Nicotinamide adenine dinucleotide (NAD+) injections have gained attention in private wellness clinics as a potential intervention for fatigue, cognitive function, and age-related decline. NAD+ is a coenzyme essential for cellular energy production and DNA repair, with levels naturally declining as we age. Administered via intramuscular or intravenous routes, these injections are marketed for various health benefits. However, it is crucial to understand that NAD injections are not licensed medicines in the UK and lack robust clinical evidence supporting their efficacy. This article examines the proposed benefits, safety considerations, and important regulatory context for anyone considering this unlicensed therapy.

What Are NAD Injections and How Do They Work?

Nicotinamide adenine dinucleotide (NAD+) is a coenzyme found in all living cells that plays a fundamental role in cellular metabolism and energy production. It exists in two forms: NAD+ (oxidised) and NADH (reduced), both essential for redox reactions that convert nutrients into cellular energy through mitochondrial function. NAD+ levels naturally decline with age, and this reduction has been associated with various age-related physiological changes.

NAD injections deliver this coenzyme via intramuscular (IM) or intravenous (IV) administration. IV administration delivers NAD+ directly into the bloodstream, while IM injections deliver it into muscle tissue with subsequent absorption into circulation. Proponents suggest that these routes may allow for higher bioavailability compared to oral supplementation, though it's important to note that human pharmacokinetics, tissue distribution and durability of NAD+ level changes after injection are not well characterised.

At the cellular level, NAD+ serves as a crucial cofactor for enzymes called sirtuins, which regulate DNA repair, inflammation, and cellular stress responses. It also supports the function of poly(ADP-ribose) polymerases (PARPs), enzymes involved in DNA damage repair. Additionally, NAD+ is essential for the electron transport chain in mitochondria, the cellular powerhouses responsible for adenosine triphosphate (ATP) production.

It is important to note that NAD injections are not licensed as medicines by the MHRA (Medicines and Healthcare products Regulatory Agency) in the UK. They are supplied as unlicensed medicines ('specials') and must be prescribed on a patient-specific basis by an appropriate prescriber with informed consent. There are no standardised doses or formulations, and quality may vary. NAD injections are primarily offered through private wellness clinics as complementary therapies. The evidence base for their clinical efficacy remains limited, with most research conducted in laboratory settings or animal models rather than robust human clinical trials.

Potential Benefits of NAD Injections for Health and Wellbeing

Advocates of NAD injection therapy claim a range of potential health benefits, though it is essential to emphasise that high-quality clinical evidence supporting these claims in humans is currently limited. The proposed benefits are largely extrapolated from preclinical research and theoretical mechanisms of action. There are no NICE-endorsed indications for NAD injections in the UK.

Energy and fatigue reduction represents one of the most commonly cited potential benefits. Given NAD+'s central role in mitochondrial ATP production, proponents suggest that supplementation may enhance cellular energy metabolism, potentially reducing feelings of fatigue. Some individuals report subjective improvements in energy levels and mental clarity, though placebo effects cannot be excluded without controlled trials.

Cognitive function and neuroprotection have also been areas of interest. Animal studies suggest NAD+ may support neuronal health and synaptic plasticity, leading to speculation about potential benefits for memory, focus, and age-related cognitive decline. However, there is no established link between NAD injections and prevention or treatment of neurodegenerative conditions in humans.

Metabolic health and weight management represent another proposed benefit area. NAD+ influences metabolic pathways including glucose and lipid metabolism. Some research suggests NAD+ precursors may improve insulin sensitivity in animal models, but translation to human metabolic disorders remains unproven. It's important to note that evidence from oral NAD+ precursors (NR/NMN) should not be extrapolated to IV/IM NAD+ administration.

Anti-ageing and cellular repair claims are frequently made, based on NAD+'s role in DNA repair and sirtuin activation. While cellular senescence and NAD+ decline are associated with ageing, there is insufficient evidence that NAD injections can reverse or significantly slow human ageing processes.

Addiction recovery support has been explored in some private clinics, with anecdotal reports of reduced cravings and withdrawal symptoms. However, NICE guidelines for substance misuse do not include NAD therapy, and evidence remains largely anecdotal. Anyone seeking addiction treatment should follow evidence-based pathways through NHS drug and alcohol services or contact FRANK (www.talktofrank.com) for confidential advice and referral to accredited programmes.

Safety Considerations and Side Effects of NAD Injections

The safety profile of NAD injections has not been comprehensively established through large-scale clinical trials, and regulatory oversight in the UK wellness sector varies. As these are unlicensed medicines, it is particularly important that any suspected adverse reactions are reported to the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Common side effects reported anecdotally include:

• Injection site reactions: pain, redness, swelling, or bruising at the IM injection site

• Flushing and warmth: particularly with IV administration, possibly due to vasodilation

• Nausea and gastrointestinal discomfort: some individuals report mild digestive upset

• Headache and dizziness: occasionally reported, particularly with rapid IV infusion

• Fatigue or restlessness: paradoxically, some people experience temporary tiredness or agitation

IV-specific risks include infection, thrombophlebitis, extravasation, and rarely, air embolism. Anaphylactic reactions, while uncommon, are possible with any injectable product. Clinics should have appropriate resuscitation equipment and trained staff available.

Infusion rate appears important for tolerability. Rapid IV administration may increase the likelihood of flushing, chest tightness, or anxiety-like sensations. Reputable clinics typically administer NAD+ slowly over several hours to minimise these effects.

Contraindications and cautions are not well-defined due to limited research, but individuals should exercise particular caution if they have:

• Active malignancy (theoretical concerns about supporting cancer cell metabolism)

• Cardiovascular conditions (effects on blood pressure and heart rate are not fully characterised)

• Pregnancy or breastfeeding (should be avoided due to absence of safety data)

• Children and adolescents under 18 (should be avoided outside clinical trials)

• Severe liver or kidney impairment (metabolism and excretion pathways unclear)

Quality and governance considerations are significant. NAD injections should be sourced from GMP-compliant manufacturers as unlicensed 'specials', with batch numbers and sterility certificates. Patients should verify that clinics are registered with appropriate regulatory bodies (CQC in England, HIS in Scotland, HIW in Wales, or RQIA in Northern Ireland) and that practitioners hold appropriate professional registration (GMC, NMC, HCPC or GPhC).

Anyone considering NAD injections should consult their GP first, particularly if they have existing medical conditions or take regular medications. Potential drug interactions have not been systematically studied. If adverse effects occur following NAD injection, individuals should contact their GP or NHS 111 for advice, and serious reactions warrant immediate medical attention.

Who Might Consider NAD Injection Therapy in the UK?

Given the limited evidence base and lack of NICE guidance or MHRA licensing, NAD injections should not be considered a first-line treatment for any medical condition. They are currently positioned as complementary wellness interventions rather than evidence-based medical therapies.

Individuals who might explore NAD injection therapy typically fall into several categories, though all should maintain realistic expectations:

Those experiencing persistent fatigue not explained by diagnosed medical conditions may consider NAD therapy after appropriate medical investigation. However, it is crucial that fatigue is properly evaluated first. Red flags requiring urgent medical assessment include unintentional weight loss, persistent fever or night sweats, chest pain, new breathlessness, rectal bleeding, or focal neurological symptoms.

NICE recommends thorough assessment for conditions such as anaemia, thyroid disorders, diabetes, depression, and chronic fatigue syndrome/ME. Initial tests typically include full blood count, kidney and liver function, thyroid function, HbA1c, ferritin, inflammatory markers, B12/folate, and coeliac serology. NAD injections should never replace proper diagnostic workup.

Individuals interested in longevity and preventive health sometimes pursue NAD therapy as part of broader wellness strategies. While optimising NAD+ levels theoretically supports healthy ageing, lifestyle interventions with proven benefits—including regular physical activity, Mediterranean-style diet, adequate sleep, and stress management—should form the foundation of any anti-ageing approach.

People seeking complementary support during recovery from illness or intense physical training occasionally use NAD injections, though evidence for enhanced recovery is lacking. Conventional rehabilitation, physiotherapy, and nutritional support remain the evidence-based standards.

Important considerations for anyone contemplating NAD injection therapy include:

• Cost: treatments are not NHS-funded and can be expensive (costs vary widely)

• Clinic selection: choose facilities registered with appropriate regulatory bodies (CQC/HIS/HIW/RQIA) and verify practitioner registration (GMC/NMC/HCPC/GPhC)

• Realistic expectations: approach claims critically and recognise the evidence limitations

• Complementary not alternative: never use NAD injections to replace proven medical treatments

• Monitoring: any therapy should be discontinued if no subjective benefit is experienced

Patients should be particularly cautious of clinics making exaggerated claims about curing diseases or guaranteeing specific outcomes. If you have a diagnosed medical condition, always discuss any complementary therapy with your NHS healthcare team to ensure it does not interfere with evidence-based treatment or delay necessary medical care.

Frequently Asked Questions