NMN, NAD+ and Resveratrol: What Is the Evidence?

The longevity supplement market rests on a simple story. A molecule called NAD+ falls with age. Sirtuins are a family of proteins linked to longevity in yeast and mice, and they need NAD+ to work. So the pitch follows. Raise NAD+ with a precursor such as NMN or nicotinamide riboside. Or switch sirtuins on directly with resveratrol. Either way, you should slow aging.

It is a clean story, and there is real science underneath it. This page asks a narrower and more useful question: what has actually been shown in people?

This is the single most important fact in the field. It is rarely stated plainly.

Not one published randomised trial of NMN or nicotinamide riboside has measured mortality, disease incidence, or any hard clinical endpoint. Every published trial has measured surrogate markers instead — blood or muscle NAD+ levels, insulin sensitivity, blood lipids, blood pressure, mitochondrial function. Some measured short-term performance proxies.

A 2023 review in Science Advances read all 25 published human trials of nicotinamide riboside. Studies ran from 2 hours to 6 months. Treatment groups held about 3 to 40 people. Its verdict is blunt. Oral nicotinamide riboside "has displayed few clinically relevant effects." And the field tends to overstate its own results.

What those trials found is mixed at best:

• The best-powered nicotinamide riboside metabolic trial ran 12 weeks in 40 participants at 2,000 mg/day. It reported that insulin sensitivity, glucose production, disposal and oxidation were "not improved".
• A 21-day crossover trial in 12 older men raised the muscle NAD+ metabolome "without altering mitochondrial bioenergetics". The number went up. The thing the number is meant to stand for did not change.
• A 2018 crossover trial raised NAD+. Blood pressure fell about 3.9 mmHg, and arteries stiffened less. Neither change was statistically significant once the maths allowed for multiple comparisons. The authors called for a bigger trial.
• A 2021 Science trial reported a benefit and drew wide coverage. It was then formally challenged in the same journal. The grounds were that the two groups differed substantially at baseline. The two groups differed sharply in liver fat. It was 6.3% in the 13 women given NMN, and 14.8% in the 12 on placebo. The critic wrote that "this was not an effectively randomized trial." The authors replied, and the dispute stands on the record.

Raising a biomarker is not the same as improving health. That distinction is the whole gap between this field's marketing and its evidence.

Resveratrol is the compound in red wine. It was reported to activate sirtuins and extend life in model organisms. That set off enormous excitement, a biotech company, and a major pharmaceutical acquisition.

Other laboratories then reported something else. The activation appeared to be an artefact of the assay used, rather than a direct effect on the enzyme. The dispute ran for years in the literature. The drug program built on the idea was ultimately discontinued.

Sirtuin biology itself remains a serious, active research field. The scientists involved have made genuine contributions to it. What did not survive was the specific, simple claim: that swallowing resveratrol activates sirtuins, and thereby extends human life.

You will meet prominent scientists who advocate these compounds. Some hold commercial interests in them. That combination is not automatically disqualifying, and many productive researchers commercialise their work. But it is a reason to check claims against the primary literature, rather than against a confident summary.

The useful test is not who is saying it. The test is this. Has this been tested in people, with a randomised design, measuring something that matters — and what happened? For NMN, nicotinamide riboside and resveratrol, the answer to the first part is "only partially". To the second, it is "not yet".

This is why a cancer charity is writing about longevity supplements at all.

Tell your oncology team what you take. Bring the actual bottles to the appointment, not a list from memory. Supplements are not inert. Some interact with cancer drugs. And your team cannot account for what they do not know about.

There are specific open questions about antioxidants during treatment. Radiotherapy and some chemotherapies work partly by causing oxidative damage to cancer cells. Whether high-dose antioxidant supplements blunt that is not fully resolved. That is exactly why it is a conversation to have before you start, rather than after.

One animal finding is worth knowing about, stated carefully. A 2023 study built a new way to image how cells take up nicotinamide riboside. It then used that tool in mice with triple-negative breast cancer. The authors report a significant rise in cancer prevalence, and in spread to the brain. What the study did not show is that NR causes cancer. The design used implanted cancer cells. So "prevalence" here means how often those cells took hold. It does not mean new cancers formed. And it was done in mice, not people.

We are not telling you that NAD+ boosters cause or worsen cancer. Nobody has shown that. We are telling you three things. The evidence in this area is thin in both directions. A signal exists in animals pointing the wrong way. And "unstudied" is a poor reason for confidence when you are already being treated for cancer.

The FDA's position on NMN has moved, and the movement was widely reported as a reversal. The agency once treated NMN as excluded from the dietary supplement definition. It no longer does. Its public list of new dietary ingredient notifications now records two NMN submissions that FDA has filed and answered, with response dates in January and April 2026.

Carry away what that does and does not mean. A notification is a filing by the company. In it the firm argues its ingredient can be expected to be safe as labelled. FDA answering one is not a verdict that it works. Legal to sell and shown to work are different things.

These compounds might turn out to do something. The biology is not nonsense, and the people working on it are not frauds. But here is the human evidence as of now. Small, short trials that measured markers rather than outcomes. At least one formally disputed result. And no demonstration that anyone lives longer or better.

If you are spending money on this, spend it knowing that is what you are buying. And if you are in cancer treatment, have the conversation with your team first.

Every figure above comes from the trial publication or regulator named beside it. None comes from a summary of one. Where the honest answer is that nobody knows, this page says so rather than filling the gap.

• PubMed — What is really known about the effects of nicotinamide riboside supplementation in humans (Science Advances, 2023)
• PubMed — A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects
• PubMed — Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome (Cell Reports, 2019)
• PubMed — Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults (Nature Communications, 2018)
• PubMed — Comment on "Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women" (Science, 2021)
• PubMed — Response to that comment (Science, 2021)
• PubMed — A bioluminescent probe for nicotinamide riboside uptake, including the triple-negative breast cancer mouse model (Biosensors and Bioelectronics, 2023)
• FDA — Submitted 75-Day Premarket Notifications for New Dietary Ingredients
• NIH Office of Dietary Supplements — Dietary Supplements: What You Need to Know
• National Cancer Institute — Complementary and Alternative Medicine

Educational information, not medical advice. Do not start, stop or change any medication or supplement because of a web page — including this one. If you are on cancer treatment, tell your oncology team about everything you take, including supplements. Spotted an error? Please email corrections@cancerexplained.org or use /corrections.