NAD injections have gained popularity in private wellness clinics, with proponents claiming benefits for energy, cognitive function, and anti-ageing. However, these treatments are not licensed by the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK and can only be supplied as 'specials' on individual prescription. Understanding the potential side effects—from mild injection site reactions to serious allergic responses—is essential for anyone considering this therapy. This article examines the common and serious adverse effects of NAD injections, identifies who should avoid treatment, and clarifies the UK regulatory position to help patients make informed decisions about this unlicensed intervention.

What Are NAD Injections and How Do They Work?

Nicotinamide adenine dinucleotide (NAD) is a coenzyme found naturally in every cell of the human body, playing a crucial role in energy metabolism and cellular repair processes. NAD injections deliver this molecule directly into the bloodstream, either through intravenous (IV) infusion or intramuscular injection, bypassing the digestive system. While this is theoretically expected to achieve higher bioavailability than oral supplements, robust human pharmacokinetic data comparing these routes remains limited.

Proponents of NAD therapy suggest it may support cellular energy production, DNA repair, and mitochondrial function. The treatment has gained attention in wellness circles for purported benefits including improved energy levels, cognitive function, and anti-ageing effects. Some practitioners also promote NAD injections for addiction recovery or chronic fatigue, though it's important to note that NAD therapy is not recommended by the National Institute for Health and Care Excellence (NICE) for these conditions, and robust clinical evidence for many claimed applications remains limited.

The mechanism of action centres on NAD's role as an essential cofactor in redox reactions throughout the body. NAD exists in two forms: NAD+ (oxidised) and NADH (reduced), which shuttle electrons in metabolic pathways including glycolysis and the citric acid cycle. As we age, cellular NAD+ levels naturally decline, which has led to interest in supplementation strategies.

Patients considering NAD injections should understand that whilst the molecule itself is naturally occurring, injectable NAD preparations are not licensed as medicines by the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK. Under UK regulations, these preparations should only be supplied as 'specials' on prescription to meet the special needs of an individual patient, with the prescriber assuming responsibility. Unlicensed medicines cannot be advertised to the public and cannot be supplied under Patient Group Directions (PGDs). Treatments are typically offered through private clinics rather than NHS pathways, and patients should approach claims with appropriate scepticism.

Common Side Effects of NAD Injections

NAD injections can produce a range of side effects, many of which are related to the rate and route of administration. Most side effect reports come from uncontrolled observations rather than systematic clinical trials, and the frequency and severity can vary considerably between individuals.

Injection site reactions are common with intramuscular NAD administration and may include:

• Pain, tenderness, or discomfort at the injection site

• Localised redness or swelling

• Bruising or minor bleeding

• Temporary muscle soreness

Systemic effects during IV infusion commonly reported include:

• Nausea and abdominal cramping, which appear to be dose-dependent and related to infusion speed

• Flushing or warmth spreading through the body

• Chest tightness or pressure (which should prompt immediate slowing or stopping of the infusion)

• Headache or light-headedness

• Fatigue immediately following treatment

Many practitioners report that slowing the infusion rate significantly reduces the intensity of these symptoms. Some patients describe an uncomfortable sensation during rapid IV administration, which has led clinics to extend infusion times from 30 minutes to several hours to improve tolerability.

General IV therapy risks also apply to NAD infusions, including:

• Phlebitis (inflammation of the vein)

• Extravasation (leakage of fluid into surrounding tissue)

• Local infection at the insertion site

• Potential for line-related complications

It is essential that NAD infusions are administered by appropriately registered healthcare professionals with facilities to monitor vital signs, manage adverse reactions, and adjust or stop the infusion if needed. Proper aseptic technique and infection control measures are crucial for safety.

Patients experiencing any concerning symptoms during treatment should immediately alert the healthcare provider administering the infusion. Suspected adverse reactions should be reported to the MHRA through the Yellow Card Scheme, even if receiving treatment in a private setting.

Serious Risks and When to Seek Medical Help

Whilst most side effects of NAD injections are mild and self-limiting, there are potential serious risks that warrant immediate medical attention. Understanding these warning signs is essential for patient safety.

Allergic and hypersensitivity reactions, though uncommon, represent the most concerning acute risk. Call 999 or go to A&E immediately if you experience:

• Difficulty breathing or shortness of breath

• Swelling of the face, lips, tongue, or throat

• Widespread rash, hives, or severe itching

• Rapid heartbeat or palpitations accompanied by dizziness

• Severe chest pain or tightness

Cardiovascular concerns require prompt evaluation. Contact your GP or call NHS 111 if you develop persistent irregular heartbeat, sustained chest discomfort, or significant changes in blood pressure following NAD injection. Individuals with pre-existing cardiac conditions may be at higher risk for cardiovascular effects, though the precise risk profile remains poorly characterised in clinical literature.

Neurological symptoms that persist beyond the immediate treatment period should be assessed by a healthcare professional. These include severe or worsening headaches, visual disturbances, persistent dizziness, confusion, or seizure activity.

Signs of infection at injection sites—including increasing pain, warmth, redness spreading beyond the immediate area, pus or discharge, or fever—require medical review to exclude cellulitis or abscess formation. If you develop fever with rigors (shaking chills) or notice redness tracking along a vein after IV treatment, seek urgent medical attention as this could indicate a serious infection.

IV line complications can occur after treatment. Seek medical advice if you notice rapidly spreading redness, streaking from the injection site, or develop fever within days of treatment.

Patients should also seek medical advice if they experience severe or persistent nausea and vomiting that prevents adequate fluid intake, as this may lead to dehydration. When seeking help, inform clinicians about the NAD injection, including dose, route, and timing, as many healthcare professionals may have limited familiarity with this treatment.

Who Should Avoid NAD Injections?

Certain individuals should exercise caution or avoid NAD injections altogether due to potential health risks or lack of safety data in specific populations. As NAD therapy is not licensed as a medicine in the UK, comprehensive safety profiles for vulnerable groups are not established through the rigorous processes required for MHRA approval.

Pregnant and breastfeeding women should avoid NAD injections. There is insufficient evidence regarding the safety of supraphysiological NAD administration during pregnancy or lactation, and the potential effects on foetal development or nursing infants are unknown.

Individuals with cardiovascular disease should approach NAD injections with considerable caution. Those with a history of heart attack, arrhythmias, uncontrolled hypertension, or other significant cardiac conditions may face increased risks, as NAD infusions can affect heart rate and blood pressure. A thorough cardiovascular assessment and specialist consultation would be prudent before considering treatment.

People with active cancer or a recent cancer history should discuss NAD therapy with their oncologist. There is theoretical concern that boosting cellular metabolism could potentially affect cancer cell behaviour, though this remains speculative and requires further research.

Those with bleeding disorders or taking anticoagulant medications should be cautious, particularly with intramuscular injections, which carry increased bleeding and haematoma risk.

Additional groups who should seek specialist advice before NAD injections include:

• Individuals with kidney or liver disease (due to insufficient data on clearance)

• People with a history of hypersensitivity to medicinal products or their excipients

• Children and adolescents (no paediatric safety data available)

Patients taking multiple medications should consult a healthcare professional regarding potential drug interactions, as comprehensive interaction data for injectable NAD is limited.

It is important to understand that any use of NAD injections should be on an individual prescription by an appropriate prescriber. As an unlicensed medicine, NAD injections cannot be supplied under Patient Group Directions (PGDs), which has implications for how and where these treatments can be legally provided.

Safety Considerations and UK Regulatory Status

The regulatory status of NAD injections in the UK is an important consideration for anyone contemplating this treatment. NAD injections are not currently licensed by the MHRA as medicines for any specific medical indication, which means they have not undergone the rigorous safety and efficacy testing required for approved pharmaceuticals.

Under UK regulations, injectable NAD preparations should only be supplied as 'specials' on prescription to meet the special needs of an individual patient, with the prescriber assuming responsibility for the decision to use an unlicensed product. It is important to note that unlicensed medicines cannot be advertised to the public and cannot be supplied under Patient Group Directions (PGDs).

In practice, NAD injections are typically offered through private wellness clinics, aesthetic medicine practices, or complementary health providers. This variability in sourcing and preparation raises important quality and safety concerns, including potential differences in purity, sterility, concentration, and formulation between providers.

Patients considering NAD injections should carefully evaluate the credentials and clinical governance of any provider. Key safety considerations include:

• Ensuring the practitioner is appropriately qualified and registered with relevant professional bodies

• Confirming the clinic is registered with the Care Quality Commission (CQC) where required

• Verifying that proper sterile technique and infection control measures are followed

• Confirming that emergency equipment and medications are available to manage adverse reactions

• Requesting information about the source, quality assurance, and batch testing of NAD preparations

• Understanding that treatment is not covered by NHS services and falls outside standard clinical pathways

Evidence limitations are significant. Whilst preliminary research suggests NAD may have biological effects, large-scale randomised controlled trials demonstrating clinical benefit for specific conditions are lacking. NICE has not issued guidance on NAD therapy and does not recommend it for conditions such as addiction or ME/CFS, for which evidence-based NHS pathways exist.

From a patient safety perspective, individuals should inform their GP about any NAD treatments received, particularly before surgery or when starting new medications. Maintaining open communication with NHS healthcare providers ensures comprehensive medical records and allows for appropriate monitoring of potential interactions or complications. Anyone experiencing adverse effects should report these to the MHRA's Yellow Card Scheme, contributing to the broader understanding of NAD injection safety in real-world use.

Frequently Asked Questions