NMN in the UK: legal status and evidence

Nicotinamide mononucleotide is not an authorised novel food in Great Britain. The Food Standards Agency's public record for application RP-2116 lists β-nicotinamide mononucleotide, applicant Effepharm (Shanghai) Ltd., status in progress, phase risk assessment. Risk assessment is not authorisation. The steps still marked as not reached are risk management and authorisation. A novel food has to be authorised before it is placed on the market in England, Scotland and Wales.

What the register does and does not say

The record's own summary is an application for approval of β-nicotinamide mononucleotide as a novel food ingredient. Scientific information and the FSA safety assessment were marked not specified. An empty assessment field is not a quiet approval. Northern Ireland's novel-food route is not this Great Britain register.

Nicotinamide riboside chloride is different. The FSA authorised-novel-food record NOVEL-96 lists it as authorised in England, Scotland and Wales, for food supplements, at up to 300 mg a day for the general adult population excluding pregnant and lactating women, and 230 mg a day for pregnant and lactating women. The label name has to be 'nicotinamide riboside chloride'. That authorisation is not an authorisation of NMN, and it is not a claim that either ingredient extends life. Health claims still have to sit on the Great Britain nutrition and health claims register. There is no authorised anti-ageing claim for these substances.

Advertising is an ASA and CAP question as well as a novel-food question. A website aimed at UK readers that tells people an unauthorised novel food will treat aging is a regulatory problem, not a wellness tip. The MHRA is relevant if the product is sold as a medicine. We are describing the law as the FSA register shows it. We are not offering a way around it.

What the human trials show

NMN is nicotinamide mononucleotide. Cells can use it on the way to making NAD, a molecule used in ordinary energy chemistry. That sentence is biochemistry. It is not a result. The human trials measured markers and a few functions. They did not measure whether anyone lives longer.

Yoshino and colleagues, published in Science in 2021, randomised 25 postmenopausal women with prediabetes who were overweight or obese. Thirteen took 250 mg of NMN a day and twelve took placebo, for 10 weeks, double blind. Muscle insulin sensitivity, measured with a clamp, was about 25% higher after NMN than before it. The placebo group did not show that change. Insulin signalling in muscle (AKT and mTOR phosphorylation) increased after NMN. Body fat, blood pressure, and blood lipids did not change in the way a weight-loss advert would want. The paper reports no adverse events and no abnormal standard blood tests in either group. Twenty-five women, ten weeks, one research centre: this is an early metabolic finding in a narrow group. It is not evidence that NMN treats diabetes, and the participants already had prediabetes, so the result does not automatically apply to a healthy reader.

Yi and colleagues, 2023, randomised 80 healthy middle-aged adults to placebo or to 300 mg, 600 mg or 900 mg of NMN once a day for 60 days. Everyone finished. Blood NAD was higher at day 30 and day 60 in every NMN group than in placebo, and the 600 mg and 900 mg groups were highest. Distance on a six-minute walk increased more than placebo at day 30 and day 60. A HOMA-IR insulin-resistance figure was not different from placebo at day 60. The authors said they saw no safety problem on the adverse events and the laboratory measures they tracked, up to 900 mg a day for 60 days. They also reported a blood 'biological age' calculator that moved in the placebo group and not in the NMN groups. That calculator is not a clock you can read at home, and a 60-day difference on it is not evidence that the participants became younger. The trial's own background sentence mentions animal lifespan. The human trial did not measure lifespan.

Put the two trials together and the established part is narrow. Oral NMN can raise a blood NAD measure over weeks, at the amounts Yi used, in middle-aged adults who were healthy enough to join that trial. A single small trial found a muscle insulin-sensitivity change in postmenopausal women with prediabetes at 250 mg a day. Walking distance moved in Yi's trial. What is not shown is longer life, a treatment for diabetes, a change in body composition, or safety over years. EFSA's 2026 opinion, below, is a safety opinion on one specified ingredient. It is not a verdict that NMN 'works'.

Amounts used in those studies

Yoshino used 250 mg a day for 10 weeks. Yi used 300, 600 or 900 mg a day for 60 days, and the authors said physical-performance and NAD measures looked strongest at 600 mg rather than at 900 mg. EFSA assessed one chemically synthesised β-NMN, at least 99% pure, at up to 300 mg a day as a proposed food-supplement use in adults who are not pregnant and not lactating. The panel said 300 mg corresponds to about 109.7 mg of nicotinamide, below the 900 mg a day upper level it cites for nicotinamide, and about five times a population reference intake for niacin. A rat study found effects on reproductive organs, with a no-observed-adverse-effect level of 400 mg per kilogram of body weight a day. Those figures describe a safety file and trial protocols. They are not a recommended intake. There is no NHS or NIH recommended intake for NMN, because it is not an essential vitamin in its own right. The body can make it from nicotinamide.

The European safety opinion is not a British authorisation

On 11 May 2026 EFSA published an opinion on one chemically synthesised β-NMN, purity at least 99%, proposed for food supplements at up to 300 mg a day in adults who are not pregnant and not lactating. The panel said that ingredient was safe under those proposed conditions and was a bioavailable source of nicotinamide. A scientific opinion is an input to the European Commission. It is not the Commission's authorisation, and it is not the FSA's authorisation. RP-2116 was still at risk assessment. Anyone who says 'EFSA approved NMN for sale in the UK' is ahead of both documents.

Side effects in the cited sources

Yoshino reported no adverse events at 250 mg for 10 weeks in 25 women. Yi reported no safety signal at up to 900 mg for 60 days in 80 adults, on the measures in that paper. EFSA described reproductive-organ effects in a 90-day rat study and kept pregnant and lactating women out of the proposed use. That is the safety file. It is not a reassurance about years of use, and it is not a product recommendation. The longer side-effect note is the UK side-effects page.

If you are pregnant, trying to conceive, being treated for cancer, or you already take a prescribed product, talk to a GP or a pharmacist. Call 999 in an emergency and NHS 111 when you need urgent advice that is not life-threatening. Do not buy an unauthorised novel food because a podcast said the trials were finished. The trials are early, and the authorisation is not.