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

The longevity supplement market rests on a straightforward story. A molecule called NAD+ declines with age. Sirtuins, a family of proteins associated with longevity in yeast and mice, need NAD+ to work. Therefore: raise NAD+ with a precursor such as NMN or nicotinamide riboside, or activate sirtuins directly with resveratrol, and you should slow aging.

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

This is the single most important fact in the field, and 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 — blood or muscle NAD+ levels, insulin sensitivity, blood lipids, blood pressure, mitochondrial function — or short-term performance proxies.

The durations run from five hours to twelve weeks. The cohorts number in the tens. The largest published NMN randomised trial had 108 participants over 12 weeks.

What those trials found is mixed at best:

• The best-powered nicotinamide riboside metabolic trial (40 participants, 12 weeks, 2,000 mg/day) reported that insulin sensitivity, glucose production, disposal and oxidation were "not improved".
• A 21-day trial raised NAD+ levels "without altering mitochondrial bioenergetics" — the number went up; the thing the number is supposed to represent did not change.
• A 2018 trial raised NAD+ but found blood pressure and arterial stiffness changes not statistically significant.
• A 2024 trial of NMN missed its primary endpoint.
• A widely publicised 2021 Science trial reporting benefit was formally challenged in the same journal, on the grounds that the two groups differed substantially at baseline: 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 entire gap between this field's marketing and its evidence.

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

Other laboratories then reported that 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 programme built on the idea was ultimately discontinued.

Sirtuin biology itself remains a serious, active research field, and 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 encounter prominent scientists advocating these compounds, sometimes while holding commercial interests in them. That combination is not automatically disqualifying — 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. It is: 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" and to the second, "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 rather than 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, which is precisely why it is a conversation to have before starting rather than after.

One animal finding is worth knowing about, stated carefully. A study published in 2023 reported that mice given nicotinamide riboside before triple-negative breast cancer cells were implanted showed a significant increase in tumours establishing, and in spread to the brain. What that study did not show is that NR causes cancer — the design used implanted human cancer cells, so "prevalence" means how often injected cells took hold, not whether new cancers formed. The senior author has said plainly: "This study was performed in small animal models" and "these findings have not been studied in humans."

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

The FDA's position on NMN has moved. In October 2022 the agency said NMN was excluded from the dietary supplement definition. Citizen petitions followed, and in September 2025 the FDA said it "has reconsidered and changed its interpretation", concluding that "NMN is not excluded from the definition of dietary supplement". In December 2025 it formally set aside the 2022 letters.

One line from the FDA is worth carrying away, because it applies to every supplement on the shelf: accepting a notification "is a procedural matter" and "does not constitute a finding by FDA" that the ingredient is safe or effective. Being legal to sell and being shown to work are entirely 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 as of now the human evidence consists of small, short trials measuring 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 is from the trial publication or regulator named beside it, not from a summary of one. Where the honest answer is that nobody knows, this page says so rather than filling the gap.

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 [email protected] or use /corrections.