How long do NAD side effects last? Most side effects from NAD+ therapy are transient, with acute symptoms during intravenous infusions typically improving within hours of completion. Nicotinamide adenine dinucleotide (NAD+) is a coenzyme essential for cellular energy production, and supplementation has gained popularity in wellness settings. However, NAD+ therapy can produce side effects ranging from nausea and headaches to chest discomfort, particularly with IV administration. Understanding the expected duration of these effects is crucial for informed decision-making. In the UK, IV NAD+ products lack MHRA marketing authorisation and are not routinely offered by the NHS, making awareness of potential adverse reactions particularly important for those considering private treatment.

What Is NAD+ and Why Do People Use It?

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. NAD+ is also involved in DNA repair, gene expression, and cellular signalling pathways. As we age, cellular NAD+ levels naturally decline, which has led to interest in NAD+ supplementation and therapy.

NAD+ therapy typically involves intravenous (IV) infusions, intramuscular injections, or oral supplementation with NAD+ precursors such as nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). Some proponents suggest these interventions may support cellular health, enhance energy levels, improve cognitive function, and potentially slow aspects of biological ageing, though robust clinical evidence for these claims is currently limited. Some practitioners also advocate NAD+ therapy for addiction recovery, chronic fatigue, and neurodegenerative conditions, though scientific support for these applications remains insufficient.

In the UK, IV NAD+ products do not have a marketing authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA). When administered as IV infusions, NAD+ would generally be considered a medicine regulated by the MHRA and should only be used under appropriate prescribing and clinical governance as an unlicensed 'special'. For oral supplements, nicotinamide riboside (NR) is an authorised novel food with specified maximum daily intake limits, while nicotinamide mononucleotide (NMN) is not currently authorised as a novel food in Great Britain.

The NHS does not routinely offer NAD+ therapy, and NICE has not issued guidance on its use. NAD+ therapy is primarily available through private clinics. Due to limited safety data, NAD+ therapy is not recommended during pregnancy, breastfeeding, or for those under 18 years of age. Understanding potential side effects and their duration is essential for informed decision-making, particularly given the increasing popularity of these interventions in the wellness sector.

Common Side Effects of NAD+ Therapy

The side effects associated with NAD+ therapy vary considerably depending on the route of administration, with intravenous infusions typically producing more immediate and noticeable reactions than oral supplementation. During IV NAD+ infusions, patients commonly report a constellation of symptoms that may include:

• Gastrointestinal disturbances: Nausea, abdominal cramping, and occasionally vomiting are frequently reported, particularly when infusion rates are too rapid

• Chest discomfort: Some patients report a sensation of heaviness or pressure in the chest area, which typically improves when the infusion is slowed

• Headache: Ranging from mild to moderate intensity

• Muscle cramping: Particularly in the legs and abdomen

• Anxiety or restlessness: Some individuals report feeling jittery during infusion

• Infusion site reactions: Pain, redness, or swelling at the injection site

• Potential infection risk: As with any IV therapy, there is a risk of infection or thrombophlebitis

The mechanism underlying these side effects is not fully understood but may relate to changes in cellular metabolic activity. When NAD+ is administered intravenously, it bypasses normal digestive and hepatic metabolism, leading to a sudden increase in circulating levels.

Oral NAD+ precursors (NR or nicotinamide) generally produce milder side effects, most commonly mild gastrointestinal upset, including nausea, diarrhoea, or indigestion. Unlike nicotinic acid (niacin), which commonly causes flushing, nicotinamide, NR and NMN rarely cause this effect. Headaches and fatigue have also been reported, particularly when initiating supplementation or with higher doses. The slower absorption and hepatic first-pass metabolism of oral preparations likely account for the reduced intensity of adverse effects compared to IV administration.

IV NAD+ therapy should only be administered by qualified healthcare professionals with appropriate training in IV therapy, with resuscitation equipment available and protocols in place to manage potential adverse reactions.

How Long Do NAD+ Side Effects Typically Last?

The duration of NAD+ side effects appears to be linked to the route of administration and the specific symptoms experienced, though it's important to note that formal studies documenting precise durations are limited. For intravenous NAD+ therapy, most acute side effects occur during the infusion itself or shortly after treatment. Many symptoms—including nausea, chest discomfort, muscle cramping—often improve when the infusion rate is slowed or stopped. This suggests these effects are related to the rate of administration rather than cumulative toxicity.

Based on clinical experience, though not well-documented in published research, many practitioners report that most acute symptoms typically improve within hours after the infusion is completed. Some individuals may experience lingering effects such as mild headaches or fatigue that can persist for several hours post-infusion. These extended symptoms are generally mild and self-limiting, often resolving without intervention by the following day. Symptoms continuing beyond 24 hours are less common and warrant medical review to exclude other causes.

Oral NAD+ precursors tend to produce side effects with a different pattern. Gastrointestinal symptoms such as nausea or loose stools may occur within hours of ingestion and typically resolve within the same day. When side effects do occur with oral supplementation, they often diminish over time as the body adapts to the supplement. Some individuals find that taking oral NAD+ precursors with food significantly reduces gastrointestinal side effects.

Long-term safety data for NAD+ supplementation remain limited, particularly for higher doses and extended use. For nicotinamide riboside, the European Food Safety Authority has established safety parameters and maximum intake levels for its use as a novel food. Most reported adverse effects appear to be transient and related to the acute administration of NAD+ rather than indicating serious pathology. However, if side effects persist or are severe, it's important to discontinue use and seek medical advice.

Factors That Affect NAD+ Side Effect Duration

Several variables may influence both the severity and duration of NAD+ side effects. Infusion rate is a significant factor for IV therapy. Rapid infusions are often associated with more intense symptoms, whilst slower infusions generally produce milder reactions. Many practitioners adjust the rate based on individual tolerance.

Dosage may correlate with side effect profile. Higher doses of NAD+ (whether IV or oral) might be more likely to produce noticeable side effects. For oral precursors, it's important to note that nicotinamide riboside (NR) has an authorised maximum daily intake in the UK as a novel food, and exceeding these levels is not recommended. Nicotinamide mononucleotide (NMN) is not currently authorised as a novel food in Great Britain.

Individual factors may play a role in determining side effect duration, including:

• Hepatic metabolism: Variations in liver function may affect how quickly NAD+ and its metabolites are processed

• Pre-existing gastrointestinal conditions: Such as irritable bowel syndrome or gastritis, may influence digestive symptoms

• Cardiovascular sensitivity: May affect how individuals experience symptoms like chest discomfort

Hydration status may influence how individuals tolerate IV therapy in general. Concurrent medications could potentially influence side effect profiles, which is why it's important to review all medicines with a GP or pharmacist before starting NAD+ therapy. Some practitioners suggest that patients receiving regular NAD+ therapy may experience fewer side effects with subsequent treatments, though this observation is anecdotal and not well-documented in clinical studies.

Pregnant or breastfeeding women and individuals under 18 years of age should avoid NAD+ therapy due to insufficient safety data. Anyone with pre-existing medical conditions should consult their GP before considering NAD+ supplementation to ensure it's appropriate for their individual circumstances.

When to Seek Medical Advice About NAD+ Side Effects

Whilst most NAD+ side effects are transient and benign, certain symptoms warrant prompt medical evaluation. You should call 999 or go to A&E immediately if you experience:

• Severe or persistent chest pain: Particularly if accompanied by shortness of breath, radiating pain to the arm or jaw, or sweating, as these may indicate a heart attack

• Significant breathing difficulties: Wheezing, stridor, or sensation of throat closure, which could suggest an allergic reaction or anaphylaxis

• Severe allergic reactions: Widespread hives, facial or tongue swelling, or signs of anaphylaxis require immediate emergency care

Contact your GP or call NHS 111 if you experience:

• Persistent vomiting: Lasting more than 6 hours or preventing oral fluid intake, risking dehydration

• Neurological symptoms: Such as visual disturbances, severe headache unlike previous headaches, confusion, seizures, or focal neurological deficits

• Symptoms persisting beyond 24 hours: Any side effect that continues past the expected resolution timeframe

• Infusion site problems: Increasing pain, redness, swelling, warmth, or streaking from the injection site, especially if accompanied by fever

Routine GP consultation is advisable if you experience recurrent side effects with each dose that significantly impact quality of life, or if you have concerns about the appropriateness of NAD+ therapy given your medical history. Individuals with pre-existing cardiovascular disease, hepatic impairment, renal dysfunction, or those taking multiple medications should consult their GP before initiating NAD+ therapy.

When receiving IV NAD+ therapy, ensure your provider is registered with the Care Quality Commission (CQC), has appropriate medical qualifications, emergency protocols, and clear pathways for managing adverse reactions. Any NAD+ therapy should be discussed with your regular GP, particularly if you have complex medical conditions or take prescription medications.

If you experience any suspected side effects from NAD+ therapy, you can report them to the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk), which monitors the safety of medicines, medical devices, and cosmetic products in the UK.

Frequently Asked Questions