Wegovy (semaglutide 2.4 mg) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for weight management in adults with obesity or those who are overweight with weight-related comorbidities. As with any prescription medicine, patients and clinicians may have concerns about potential adverse effects. One question that occasionally arises is whether Wegovy can cause seizures. This article examines the current evidence regarding Wegovy and seizure risk, reviews recognised neurological side effects, and provides guidance on when to seek medical attention whilst taking this medication.

Understanding Wegovy and Its Mechanism of Action

Wegovy (semaglutide 2.4 mg) is a prescription medicine licensed in the UK for weight management in adults with obesity or those who are overweight with at least one weight-related comorbidity. It is used as an adjunct to a reduced-calorie diet and increased physical activity. Wegovy belongs to a class of medications called glucagon-like peptide-1 (GLP-1) receptor agonists, which were originally developed for type 2 diabetes management but have demonstrated significant efficacy in promoting weight loss.

The mechanism of action centres on mimicking the naturally occurring hormone GLP-1, which is released from the intestine in response to food intake. Semaglutide binds to GLP-1 receptors in multiple tissues throughout the body, including the pancreas, gastrointestinal tract, and specific regions of the brain involved in appetite regulation. In the pancreas, it enhances glucose-dependent insulin secretion and suppresses inappropriate glucagon release, thereby improving glycaemic control. Within the gastrointestinal system, it slows gastric emptying, which prolongs the sensation of fullness after meals.

Crucially, semaglutide acts on GLP-1 receptors in the hypothalamus and other brain regions that regulate appetite and food intake. By reducing hunger signals and increasing satiety, patients typically experience a substantial reduction in caloric intake. This multi-targeted approach explains why Wegovy produces more significant weight loss compared to lifestyle interventions alone—clinical trials have demonstrated average weight reductions of approximately 10-15% of initial body weight over 68 weeks in the STEP clinical trial programme.

Wegovy is administered as a once-weekly subcutaneous injection, with doses gradually increased over 16-20 weeks to minimise gastrointestinal side effects. NICE guidance recommends its use within specialist weight management services for eligible patients who meet specific BMI criteria (generally ≥35 kg/m² with weight-related comorbidity, or ≥30 kg/m² with type 2 diabetes) for a maximum treatment duration of two years.

Can Wegovy Cause Seizures? Examining the Evidence

There is no established causal link between Wegovy and seizures based on current clinical evidence and regulatory data. Seizures are not listed among the known or common adverse effects in the Summary of Product Characteristics (SmPC) approved by the MHRA, nor do they appear in the comprehensive safety data from the STEP (Semaglutide Treatment Effect in People with obesity) clinical trial programme, which enrolled over 4,500 participants.

The European Medicines Agency (EMA) and MHRA conduct ongoing pharmacovigilance monitoring of all licensed medicines, including post-marketing surveillance to identify rare adverse events that may not emerge during clinical trials. To date, regulatory authorities have not issued safety alerts linking semaglutide to an increased risk of seizures. When isolated case reports of neurological events occur in patients taking any medication, regulatory bodies assess whether the temporal association represents causation or coincidence, particularly given that seizures can arise from numerous underlying causes unrelated to medication use.

It is important to recognise that patients seeking weight management treatment may have comorbidities or risk factors that independently predispose them to seizures, including uncontrolled diabetes with severe hypoglycaemia, electrolyte disturbances, or pre-existing neurological conditions. When Wegovy is used alongside insulin or sulphonylureas, dose adjustments of these medications may be necessary to reduce the risk of hypoglycaemia, which in severe cases can precipitate seizures.

Healthcare professionals should maintain a balanced perspective: whilst vigilance for any unexpected neurological symptoms is appropriate, there is currently insufficient evidence to suggest that Wegovy directly causes seizures. Patients concerned about this potential risk should discuss their individual medical history and any pre-existing neurological conditions with their prescribing clinician before commencing treatment.

Recognised Neurological Side Effects of Wegovy

Whilst seizures are not recognised adverse effects, Wegovy does have documented neurological side effects that patients and clinicians should be aware of. The most commonly reported neurological symptom is headache, which is classified as a 'common' side effect in the SmPC (affecting between 1 in 10 and 1 in 100 people). These headaches are typically mild to moderate in severity and often resolve as the body adjusts to the medication, particularly during the dose-escalation phase.

Dizziness represents another recognised neurological effect, also listed as 'common' in the SmPC. Patients experiencing dizziness should be advised to rise slowly from sitting or lying positions and to ensure adequate hydration, as dehydration can exacerbate this symptom.

Some patients report experiencing fatigue or tiredness, which, whilst not strictly a neurological side effect, can impact cognitive function and daily activities. This may be multifactorial, relating to caloric restriction, changes in eating patterns, or direct medication effects. It is generally advisable to monitor energy levels and ensure nutritional adequacy whilst taking Wegovy, particularly during the initial months of treatment.

Rare but serious neurological considerations include the risk of hypoglycaemia-related neurological symptoms in patients taking Wegovy alongside insulin or insulin secretagogues (such as sulphonylureas). Severe hypoglycaemia can manifest with confusion, altered consciousness, or in extreme cases, seizures. However, this risk is substantially lower with Wegovy monotherapy due to its glucose-dependent mechanism of action. The SmPC advises that the dose of insulin or insulin secretagogues may need to be reduced to minimise hypoglycaemia risk.

Patients should be counselled that most neurological side effects are transient and manageable. The prescribing clinician should conduct a thorough baseline assessment of neurological history and maintain appropriate monitoring throughout treatment, adjusting the dose escalation schedule if tolerability issues arise.

Risk Factors and Precautions for Neurological Events

Certain patient populations may require additional precautions and monitoring when considering Wegovy treatment, particularly those with factors that could theoretically influence neurological safety. Patients with a history of seizure disorders should have their condition well-controlled and stable before initiating weight management therapy. While there is no evidence that Wegovy directly affects seizure threshold, careful monitoring is advisable when initiating any new treatment in this population.

Individuals with poorly controlled diabetes face increased risk of hypoglycaemic episodes, which can present with neurological symptoms ranging from tremor and confusion to loss of consciousness. When Wegovy is prescribed alongside other glucose-lowering medications, dose adjustments of existing therapies may be necessary. NICE guidance (NG28) recommends considering a reduction in insulin or sulphonylurea doses when initiating GLP-1 receptor agonists to minimise hypoglycaemia risk. Patients should be educated on recognising hypoglycaemia symptoms and maintaining appropriate blood glucose monitoring.

Electrolyte disturbances represent another consideration, particularly in patients experiencing significant gastrointestinal side effects such as severe nausea, vomiting, or diarrhoea. Dehydration and electrolyte imbalances (particularly hyponatraemia or hypokalaemia) can affect neurological function. Patients should be advised to maintain adequate fluid intake and report persistent gastrointestinal symptoms promptly.

Those with cardiovascular disease should be monitored appropriately, as cardiovascular events can occasionally present with neurological manifestations. Individual risk assessment remains important when initiating any weight management therapy.

Medication interactions should be reviewed carefully. The SmPC notes that semaglutide delays gastric emptying, which could potentially influence the absorption of some oral medications. For medicines with a narrow therapeutic index (such as warfarin), increased monitoring (e.g., INR) may be appropriate when initiating or discontinuing semaglutide. Patients should inform all healthcare providers about their Wegovy treatment to ensure coordinated care and appropriate precautions.

When to Seek Medical Attention While Taking Wegovy

Patients taking Wegovy should be clearly informed about symptoms requiring prompt medical evaluation. Whilst serious neurological events are not established side effects, any unexpected neurological symptoms warrant clinical assessment to determine their cause and ensure patient safety.

Seek immediate medical attention (call 999 or attend A&E) if experiencing:

• Seizures or convulsions of any type, particularly if this is a new occurrence

• Loss of consciousness or fainting episodes

• Severe, sudden-onset headache unlike previous headaches, especially if accompanied by visual changes, neck stiffness, or confusion

• Symptoms suggestive of stroke, including sudden weakness, speech difficulties, facial drooping, or visual disturbances

• Severe hypoglycaemia symptoms with confusion, inability to concentrate, or altered consciousness (particularly relevant for patients on insulin or sulphonylureas)

• Severe, persistent abdominal pain (especially if radiating to the back) – stop taking Wegovy and seek urgent medical attention as this could indicate pancreatitis

Contact your GP or prescribing clinician within 24 hours for:

• Persistent or worsening headaches that do not respond to simple analgesia

• Recurrent dizziness affecting daily activities or balance

• Visual disturbances including blurred vision or changes in vision (noting that diabetic retinopathy complications have been reported with rapid glycaemic improvement)

• Unexplained confusion or cognitive changes

• Severe, persistent gastrointestinal symptoms (vomiting, diarrhoea) that may lead to dehydration

If you need urgent advice and it's not life-threatening, contact NHS 111.

Patients should maintain regular follow-up appointments as scheduled by their weight management service, typically every 3-6 months initially. These reviews allow monitoring of weight loss progress, assessment of side effects, and evaluation of any emerging concerns. The prescribing clinician should be informed of any new symptoms, even if they seem unrelated to Wegovy, to ensure comprehensive safety monitoring.

It is important to emphasise that most patients tolerate Wegovy well, with gastrointestinal effects being the most common side effects rather than neurological symptoms. If you suspect you are experiencing a side effect from Wegovy, you can report this through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk or via the Yellow Card app). Maintaining open communication with healthcare providers and understanding when to seek help ensures that any unexpected events are promptly evaluated and managed appropriately, supporting both safety and treatment success.

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