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Understanding Mysimba Weight Loss Tablets: Efficacy, Dosing and UK Availability

Published: 16 August 2026

Mysimba weight loss tablets are a dual-action prescription medication combining naltrexone and bupropion, designed to support weight management in adults with a BMI of 30 or above, or 27 or above with weight-related health conditions. Approved by the MHRA and available through UK-registered prescribers, Mysimba works by targeting appetite control and reward pathways in the brain. At Cured Pharmacy, Mysimba is available from £124.99, subject to clinical assessment by our UK-registered prescribers.

How Mysimba Weight Loss Tablets Work in the Body

Mysimba weight loss tablets contain two active ingredients: naltrexone hydrochloride 8mg and bupropion hydrochloride 90mg. This combination targets the hypothalamus and mesolimbic reward system, areas of the brain involved in appetite regulation and food cravings[1]. Naltrexone, traditionally used for addiction management, blocks opioid receptors, while bupropion, a dopamine and norepinephrine reuptake inhibitor, enhances satiety signals.

Clinical trials have demonstrated that this dual mechanism can help reduce caloric intake and increase feelings of fullness. The COR-I trial showed that patients taking Mysimba alongside a reduced-calorie diet and increased physical activity achieved an average weight loss of 8.1% of their initial body weight over 56 weeks, compared to 4.9% in the placebo group[2]. It's important to note that Mysimba is most effective when combined with lifestyle modifications, including a balanced diet and regular exercise.

The medication does not work by blocking fat absorption or increasing metabolism directly. Instead, it modulates neurotransmitter activity to help patients feel satisfied with smaller portions and resist cravings for high-calorie foods. This neurochemical approach makes Mysimba particularly suitable for individuals who struggle with emotional eating or reward-driven food behaviours.

Mysimba Weight Loss Tablets Dosing and Titration Schedule

The dosing protocol for Mysimba weight loss tablets follows a gradual titration schedule to minimise side effects, particularly nausea and headache. Patients begin with one tablet each morning for the first week, then increase to one tablet twice daily (morning and evening) in week two. By week three, the dose increases to two tablets in the morning and one in the evening, reaching the full maintenance dose of two tablets twice daily (four tablets total per day) from week four onwards[3].

This stepped approach allows the body to adjust to the medication's effects on neurotransmitter levels. Each tablet contains 8mg naltrexone and 90mg bupropion, meaning the full daily dose at maintenance is 32mg naltrexone and 360mg bupropion. Tablets should be swallowed whole with water and can be taken with or without food, though taking them with meals may reduce nausea in some patients.

If a patient has not achieved at least 5% weight loss after 16 weeks on the full dose, prescribers will typically discontinue treatment, as continued use is unlikely to produce clinically meaningful results. This stopping rule is based on NICE guidance and ensures that patients only continue with treatments that demonstrate efficacy for their individual circumstances[4].

Missed Dose Guidance

If you miss a dose of Mysimba weight loss tablets, take it as soon as you remember, unless it's close to your next scheduled dose. Never double up to make up for a missed dose, as this increases the risk of side effects including seizures. If you miss multiple doses, contact your prescriber before resuming treatment, as you may need to restart the titration schedule to ensure safety.

Expected Results with Mysimba Weight Loss Tablets

In clinical trials, patients using Mysimba weight loss tablets achieved significantly greater weight loss than those on placebo when combined with lifestyle interventions. The COR-II trial, which included over 1,400 participants, found that 50% of patients on Mysimba lost at least 5% of their baseline weight, and 28% achieved weight loss of 10% or more over 56 weeks[2]. These results were observed in individuals adhering to a reduced-calorie diet and increasing physical activity by at least 150 minutes per week.

Weight loss typically begins within the first four weeks of reaching the maintenance dose, though individual responses vary. Patients with higher baseline BMI or those who engage more consistently with dietary and exercise modifications tend to see more pronounced results. It's crucial to understand that Mysimba is not a standalone solution—clinical trials required participants to reduce daily caloric intake by 500 kcal and increase physical activity, highlighting the importance of comprehensive lifestyle change.

Prescribers assess progress at 16 weeks and 24 weeks. If weight loss plateaus or reverses, adjustments to diet, exercise, or medication may be necessary. Some patients continue Mysimba for up to two years under medical supervision, though long-term safety and efficacy data beyond this period are limited.

Factors Influencing Response

Response to Mysimba weight loss tablets can be influenced by genetic factors affecting dopamine and opioid receptor sensitivity, adherence to the titration schedule, concurrent medications, and baseline eating behaviours. Patients with binge-eating tendencies or strong reward-driven eating patterns may experience more significant appetite suppression than those whose weight gain is primarily due to metabolic or hormonal factors.

Common Side Effects of Mysimba Weight Loss Tablets

The most frequently reported side effects of Mysimba weight loss tablets include nausea (affecting up to 32% of patients), constipation (19%), headache (18%), vomiting (10%), and dizziness (10%)[5]. These effects are typically most pronounced during the titration phase and often diminish as the body adjusts to the medication. Taking tablets with food and staying well-hydrated can help manage gastrointestinal symptoms.

Less common but more serious side effects include increased blood pressure and heart rate, which is why blood pressure should be monitored regularly during treatment. Mysimba carries a boxed warning in some regions regarding the potential for suicidal thoughts and behaviours, particularly in patients with a history of depression or psychiatric conditions. Any mood changes, agitation, or unusual thoughts should be reported to a healthcare provider immediately[3].

Mysimba is contraindicated in patients with uncontrolled hypertension, seizure disorders, eating disorders (current or historical), those undergoing abrupt discontinuation of alcohol or benzodiazepines, and individuals taking monoamine oxidase inhibitors (MAOIs). It should not be used during pregnancy or breastfeeding. A full medical history and medication review are essential before starting Mysimba weight loss tablets.

Mysimba Weight Loss Tablets vs Other UK Weight Loss Treatments

When comparing Mysimba weight loss tablets to other prescription weight loss options available in the UK, several key differences emerge. Orlistat (available as generic, Xenical, or Alli) works by blocking fat absorption in the gut, leading to an average weight loss of 3-5% over 12 months[6]. While effective, Orlistat can cause gastrointestinal side effects such as oily stools and urgency, particularly when dietary fat intake is not carefully controlled.

GLP-1 receptor agonists such as Wegovy (semaglutide) and Saxenda (liraglutide) are injectable medications that slow gastric emptying and enhance satiety. Clinical trials show that semaglutide can produce average weight loss of 12-15% over 68 weeks, making it one of the most effective pharmacological options currently available[7]. However, these medications require weekly or daily injections and may not be suitable for patients uncomfortable with self-injection.

Mysimba offers a tablet-based alternative for patients who prefer oral medication and may be particularly effective for those with reward-driven eating behaviours or emotional eating patterns. The choice between treatments depends on individual medical history, BMI, comorbidities, lifestyle preferences, and response to previous weight loss attempts. All prescription weight loss medications available through Cured Pharmacy require clinical assessment by a UK-registered prescriber to ensure suitability and safety.

Combination Approaches

Some patients may benefit from sequential or combination approaches, such as starting with Orlistat and transitioning to Mysimba weight loss tablets if results plateau, or using Mysimba alongside structured behavioural therapy programmes. Your prescriber can discuss personalised treatment strategies based on your weight loss goals, medical history, and previous treatment responses.

Buying Mysimba Weight Loss Tablets Online at Cured Pharmacy

At Cured Pharmacy, Mysimba weight loss tablets are available from £124.99, with transparent pricing displayed before you begin your online consultation. As a UK-registered pharmacy (GPhC 9012511) under the supervision of Superintendent Pharmacist Tarun Kumar (GPhC 2233073), we provide a safe, regulated pathway to access prescription weight loss treatments entirely online.

The process begins with a free online clinical assessment that takes under three minutes to complete. Our UK-registered prescribers review your medical history, current medications, weight loss goals, and any contraindications to determine if Mysimba weight loss tablets are suitable for you. If approved, your prescription is issued electronically and dispensed by our pharmacy team, with discreet next-day delivery available across the UK.

We source only genuine, UK-licensed medicines and provide ongoing support throughout your treatment journey. New patients can Save £20 on their first order using code Weightlossnew. All consultations are confidential, and our clinical team is available by phone (+44 116 4646009) to answer questions about dosing, side effects, or treatment adjustments. Mysimba, like all prescription medications, is subject to prescriber approval and requires regular monitoring to ensure safety and efficacy.

Scientific References

1. Greenway, F. L., Fujioka, K., Plodkowski, R. A., Mudaliar, S., Guttadauria, M., Erickson, J., ... & COR-I Study Group. (2010). Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet, 376(9741), 595-605. [accessed 16 August 2026]
2. Apovian, C. M., Aronne, L., Rubino, D., Still, C., Wyatt, H., Burns, C., ... & COR-II Study Group. (2013). A randomized, phase 3 trial of naltrexone SR/bupropion SR on weight and obesity-related risk factors (COR-II). Obesity, 21(5), 935-943. [accessed 16 August 2026]
3. Electronic Medicines Compendium. (2023). Mysimba 8 mg/90 mg prolonged-release tablets - Summary of Product Characteristics (SmPC). Retrieved from https://www.medicines.org.uk/emc/product/2684/smpc [accessed 16 August 2026]
4. National Institute for Health and Care Excellence. (2014). Weight management: lifestyle services for overweight or obese adults (PH53). NICE guideline. [accessed 16 August 2026]
5. Hollander, P., Gupta, A. K., Plodkowski, R., Greenway, F., Bays, H., Burns, C., ... & COR-Diabetes Study Group. (2013). Effects of naltrexone sustained-release/bupropion sustained-release combination therapy on body weight and glycemic parameters in overweight and obese patients with type 2 diabetes. Diabetes Care, 36(12), 4022-4029. [accessed 16 August 2026]
6. Rucker, D., Padwal, R., Li, S. K., Curioni, C., & Lau, D. C. (2007). Long term pharmacotherapy for obesity and overweight: updated meta-analysis. BMJ, 335(7631), 1194-1199. [accessed 16 August 2026]
7. Wilding, J. P., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., ... & STEP 1 Study Group. (2021). Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine, 384(11), 989-1002. [accessed 16 August 2026]
8. NHS. (2026). Tirzepatide: a medicine to manage type 2 diabetes and treat obesity. https://www.nhs.uk/medicines/tirzepatide/ Accessed 16 August 2026.
9. NHS. (2026). Overweight and obesity in adults. https://www.nhs.uk/conditions/overweight-and-obesity/ Accessed 16 August 2026.
10. NHS England. (2026). Weight management injections. https://www.england.nhs.uk/ourwork/prevention/obesity/medicines-for-obesity/weight-management-injections/ Accessed 16 August 2026.

Information on this page is for educational purposes only and is not medical advice. All prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting any new medication.