longevitywatch

What is the controversy surrounding NAD+?

NAD+ supplements raise your NAD+ levels, but whether that translates into any health benefit has not been proven, and in the context of cancer (treatment) there are serious safety questions. Discuss it with your doctor if you have a cancer diagnosis or are undergoing chemotherapy.

NAD+ supplements (such as NMN and NR) demonstrably raise NAD+ levels in multiple tissues in humans, and are described in studies as safe and well tolerated. But higher NAD+ levels are not a goal in themselves: the real question is whether you actually notice any benefit. And that is where the problem lies.

When it comes to measurable health benefits in ageing, the evidence so far is unclear. Studies are small, doses and study durations vary widely, and large independent trials are still lacking. Whether NAD+ supplementation genuinely improves heart function, metabolism or other organ functions in ageing people has not been demonstrated.

A serious safety signal comes from cancer research. In laboratory studies and mouse studies, NMN (and to a lesser extent NAM) helped pancreatic cancer cells survive and made them more resistant to common chemotherapy regimens. This effect appeared across multiple mouse models. Broader indications suggest that other cancer types, such as acute myeloid leukaemia, also rely heavily on NAD+ production. Raising NAD+ in people with cancer could therefore fuel that process. There is no evidence that this also occurs in humans, but the signal is serious enough not to ignore.

On top of that, there are fundamental gaps in knowledge. The role of the gut microbiome in converting NAD+ precursors, the existence of separate NAD+ pools in different parts of the cell, and exactly how NAD+ is broken down: all of this is still insufficiently understood. Without that knowledge, it is difficult to apply supplementation in a targeted and safe way.

Finally, there is the issue of conflicts of interest. Several authors of widely cited review articles on NAD+ have financial ties to companies that manufacture or sell these supplements. This makes independent interpretation of the available research findings more difficult.

The evidence
5 studies

Claims based on PMID 37068054, 40926126, 39026037, 41724424 and 42514364. Cancer data come from laboratory and mouse research, not from human studies.

Last checked: September 2026 · how this was judged
Related answers

Does NAD+ cause weight gain?

There is no scientific evidence that NAD+ supplements such as NMN or NR cause weight gain. Animal research even suggests the opposite, but this has not yet been confirmed in humans.

No · Preliminary evidence

Are NAD+ supplements (NMN/NR) worth it?

NMN and NR demonstrably raise NAD+ in your blood and appear to be safe, but whether you will actually notice any difference in muscle strength, heart function or memory? That is far from proven in humans. Note too: NR is authorised as a supplement in the EU, NMN is not (yet).

Preliminary evidence

Which supplements or medications are best not combined with NAD+?

The combination of NAD+ supplements (particularly nicotinamide) with platinum-based chemotherapy is the most concrete reason for caution; for other interactions the indications are preliminary but worth discussing with your doctor if you are using multiple substances.

Preliminary evidence

Does a NAD+ infusion do something that an NMN pill does not?

There is no study that directly compares a NAD+ infusion with an oral NMN pill, so any advantage of the infusion has not been demonstrated. If you want to start NAD+ support, oral NMN is the only option with some clinical backing.

Preliminary evidence

What is NAD+ and what does it do in your body?

NAD+ is an indispensable molecule for energy, DNA repair and cell health, but the question of whether you should actively raise those levels for better health has not yet been answered for humans.

What does NAD+ do for your brain?

NAD+ is biologically crucial for your brain and declines with age, but whether supplementation via NMN or other means genuinely protects humans has not yet been convincingly demonstrated. Wait for the results of larger clinical studies before drawing firm conclusions.

Related research
23 Sep
Grip strength tests gene therapy for aging
23 Sep
Novo Nordisk bets on life beyond GLP-1 drugs
22 Sep
Fasting improves symptoms in Huntington’s patients
Don't see your question?
Ask it and we'll look it up for you.
Ask a question
Newsletter

Stay in the loop

Twice a week, the most important longevity research in your inbox.