NAD+ and NMN supplements: what they are, what human trials show and where they're legal

What are NAD+, NMN and NR?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme, a helper molecule for enzymes. Every cell has it and needs it to get energy from food. Enzymes involved in repairing DNA also depend on it. Your body makes NAD+ itself, from vitamin B3 and the amino acid tryptophan.

Supplements usually contain not NAD+ but its precursors, which cells turn into NAD+:

• NMN, nicotinamide mononucleotide;
• NR, nicotinamide riboside, often labelled “nicotinamide riboside chloride”;
• nicotinamide and niacin, the classic, cheap and long-studied forms of vitamin B3.

EFSA describes NMN as a source of nicotinamide, in other words a form of vitamin B3. How much NAD+ from capsules of NAD+ itself reaches your cells is unknown: clinical trials mostly use NMN and NR.

Why NMN is marketed as an anti-ageing supplement

In animal studies, NMN raised NAD levels, and the animals stayed healthy for longer and lived longer. That’s the basis of the anti-ageing marketing. But animal results don’t transfer neatly to people: human biology differs in many ways, and human trials last weeks rather than years.

NMN benefits: what human trials show

Points to weigh:

• the main proven effect is higher blood NAD, which is a lab value, not a health outcome;
• the trials are small and short, from 2 to 12 weeks;
• in the 2023 trial, some authors were employees of the chemical companies Abinopharm and ABA Chemicals;
• its “biological age” was worked out with an online calculator from blood tests, an estimate rather than a measure of ageing;
• there’s no evidence in people for longer life, protected memory or disease prevention.

The authors of the 2025 meta-analysis concluded that current evidence doesn’t support NMN or NR for preserving muscle in people over 60.

Is NMN legal in the UK, EU and US?

Until the European Commission issues an authorisation, NMN can’t legally be sold as a food in the EU. After EFSA’s positive opinion, that decision may come soon, so check the current rules where you live before ordering.

How much NMN or NR to take

There’s no official dose: neither NMN nor NR is an essential nutrient, since your body also makes NAD+ from ordinary vitamin B3. Trials and regulators give some reference points:

In the 2023 trial NMN was taken once a day. Blood NAD rose even at 300 mg, but more at 600 and 900 mg. Higher doses cost more and have less safety data, so it’s sensible to stay at or below 300 mg a day.

Here are those limits side by side:

NMN is often sold in “longevity” blends with resveratrol. We found no convincing evidence that such combinations help people.

Safety: who shouldn’t take NMN or NR

In the 2023 trial, NMN was well tolerated over 60 days with no serious side effects, even at 900 mg a day. There’s no data on use beyond a few months.

EFSA looked at NMN in more detail in 2026:

• 300 mg of NMN provides about 110 mg of nicotinamide, roughly five times the adult reference intake for niacin but below the 900 mg upper limit for nicotinamide;
• at high doses, rats showed changes in reproductive organs, but EFSA judged the safety margin at 300 mg a day to be enough;
• its conclusion applies to adults only, excluding pregnant and breastfeeding women.

Don’t take NMN or NR if:

• you’re pregnant or breastfeeding: NMN hasn’t been assessed for this, and while the EU allows NR at up to 230 mg a day, it has no proven benefit;
• it’s for a child or teenager;
• you’re being treated for cancer, unless your oncologist agrees: there’s no safety data.

If you take medicines or have long-term liver or kidney disease, talk to your GP first. Nicotinamide adds up across products, so check how much vitamin B3 is already in your B complex or multivitamin.

Price vs evidence

With NMN and NR you pay for one proven result: higher NAD in your blood. Before buying, work out the cost of a daily dose with our cost-per-day calculator and weigh it against what you’d actually get.

If you have a specific goal, there are better-studied options:

• strength and muscle: creatine monohydrate alongside resistance training;
• constant tiredness: get tested first for iron, vitamin B12 and thyroid function;
• memory: see the options in our brain and memory section.

Not sure what you need? Try our vitamin check.

How to choose NMN or NR on iHerb

1. Check it’s legal where you live: NR is authorised in the UK and EU; NMN isn’t yet.
2. Check the dose: no more than 300 mg NR chloride a day (the EU limit) or 300 mg NMN a day (EFSA’s safety assessment).
3. Choose a single-ingredient product rather than a “longevity” blend with resveratrol and herbs.
4. Add up your total nicotinamide, including any multivitamin.
5. Prefer products with independent quality testing (USP, NSF or similar seals).
6. Review honestly after 2–3 months. If nothing has changed, there’s no point carrying on.