2026 returned animal studies of NMN and testicular or ovarian tissue, but no human testosterone data.
That means:
- Any product promising “higher testosterone” or “male vitality” from NMN is making a claim that human research has not tested.
- If you have symptoms of low testosterone, such as low libido, fatigue or loss of muscle, the reliable first step is a blood test through your doctor. Our testosterone booster guide explains what supplements can and cannot do.
- Erection problems can be an early sign of heart or blood-vessel disease. See a doctor rather than relying on a supplement.
What NMN may offer men, based on current evidence: higher NAD+ levels and possibly small gains in walking speed or aerobic measures, mainly in older men or men who are also training.
NMN dosage: what the trials used
| Daily dose | Where it was tested |
|---|---|
| 250 mg | Most 12-week trials (Yoshino, Igarashi, Katayoshi, Kim, Morifuji) |
| 300–900 mg | Yi 2023 dose comparison. NAD+ rose most at 600–900 mg |
| 1,200 mg | Liao 2021 runners, for 6 weeks |
| 1,250 mg | Fukamizu 2022 safety study, 4 weeks, with no safety problems found |
Best NMN supplement “1000mg”? Some products sell 1,000 mg servings. Doses around that level have only been studied for 4–6 weeks. There is no evidence that 1,000 mg works better than 250–600 mg for any health outcome, and it costs more.
Best way to take NMN
- Time of day: one trial found afternoon dosing produced the largest effects on drowsiness and leg strength (Kim 2022). This is a single finding.
- With or without food: trials don’t settle this. Follow the label.
- Consistency: the benefits reported so far appeared after weeks of daily use, not after single doses.
- Sublingual vs swallowed: a 2026 crossover study in 14 men found that sublingual NMN raised some breakdown products faster. Blood NMN and NAD+ levels were no different from swallowed NMN (Wakabayashi 2026).
Is NMN safe? Side effects and who should avoid it
In the trials above, NMN at up to 1,250 mg/day for up to 12 weeks was well tolerated. No serious adverse events were attributed to it (Fukamizu 2022; Yi 2023; Wen 2024). Long-term safety beyond about three months has not been studied.
Talk to a doctor before taking NMN if you:
- take prescription medication, particularly for diabetes (NMN has been studied for effects on insulin sensitivity)
- have cancer or a history of cancer. NAD+ is involved in cell growth, and this has not been studied in people with cancer.
- have kidney or liver disease or any ongoing health condition
- are pregnant or breastfeeding (not studied)
- are under 18
Stop taking it and seek advice if you notice side effects. Dietary supplements are not approved by the FDA for safety or effectiveness before they are sold.
Is NMN legal? The FDA status of NMN
NMN’s US status has changed twice:
- November 2022: the FDA told NMN ingredient suppliers that NMN was excluded from the definition of a dietary supplement. Its reasoning was that NMN had been authorized for investigation as a new drug before it was marketed as a supplement (NutraIngredients).
- 2023–2024: the Natural Products Association (NPA) and the Alliance for Natural Health USA filed a citizen petition in March 2023. The NPA sued the FDA in August 2024 (NutraIngredients).
- Late September 2025: in its response to the petitions, the FDA changed its interpretation. It concluded that NMN had been marketed as a supplement in the US before it was authorized for investigation as a drug, and that it is lawful in dietary supplements (NutraIngredients; NPA).
- December 2025: the FDA sent letters to the two ingredient suppliers confirming NMN is “no longer excluded” from the supplement definition (NutraIngredients).
What this does and doesn’t mean. NMN can legally be sold as a supplement in the US again. The FDA’s decision was about legal status. It was not a statement that NMN is safe or effective.
How to choose the best NMN supplement
Here is what to check on any NMN product. For a detailed look at one brand against these checks, see our Genuine Purity NMN review.
1. Stated dose, no proprietary blend
The label should state the NMN amount per capsule. 250 mg per serving matches the most-studied dose. Be cautious with “NAD+ complexes” that hide the NMN amount inside a blend.
2. Purity and a batch-specific COA
Look for a Certificate of Analysis from a named lab. It should cover identity (beta-NMN), purity percentage, heavy metals and microbes, and its lot number should match your bottle. Given the recent regulatory disruption and the number of new brands, this check matters more for NMN than for most supplements.
3. Form: powder, capsule, liposomal or sublingual
- Capsules or powder: these are what nearly all the human trials used.
- Liposomal: NMN wrapped in phospholipids, which sellers say protects it during digestion. We found no human study comparing liposomal and standard NMN. Absorption claims such as “up to 95%” come from sellers.
- Sublingual: faster changes in some breakdown products, but no difference in blood NAD+ in the one head-to-head study (Wakabayashi 2026).
4. NMN vs NR
NR (nicotinamide riboside) also raises NAD+. At 1,000 mg/day it was well tolerated and raised NAD+ in middle-aged and older adults (Martens 2018). No large trial has compared NMN with NR directly, so neither has been shown to be better.
5. “Liposomal NAD+” and NMN + resveratrol products
Some products sell NAD+ itself, often in liposomal form. There is much less human research on oral NAD+ than on NMN or NR. Many “best NMN resveratrol supplement” products combine the two because of animal research on sirtuins. We did not find a human trial of the combination, so judge each ingredient on its own evidence.
6. Reddit and reviews
Forum threads (“NMN supplement reddit”) often discuss brands, COAs and price per gram. These are useful for spotting counterfeits and testing complaints. They are not evidence that a product works.
Food with NMN: natural sources
NMN is found in small amounts in everyday foods. Mouse researchers measured it in several foods (Mills 2016, Table 1):
| Food | NMN (mg per 100 g) |
|---|---|
| Edamame | 0.47–1.88 |
| Broccoli | 0.25–1.12 |
| Avocado | 0.36–1.60 |
| Mushroom | 0–1.01 |
| Cabbage | 0–0.90 |
| Cucumber (peel / seed) | 0.65 / 0.56 |
| Tomato | 0.26–0.30 |
| Shrimp | 0.22 |
| Beef (raw) | 0.06–0.42 |
Even the richest food provides about 2 mg per 100 g, so you would need around 13 kg of edamame to match a 250 mg capsule. Food can’t realistically supply trial doses. Your body also makes NAD+ from other B3 sources, such as niacin in meat, fish and whole grains, and from tryptophan.
The NMN product we reviewed: GenuinePurity Liposomal NMN
GenuinePurity Liposomal NMN is made by Leading Edge Health Inc. Here is what its official page stated when we checked on 27 Sept 2026:
- Dose: 250 mg NMN per capsule, with a sunflower phospholipid (liposomal) layer, and “one capsule daily, preferably with meals”
- Testing: the seller says it publishes batch Certificates of Analysis and describes U.S. manufacture under cGMP
- Price: $69 per bottle listed, or a $19 first-bottle trial that converts to a $49-every-30-days subscription until you cancel. Read the subscription terms before ordering.
- Guarantee: “97 day guarantee”
Its 250 mg dose matches the most-studied amount in the trials above. Its liposomal absorption claim has not been independently tested, and no study has tested this finished product. Our Genuine Purity NMN review covers the COA portal, pricing and what we could not verify.
Check GenuinePurity Liposomal NMN on the official site
NMN FAQ
What are the benefits of NMN?
NMN reliably raises blood NAD+ levels. Small trials report mixed effects on walking speed, aerobic capacity, sleep quality and insulin sensitivity, but 2024 reviews found no significant pooled effect on blood sugar, lipids or physical performance. Anti-aging benefits in people are not established.
What are NMN benefits for men?
Trials in older men and mostly male runners found higher NAD+ and some small improvements in gait speed or aerobic measures. No study has shown effects on testosterone, libido or erections.
Does NMN increase testosterone?
We found no human trial that measured testosterone after NMN supplementation, so there is no evidence that it does. Get a blood test through your doctor if you suspect low testosterone.
How much NMN should I take?
Human trials used 250 mg to 1,250 mg a day, most often 250 mg for up to 12 weeks. NAD+ rose most at 600–900 mg in one dose comparison. Follow your product label and check with a doctor if you take medication.
What is the best way to take NMN?
Take it daily and consistently. One trial found afternoon doses had the largest effect on drowsiness and leg strength. Trials don’t settle whether to take it with food, so follow the label.
What is the best NMN supplement?
Look for a clearly stated dose (around 250 mg per serving), beta-NMN, a batch-specific COA from a named lab, and a seller with clear refund terms. No brand has been shown to be better in a head-to-head trial.
What foods contain NMN?
Edamame, broccoli, avocado, cabbage, cucumber, tomato, mushrooms, shrimp and beef contain small amounts, up to about 2 mg per 100 g. That is far below supplement doses.
Is NMN legal in the US?
Yes. The FDA said in 2022 that NMN was excluded from dietary supplements, then reversed that position in late 2025 and confirmed it is lawful in supplements. That decision concerns legal status, not safety or effectiveness.
Sources and editorial status
- Human trials: Yoshino 2021, Igarashi 2022, Liao 2021, Yi 2023, Katayoshi 2023, Kim 2022, Morifuji 2024, Fukamizu 2022, Wakabayashi 2026, Martens 2018 (NR)
- Reviews: Chen 2024 meta-analysis, Wen 2024 systematic review, Yoshino 2018
- Food content: Mills 2016
- Regulatory: NutraIngredients, Sept 2025, NutraIngredients, Dec 2025, Natural Products Association
- Related: Genuine Purity NMN review, DIM supplementation benefits, GenF20 Plus review
Reviewed by the Mens Fitness editorial team. Sources checked 27 September 2026.