What are the benefits of NAD+, and what does the evidence show?

This guide takes the uses commonly claimed for NAD+ and sets each against what human research has shown, using primary sources.

We report what studies found and say plainly where evidence is missing; we make no health claims of our own, and we do not say NAD+ injections work or that they do not.

What are NAD+ benefits claimed to be?

The claims we looked at fall into a handful of groups, and for injected NAD+ the evidence for every one of them is unproven.

The table states each as a claim, followed by its evidence status and a rating on a four-point scale (unproven, early, mixed, established) that follows the strength of the sources, not our opinion.

Each rating above is for the use named; evidence on oral precursors is shown only for context, because it does not carry over to injections.

What does human research on NAD+ show?

It shows the biology and some chemistry in small groups, but no outcomes trials of intravenous or intramuscular NAD+ for ageing or wellness ⁴.

The 2026 systematic review identified 113 eligible studies, of which 33 were in humans (28 randomised) and 80 in rodents ⁴.

It concluded that NAD+ augmentation “shows clear biological activity” but that clinical effectiveness for ageing or wellness outcomes “remains inconclusive” ⁴.

Oral precursor trials, which are a different product, mostly report mixed or null health outcomes ⁴.

Our guide to NMN vs NAD+ sets those trials out.

Do NAD+ injections work?

We found no human evidence showing that NAD+ injections improve health outcomes, and no evidence showing that they do not, so the question is open.

The systematic review found no eligible outcomes trials of intravenous or intramuscular NAD+ for ageing or wellness ⁴.

Our own PubMed searches on 11 November 2026 found no human studies of subcutaneous NAD+.

A 2026 narrative review concludes that “current evidence regarding IV NAD+ therapy remains preliminary and insufficient to support routine clinical or wellness use” ⁷.

The systematic review calls for larger, well-designed randomised trials with longer follow-up, “particularly for parenteral approaches” ⁴.

Studies of NAD+ chemistry are not outcome trials: in the 11-man pilot, infused NAD+ was rapidly and completely removed from plasma for at least the first two hours, which is a result about where it goes, not about any benefit ¹⁷.

The ASA’s expert advice is that it is “unlikely to be acceptable to rely on studies which examine regular supplementation and extrapolate it to a one-off IVNT infusion” ¹⁸.

Our guide to side effects and safety covers what has been reported about harms.

Does NAD+ help with weight loss?

We found no trials of injected NAD+ for weight loss, and a meta-analysis of related vitamin B3 precursors found no significant effect on body weight.

That meta-analysis pooled 22 arms and 5,144 participants taking nicotinic acid or nicotinamide, and reported no significant effect on body weight and leptin ⁹.

The same abstract reports a very small pooled difference in BMI of -0.19 kg/m2 ⁹.

Those are oral vitamin B3 forms, not NAD+ injections, so they do not answer the question directly.

On advertising, an ASA ruling of 20 December 2023 (A19-549582) on IV vitamin drips, which does not concern NAD+, told the company not to claim that drips could “help to speed up metabolism and lose weight” without adequate evidence ¹⁹.

Why are before-and-after photos and testimonials weak evidence?

Photos and testimonials show what happened to one person at two moments; they cannot show what would have happened without the injection.

Controlled trials exist to separate an intervention’s effect from other explanations, and the human evidence on injected NAD+ is mostly small, uncontrolled studies, observational investigations and isolated case reports ⁷.

The one NAD+-labelled long COVID pilot we found gave skin patches together with low-dose naltrexone to 36 people with no control group, which means the effect of NAD+ cannot be separated from the second drug or from natural recovery ¹⁰.

UK advertising rules ask for more: objective claims must be backed by evidence, where relevant including trials on people ²⁰.

In the December 2023 IV drip rulings, the ASA told the companies not to claim health benefits until they held evidence in normally healthy humans adequate to support them ¹⁹.

How are clinics allowed to advertise NAD+ in the UK?

Prescription-only medicines may not be advertised to the public, and medicinal claims may be made only for a licensed product, so advertising of NAD+ injections is tightly limited.

Whether a given NAD+ product is a prescription-only medicine is not settled in any public MHRA statement we could find, so these rules apply if it is one.

In April 2020 the ASA upheld a complaint about Instagram posts promoting a 250 mg NAD+ IV drip, finding they implied medicinal claims for an unlicensed product ¹¹.

In February 2026 it upheld a complaint about NAD+ skin patches, finding claims about energy, focus, memory and ageing were not substantiated ²³.

The Observer reported in February 2025 that an MHRA spokesperson said anyone making medicinal claims about NAD+, “including using NAD+ to help with addiction”, is in breach of its regulations ²⁴.

Our guide to the UK legal and advertising position goes into the detail.

Who may want to speak to a doctor first?

Anyone considering NAD+ may want to speak to their GP first, particularly if they have a health condition, take prescribed medicines or are thinking of repeated courses.

• Your health history. The NMC says prescribers have a professional responsibility to supply medicines only where they have enough knowledge of your health and your full medical and prescribing history ²⁵.
• Instead of advised care. CAP rules say: “Marketers must not discourage essential treatment for conditions for which medical supervision should be sought” ²⁰.
• Repeated use. A 2026 review states that long-term safety data are lacking ⁷.
• Alcohol or drug dependence. A GP or local NHS drug and alcohol service can talk through medically supervised options; we found no controlled human trials of NAD+ infusion for withdrawal ⁷.

If you decide to look further, our guide on how to check a clinic sets out what to ask.

This page is general information, not medical advice. Speak to your GP or a registered prescriber before deciding anything about NAD+, and read our medical disclaimer.

It was drafted with AI assistance from a fact-pack of primary sources by the NAD Injections editorial team and has not been clinically reviewed.