NAD+ Supplements: Do They Work?
NAD+ pills raise NAD+ in the blood. Whether that makes you healthier is a smaller, messier set of trials. Here is what those trials measured, and how to shop.
Quick Summary
Buy for the blood-level effect only if you accept that health results are early. Check that the bottle actually contains the ingredient.
What NAD+ is, and why people take a pill
NAD+ helps cells turn food into energy. It is also used by enzymes involved in DNA repair. Levels in some tissues fall with age. Most of that age pattern comes from animal studies, including mice. The supplement idea is simple: take a precursor, and NAD+ in the blood goes back up.
The first part is now well supported in people. Blood NAD+ goes up. The second part, that higher NAD+ makes you healthier or slows aging, has not been shown in human trials. Mouse lifespan studies are not people, so they are not used as a buying reason here.
These trials tested oral capsules or similar pills. They do not tell you what an IV NAD+ drip does.
NAD+ benefits: what the human trials found
| Feature | Who and how long | Dose | What changed | Limits |
|---|---|---|---|---|
| Martens 2018, Nature Communications | 24 healthy adults, ages 55–79. Two 6-week periods, each person took both NR and placebo. | NR 500 mg twice a day | NAD+ in blood cells up about 60%. Blood pressure did not fall significantly in the whole group. In an exploratory look at 13 people with higher blood pressure, systolic pressure was about 10 mmHg lower. | Small. The blood-pressure look was exploratory. NR supplied by ChromaDex. |
| Dollerup 2018, American Journal of Clinical Nutrition | 40 men with obesity, ages 40–70, for 12 weeks. | NR 1,000 mg twice a day | No improvement in insulin sensitivity, body composition, or energy expenditure. No safety signal that stood out. | Men only. One population. |
| Remie 2020, American Journal of Clinical Nutrition | 13 adults with overweight or obesity, 6-week crossover. | NR 1,000 mg a day | No change in insulin sensitivity. A small change in fat-free mass. | Very small. ChromaDex support was disclosed. |
| Yoshino 2021, Science | 25 postmenopausal women with prediabetes and overweight, 10 weeks. 13 took NMN and 12 took placebo. | NMN 250 mg a day | Muscle insulin sensitivity up 25% (plus or minus 7%). No change in blood glucose, blood pressure, lipids, liver fat, or body composition. No adverse events reported. | Very small. A published comment noted the groups started with different liver fat (6.3% vs 14.8%). |
| Yi 2023, GeroScience | 80 healthy adults, ages 40–65, for 60 days, at two sites in India. | NMN 300, 600, or 900 mg a day versus placebo | Blood NAD+ rose. Six-minute walk distance improved versus placebo. HOMA-IR, an insulin-resistance score, did not change. No safety issues reported. | Short. The walk test was not the main reason the trial was built. |
| Conze 2019, Scientific Reports | 140 healthy adults with overweight, 8 weeks. | NR 100, 300, or 1,000 mg a day versus placebo (Niagen, a ChromaDex product) | Whole-blood NAD+ up 22%, 51%, and 142%. Side effects no different from placebo. No flushing. | This was a safety and dose study, not a test of feeling healthier. |
Every trial agrees that NAD+ in the blood rises. Better blood sugar, the outcome many people hope for, mostly did not move in the larger NR trials. The positive NMN results are small and short and need repeating. None of these trials measured lifespan or long-term disease risk.
NMN vs NR, and vs NAD+ on the label
| Feature | NMN | NR | NAD+ written on the label |
|---|---|---|---|
| What it is | Nicotinamide mononucleotide, one step from NAD+ | Nicotinamide riboside, two steps from NAD+ | The coenzyme itself |
| Raises NAD+ in people? | Yes, in Yoshino 2021 and Yi 2023 | Yes, in Martens 2018 and Conze 2019 | Comparable oral trials were not in this set |
| Health outcomes | Small positive results in two short trials | Mostly no change in insulin sensitivity or body composition | Not established from these trials |
| US status | FDA's Sept 29, 2025 letter says NMN is not excluded from the dietary-supplement definition because it was marketed as a supplement before it was authorized for drug investigation. New-dietary-ingredient rules still apply. | Sold as a supplement | Sold as a supplement |
The FDA letter is Donald Prater's response to a citizen petition, docket FDA-2023-P-0872. If you are choosing between NMN and NR, these trials do not pick a winner. Whether the bottle matches its label matters more.
NAD side effects
In the trials above, side effects were mild and no more common than with placebo. Conze 2019 found no difference from placebo at up to 1,000 mg of NR a day for 8 weeks, and no flushing. Yoshino 2021 reported no adverse events at 250 mg of NMN for 10 weeks. Yi 2023 reported no safety issues at up to 900 mg of NMN for 60 days.
What those trials cannot tell you is anything past a few months. Long-term safety in people has not been studied. People with cancer, anyone pregnant or breastfeeding, and anyone on prescription drugs should talk to a doctor before trying NAD+ precursors. Those groups were not in the trials.
Niacin, another form of vitamin B3, also raises NAD+. High-dose niacin can make the skin flush. NR did not cause flushing in the Conze trial. Do not treat high-dose niacin as a cheap substitute without a doctor's input.
The label problem: some products do not contain it
A 2024 study in GeroScience bought NMN and urolithin A supplements online and in pharmacies and measured the active ingredient. Results ranged from 28.6% above the label to 100% below it. A result of 100% below means the product had none of the ingredient. In the US, the FDA does not check that a supplement contains what the label says before it is sold.
Look for third-party testing that names the lab and the measured amount, not a bare "lab tested" line. Prefer a certificate of analysis for the lot in your hand. Very cheap NMN is a reason to slow down, because the 2024 test found products with none.
Who might consider it, and who should skip it
Who Might Like This
- ✓Adults who understand the evidence is early, want the blood-level effect, and have talked with a doctor.
Who Should Consider Alternatives
- ×Pregnancy, breastfeeding, cancer or a cancer history, prescription medicines, and children or teens. Ask a doctor first, or skip it.
- ×Anyone expecting weight loss, reversed aging, or better blood sugar. The larger trials did not show those.
Sources
- Martens et al., Nature Communications, 2018. doi:10.1038/s41467-018-03421-7
- Dollerup et al., American Journal of Clinical Nutrition, 2018. doi:10.1093/ajcn/nqy132
- Remie et al., American Journal of Clinical Nutrition, 2020. doi:10.1093/ajcn/nqaa072
- Yoshino et al., Science, 2021. doi:10.1126/science.abe9985
- Yi et al., GeroScience, 2023. doi:10.1007/s11357-022-00705-1
- Conze, Brenner, and Kruger, Scientific Reports, 2019.
- Label test of NMN and urolithin A, GeroScience, 2024. doi:10.1007/s11357-024-01257-2
- FDA letter, Sept 29, 2025, docket FDA-2023-P-0872. NMN is not excluded from the dietary-supplement definition.
How we checked
FDA letter dated September 29, 2025, docket FDA-2023-P-0872, read November 9, 2026. It concludes NMN is not excluded from the dietary-supplement definition under section 201(ff)(3)(B).
Trial figures are from the papers named in the table: Martens 2018, Dollerup 2018, Remie 2020, Yoshino 2021, Yi 2023, and Conze 2019.
The 2024 GeroScience label test (doi:10.1007/s11357-024-01257-2) reported NMN and urolithin A content from 28.6% above the label to 100% below it.
Frequently Asked Questions
They raise NAD+ in the blood. That is well shown. Whether that improves health is unclear. Larger NR trials found no change in insulin sensitivity or body composition. Two small NMN trials found modest benefits.
No human trial in this review compared them head to head on health outcomes. Both raise NAD+. Pick a product with a named lab result, not a favorite molecule.
In trials lasting up to about 12 weeks, side effects were mild and no more common than with placebo. Long-term safety has not been studied.
FDA's September 29, 2025 letter says NMN is not excluded from the definition of a dietary supplement. New-dietary-ingredient requirements still apply.
Trials used 250–900 mg of NMN a day and 100–2,000 mg of NR a day. That is what was studied, not a dose to copy. Ask a doctor.
The trials on this page tested oral supplements only, so they cannot answer that.
This is not medical advice and not a treatment for any disease. The trials below used oral pills, not IV drips. Evident does not sell NAD+ products and uses no affiliate links.