NAD+ supplements vs injections vs drips: a UK guide

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme every cell uses to turn food into energy and to run enzymes involved in DNA repair. Levels fall with age in many tissues, which is why it is sold in so many forms: capsules of its building blocks, capsules of NAD+ itself, skin patches, injections and intravenous drips at wellness clinics. These routes are not interchangeable, and the evidence for each is very different.

The short answer: capsules of nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN) reliably raise NAD+ in the blood. Whether that makes people feel or function better is a separate question, and so far human trials mostly say no, or not yet. Injections and drips have no outcome trials at all, and the closest comparison suggests IV NAD+ is unpleasant to receive. In Great Britain, the only one of these with an authorised food supplement ingredient is nicotinamide riboside chloride.

Key facts

• What NAD+ is: a dinucleotide made of two nucleotides joined together. It is not a peptide.
• Oral doses studied: NR from 100 to 1,000 mg a day in most trials, NMN from 250 to 2,000 mg a day.
• UK status: nicotinamide riboside chloride is an authorised novel food for adult food supplements at up to 300 mg a day. NMN is not authorised. Injections and drips are not food supplements.
• Main safety point: in a clinic records study, everyone given IV NAD+ had moderate to severe symptoms during the drip. Oral NR and NMN have been well tolerated over weeks to months.

What the evidence says

Grades used here: Strong (consistent results from several good-quality human trials), Moderate (good trials, but few or with mixed results), Limited (small or low-quality human studies, or mixed results), Insufficient (too little human research to judge) and Evidence of harm.

Oral NR and NMN raise blood NAD+: Strong

The first trial to compare NAD+ precursors directly in people randomised 65 healthy adults to 1,000 mg a day of NR, 1,000 mg a day of NMN, 500 mg a day of nicotinamide or placebo for 14 days. It was open-label and run by Nestlé Research scientists. NR and NMN each roughly doubled whole-blood NAD+, by similar amounts. Nicotinamide produced only a short-lived rise in the hours after a dose and no lasting increase.

Earlier work fits. In an eight-week randomised, placebo-controlled trial in healthy overweight adults, funded by the maker of an NR ingredient, 100 mg, 300 mg and 1,000 mg of NR a day raised whole-blood NAD+ by about 22%, 51% and 142% within two weeks. That matters in the UK, where the authorised maximum is 300 mg a day: at that dose the rise was about half, not a doubling. A six-week crossover trial in healthy middle-aged and older adults found NR well tolerated and raised NAD+, and a 24-week trial in adults aged 65 and over found 1,250 mg of NMN a day kept blood NAD+ raised throughout. A 2026 systematic review of 33 human intervention studies, 28 of them randomised, concluded that oral NR and NMN consistently engage their target.

Blood sugar, insulin and cholesterol: Limited

The most cited positive result is a 10-week randomised, placebo-controlled trial in 25 postmenopausal women with prediabetes and overweight or obesity. In the 13 women given 250 mg of NMN a day, muscle insulin sensitivity rose by about 25% from the start of the trial, while it did not change in the 12 given placebo. Pooled results have not shown a broad metabolic effect. A meta-analysis of eight NMN trials with 342 adults, at 250 to 2,000 mg a day, found no significant benefit for fasting glucose, insulin, HbA1c, insulin resistance or blood fats. A 2026 meta-analysis of 15 NMN trials lasting 14 days to 24 weeks found no effect on body weight, BMI, fasting glucose, HbA1c, blood fats or systolic blood pressure, and a small fall in diastolic blood pressure.

Energy, fitness and ageing: Limited

Higher blood NAD+ has not reliably translated into outcomes people notice. The 2026 systematic review found that effects on functional, metabolic, vascular and other healthspan measures in humans were heterogeneous and often null, even though rodent studies were far more positive. In the 24-week trial in older adults, NMN raised NAD+ but did not improve the main outcome, hearing, or measures of physical performance. Our NMN evidence page covers the NMN trials in more detail.

IV NAD+ drips: Insufficient

No randomised trial has shown that NAD+ infusions improve how people feel or function. The 2026 systematic review found no eligible outcome trials of intravenous or intramuscular NAD+ for anti-ageing or wellness. What exists is pharmacology. In a 2019 pilot study of a six-hour NAD+ infusion, plasma NAD+ and its breakdown products did not change at all for the first two hours, which the authors interpreted as NAD+ being rapidly and completely removed from the blood.

The newest comparison is a retrospective review of records from a US wellness clinic chain. Six clients had 500 mg of IV NAD+ and eight had 500 mg of IV NR, once a day for four days, with 30 days of follow-up. All six NAD+ clients reported moderate to severe abdominal cramping, diarrhoea, nausea, vomiting, a raised heart rate and chest pressure during the infusions, and the drips had to run slower: 97 minutes on average for NAD+ against 37 minutes for NR. Symptoms stopped when the infusions ended, and liver, kidney, thyroid and inflammation markers did not change significantly. Blood NAD+ could not be assessed because too few samples were taken. There was no placebo group, the authors worked for the clinic chain that funded the study, and the NR was donated by its manufacturer.

NAD+ injections: Insufficient

Injections into the skin or muscle are widely offered, but there is no published randomised trial of them for any health outcome. Laboratory work in human cells shows that outside the cell, NAD+ and NMN are broken down into smaller precursors before cells take them up, which raises the question of what an injection adds over taking a precursor by mouth.

Swallowed NAD+, liposomal NAD+ and patches: Insufficient

Cells cannot take up NAD+ intact; it has to be broken down outside the cell first. Products that contain NAD+ itself, including "liposomal" versions and skin patches, have no published human trials showing they raise blood NAD+ as well as NR or NMN, or that they change any outcome.

Dosing and safety

Oral NR has been well tolerated in trials at 100 to 1,000 mg a day, and a four-week safety trial in 20 people with Parkinson's disease used 1,500 mg twice a day with no moderate or severe adverse events. NMN trials have used 250 to 2,000 mg a day for up to 24 weeks, and the 2026 meta-analysis found no increase in adverse events or liver enzymes. The honest limit is that there are no multi-year trials of either.

IV NAD+ is different. In the clinic records study, everyone who received it had moderate to severe symptoms during the drip. Any injection or infusion also carries the usual risks of a needle, including bruising, infection and reactions at the site. If you have chest pain, severe breathlessness or feel faint during or after an infusion, call 999. For urgent advice that is not an emergency, call NHS 111.

Interactions

Interaction data specific to NR and NMN are sparse. A 2024 meta-analysis of 45 trials with 9,256 people found that NAD+ precursors as a group raised fasting glucose slightly, by about 2 mg/dL, and HbA1c by about 0.1 percentage points, and lowered C-reactive protein, with nicotinic acid raising glucose and HbA1c more than nicotinamide. If you take medicines for diabetes, speak to your GP or pharmacist before starting any NAD+ product, and tell any clinic offering injections about every medicine you take.

UK regulatory status

Food Standards Agency. Nicotinamide riboside chloride is an authorised novel food in England, Scotland and Wales, listed as NOVEL-96. It may be used in food supplements at up to 300 mg a day for adults, excluding pregnant and breastfeeding women, and up to 230 mg a day for pregnant and breastfeeding women, and must be labelled "nicotinamide riboside chloride". This follows a 2019 EFSA opinion that judged it safe at those levels for those groups. NMN is not authorised: an application for beta-nicotinamide mononucleotide is still in progress at the FSA, at the risk-assessment stage.

Medicines law. NAD+ injections and drips are not food supplements. Under the Human Medicines Regulations 2012, a substance administered to restore, correct or modify a physiological function through a pharmacological, immunological or metabolic action is a medicinal product. An unlicensed medicine can be supplied only in narrow circumstances, as a "special" ordered by a prescriber to meet the special needs of an individual patient under their care, and one of the legal conditions is that no advertisement relating to the product is published by anyone. Report suspected side effects from an injection or drip through the MHRA Yellow Card scheme.

If you are buying an NR supplement

• Check the ingredient name. The authorised UK designation is "nicotinamide riboside chloride".
• Check the daily dose. The authorised maximum for adults is 300 mg a day, and 230 mg a day in pregnancy and breastfeeding.
• Look for a single ingredient. Blends with resveratrol, ginseng or extra B vitamins add cost and their own evidence questions, and make the NR dose harder to check.
• Expect a biomarker, not a feeling. NR raises blood NAD+, but trials have not shown a reliable change in energy or ageing.

What to ask a clinic before an injection or drip

• What exactly is in the bag or syringe, who made it, and is it a licensed medicine?
• What human evidence supports the benefit being promised, and was it a randomised trial?
• How fast will it run, and what happens if I get nausea, cramps or chest tightness?
• Who is the prescriber, and have they reviewed my medicines and medical history?
• Would an oral precursor raise my blood NAD+ for a fraction of the cost?

You can find practitioners in our professionals directory, and check a doctor on the GMC register, a nurse on the NMC register or a pharmacist on the GPhC register before booking.

FAQ

What is the best NAD+ supplement?

In the only direct comparison, NR and NMN raised blood NAD+ by about the same amount at 1,000 mg a day. In the UK, nicotinamide riboside chloride is the authorised option, at up to 300 mg a day.

Do NAD+ injections work?

They have not been shown to. No outcome trial has found that NAD+ injections or drips improve energy, wellbeing or ageing.

Is an NAD+ drip better than a supplement?

There is no evidence that it is. Oral precursors reliably raise blood NAD+, while drips lack outcome trials and, in the clinic records study, caused nausea, cramping and chest pressure in everyone who had them.

Does liposomal NAD+ work?

There is no published human trial showing that liposomal NAD+ raises blood NAD+ better than NR or NMN.

Is NMN legal in the UK?

NMN is not an authorised novel food in Great Britain. An application is in progress at the FSA.

Is NAD+ a peptide?

No. NAD+ is a dinucleotide, not a chain of amino acids.