Wegovy (semaglutide 2.4 mg) is a once-weekly injection licensed for weight management in adults with obesity or overweight with comorbidities. Whilst effective for weight loss, questions have emerged about whether Wegovy can cause mental health issues. Current evidence from regulatory reviews by the European Medicines Agency and FDA does not establish a definitive causal link between semaglutide and mental health disorders, though ongoing monitoring continues. This article examines the available evidence, reported symptoms, risk factors, and guidance for patients and healthcare professionals navigating mental health concerns during Wegovy treatment.
Quick Answer: Current evidence from European and US regulatory reviews does not establish a causal link between Wegovy (semaglutide) and mental health disorders, though monitoring continues.
Wegovy (semaglutide 2.4 mg) is a once-weekly subcutaneous injection licensed in Great Britain for weight management in adults with obesity (BMI ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) with at least one weight-related comorbidity, such as type 2 diabetes, hypertension, or obstructive sleep apnoea, as an adjunct to diet and physical activity.
Within the NHS, Wegovy is recommended by NICE (TA875) for use only within specialist weight management services. NHS eligibility criteria include specific BMI thresholds and treatment is typically limited to a maximum duration of 2 years.
Semaglutide belongs to a class of medications called glucagon-like peptide-1 (GLP-1) receptor agonists. These drugs work by mimicking the action of the naturally occurring hormone GLP-1, which is released from the gut after eating. The mechanism of action involves several pathways: it slows gastric emptying, which prolongs the feeling of fullness after meals; it acts on appetite centres in the brain to reduce hunger signals; and it enhances insulin secretion while suppressing glucagon release when blood glucose levels are elevated.
In the STEP clinical trials, Wegovy demonstrated significant weight loss outcomes, with participants losing an average of 12–15% of their initial body weight over 68 weeks when combined with lifestyle interventions. This substantial weight reduction can lead to improvements in cardiovascular risk factors, glycaemic control in those with diabetes, and overall quality of life. However, as with all medications, Wegovy carries potential side effects that require careful monitoring, including questions about its impact on mental health and psychological wellbeing.
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Start HereThe relationship between Wegovy and mental health remains an area of ongoing scrutiny and research. There is currently no definitively established causal link between semaglutide and the development of mental health disorders. In April 2024, the European Medicines Agency's Pharmacovigilance Risk Assessment Committee (PRAC) concluded that available evidence does not support a causal association between GLP-1 receptor agonists (including Wegovy) and suicidal thoughts or behaviours, following a comprehensive review of clinical trial data and post-marketing surveillance reports. Nevertheless, the PRAC recommended continued monitoring and advised healthcare professionals to remain vigilant.
The US Food and Drug Administration (FDA) has similarly been investigating reports of suicidal thoughts in patients taking GLP-1 receptor agonists for weight management and diabetes, though no definitive causal relationship has been established.
It is important to recognise that obesity itself is associated with higher rates of depression, anxiety, and other mental health conditions. The complex interplay between body weight, self-esteem, societal stigma, and psychological wellbeing means that individuals seeking weight management treatment may already have pre-existing mental health vulnerabilities. Additionally, the process of significant weight loss—regardless of the method—can trigger psychological changes, including mood fluctuations, altered body image perceptions, and changes in social relationships. Therefore, distinguishing between medication effects, pre-existing conditions, and the psychological impact of weight loss itself presents considerable challenges in determining causality.
Post-marketing surveillance and patient reports have documented various mental health-related symptoms in individuals taking Wegovy, though the frequency and severity vary considerably. The most commonly reported psychological symptoms include:
Mood changes and irritability – Some patients describe feeling more emotionally labile, experiencing mood swings, or becoming more easily frustrated during treatment
Anxiety symptoms – Reports of increased worry, restlessness, or generalised anxiety have been documented, though these may also relate to lifestyle changes or pre-existing tendencies
Depressive symptoms – A subset of patients report low mood, loss of interest in activities, or feelings of sadness
Suicidal ideation – Rare reports of suicidal thoughts have been investigated by regulatory authorities, though no causal relationship has been established
In the pivotal STEP clinical trial programme for Wegovy, psychiatric adverse events were generally low and similar between the semaglutide and placebo groups. It is worth noting that the current UK Summary of Product Characteristics (SmPC) for Wegovy does not list suicidality as an adverse reaction, although regulatory authorities continue to monitor this area closely.
It is crucial to note that gastrointestinal side effects are very common with Wegovy. According to the UK SmPC, nausea affects more than 1 in 10 users, as do diarrhoea and vomiting. These physical symptoms can indirectly impact mental wellbeing, causing distress, affecting sleep quality, and reducing overall quality of life. The distinction between direct neuropsychiatric effects and the psychological burden of managing uncomfortable physical side effects is not always clear in clinical practice.
Certain individuals may be at higher risk of experiencing mental health changes whilst taking Wegovy, though research in this area remains limited. Pre-existing mental health conditions represent the most significant risk factor. Patients with a history of depression, anxiety disorders, bipolar disorder, or previous suicidal ideation should be monitored particularly carefully when initiating weight management medications. The current UK prescribing information for Wegovy does not list psychiatric disorders as absolute contraindications, but clinical judgement and individualised risk assessment are essential.
Additional vulnerability factors may include:
Concurrent stressful life circumstances – Major life changes, relationship difficulties, or occupational stress may compound any mood effects
Inadequate support systems – Lack of family, social, or professional psychological support during weight loss treatment
Rapid or substantial weight loss – Dramatic body composition changes can affect psychological adjustment and body image
Polypharmacy – Taking multiple medications that may interact or have cumulative effects on mood and cognition
Substance use history – Previous or current alcohol or drug use may complicate mental health monitoring
Younger adults and adolescents may represent a particularly vulnerable group, though Wegovy is not currently licensed for use in individuals under 18 years in the UK. The developing brain and the psychological challenges of adolescence may create additional risks that require careful consideration.
As recommended clinical best practice within specialist weight management services, healthcare professionals should conduct thorough baseline mental health assessments before prescribing Wegovy, including screening for depression, anxiety, suicidal ideation, and eating disorders. This establishes a reference point for monitoring changes during treatment and allows for informed shared decision-making about whether the benefits of treatment outweigh potential risks for each individual patient.
If you notice any changes in your mood, thoughts, or behaviour whilst taking Wegovy, prompt communication with your healthcare provider is essential. Your prescriber needs to assess your symptoms and determine the most appropriate course of action.
Contact your GP or prescribing clinician if you experience:
Persistent low mood lasting more than two weeks
Loss of interest or pleasure in activities you normally enjoy
Significant changes in sleep patterns (insomnia or excessive sleeping)
Unusual anxiety, panic attacks, or overwhelming worry
Difficulty concentrating or making decisions
Changes in appetite beyond the expected effects of the medication
Withdrawal from social activities or relationships
Seek urgent medical attention or contact emergency services (999) if you experience:
Thoughts of self-harm or suicide
Plans or intentions to harm yourself
Feelings that life is not worth living
Severe depression or hopelessness
If experiencing suicidal thoughts or intent, seek urgent help (999 or A&E) and contact a clinician; stopping the medicine may be advised by the clinician. For urgent but non-life-threatening concerns outside of normal hours, NHS 111 can provide guidance.
Your healthcare provider may recommend several approaches, including dose adjustment (temporarily reducing or pausing Wegovy), additional monitoring with more frequent follow-up appointments, referral to mental health services for specialist assessment and support, or discontinuation of treatment if the risks outweigh the benefits in your individual circumstances.
It is also valuable to maintain a symptom diary documenting your mood, energy levels, and any concerning thoughts or feelings. This provides objective information to help your healthcare team distinguish between medication effects, the psychological impact of weight loss, and other contributing factors. Remember that mental health support services, including NHS Talking Therapies and crisis helplines such as Samaritans (116 123), are available if you need immediate support whilst awaiting medical review.
Patients and healthcare professionals are encouraged to report suspected side effects of Wegovy via the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk or the Yellow Card app).
Current evidence from the European Medicines Agency and FDA does not establish a causal link between Wegovy and depression or suicidal thoughts, though regulatory authorities continue monitoring reports. Patients with pre-existing mental health conditions should be monitored carefully during treatment.
Reported symptoms include mood changes, irritability, anxiety, and depressive symptoms, though these occur at low rates similar to placebo in clinical trials. Distinguishing medication effects from pre-existing conditions and the psychological impact of weight loss itself remains challenging.
Contact your GP for persistent low mood lasting over two weeks, unusual anxiety, or withdrawal from activities. Seek urgent help via 999 or A&E immediately if you experience suicidal thoughts, self-harm intentions, or severe depression.
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