Updated 12 July 2026

Mysimba UK: prices, access and safety

Mysimba is a prescription weight-management tablet containing naltrexone and bupropion. It is not a GLP-1 medicine, is not the same as the Wegovy pill and should only be considered after a proper clinical assessment.

What is Mysimba?

Mysimba contains two prolonged-release active ingredients: naltrexone hydrochloride 8mg and bupropion hydrochloride 90mg. It is intended to be used alongside a reduced-calorie diet and increased physical activity, not as a replacement for them.

Naltrexone and bupropion affect appetite and reward pathways in different ways. The combination is not suitable for everyone, and the product information sets out important contraindications and monitoring requirements.

Who may be assessed for Mysimba?

UK prescribing decisions depend on the licensed product information and the clinician’s assessment. BMI, weight-related health conditions, blood pressure, mental-health history, seizure risk, current medicines and previous treatment all matter. Do not rely on a checklist alone to decide whether Mysimba is right for you.

NICE guidance should also be checked for the current NHS position. Private availability does not mean a medicine is routinely supplied through the NHS.

Starting and follow-up care

Mysimba is introduced and reviewed under a prescribing plan. The product information includes a staged schedule, but the right starting point, follow-up and any change in treatment depend on the clinician’s assessment and the directions supplied with the prescription. Do not copy a schedule from another person, restart after a break or change the amount taken without speaking to the prescriber or pharmacist.

Keep the patient information leaflet that arrives with the medicine. It is the right reference for the exact product supplied, and it explains when to contact the provider about side effects, missed tablets or changes to other medicines.

Who must not take Mysimba?

Mysimba has important contraindications. Tell the clinician about any current or past seizure disorder, eating disorder, uncontrolled high blood pressure, bipolar disorder, serious liver or kidney problems, heart problems, pregnancy or breastfeeding.

Naltrexone can interact with opioid medicines. This includes opioid painkillers and opioid-substitution treatment. Disclose every prescription medicine, over-the-counter product and supplement, including occasional medicines such as codeine-containing products. Never conceal opioid use to obtain a prescription.

Side effects and monitoring

Nausea, constipation, vomiting, headache, dizziness, dry mouth and sleep disturbance are among the effects described for Mysimba. Blood pressure and heart rate may need attention, particularly during early treatment. The separate Mysimba side-effects guide explains the safety questions in more detail.

Seek urgent medical help for a seizure, a serious allergic reaction, severe chest pain, severe confusion or another symptom that feels immediately dangerous. Contact the prescribing service promptly if symptoms are persistent or difficult to manage.

How to get Mysimba safely in the UK

1. Use a genuine UK prescribing service with a clinical assessment.
2. Provide a complete medical and medication history.
3. Check the prescriber and dispensing pharmacy details.
4. Confirm the medicine, pack size, total price and delivery terms.
5. Keep the provider’s follow-up route and patient information leaflet.

A website that offers Mysimba without an assessment or prescription should be treated as a serious warning sign. Price alone cannot establish that a medicine is genuine, suitable or safely supplied.

Mysimba compared with other tablets

Mysimba is not Orlistat and it is not a GLP-1 medicine. Orlistat reduces dietary fat absorption. The Wegovy pill is oral semaglutide for weight management. Rybelsus is oral semaglutide for type 2 diabetes. Their indications, contraindications and instructions are different.

Read the weight-loss tablet comparison and Orlistat versus GLP-1 comparison for context, not as a substitute for a prescriber’s assessment.