‘Forgotten’ Drug Mysimba Offers Alternative to GLP-1 Weight Loss Treatments

By the Editorial Team · Tuesday, September 29, 2026

Mysimba, an older oral weight-loss medication combining naltrexone and bupropion, is gaining attention as a lower-cost alternative to popular GLP-1 injectable treatments like Wegovy and Mounjaro. Its distinct appetite-suppressing mechanism and affordability may offer a useful option for certain patients, although its modest efficacy and side effects require careful clinical monitoring.

An older weight-loss medication called Mysimba is receiving renewed attention as an alternative to popular GLP-1 treatments such as Wegovy and Mounjaro, according to medical experts. While GLP-1 drugs have gained widespread popularity in the UK, driven in part by high-profile endorsements, Mysimba remains relatively overlooked despite its potential benefits and lower cost.

Mysimba is a prescription-only pill that contains a combination of naltrexone and bupropion. It is licensed for use in individuals who are obese or overweight with associated health issues, including mild obesity and conditions such as high blood pressure. Unlike GLP-1 therapies, which primarily involve injections, Mysimba is administered orally and is available through private clinics in the UK.

Clinical trial data indicate that Mysimba users typically experience weight loss of approximately 8 percent of their initial body weight. This is modest compared with the up to 22 percent reduction sometimes reported with high-dose Mounjaro, a GLP-1 drug. Despite this difference in efficacy, experts highlight Mysimba’s distinct mechanism of action: it works by affecting multiple brain systems that regulate hunger, fullness, energy intake, and reward responses related to food, thereby helping to suppress appetite and reduce cravings.

Cost considerations further differentiate the treatments. Mysimba is available at about £115 per month at retail pharmacies such as Superdrug, while GLP-1 medications like Mounjaro range from around £179 to £339 monthly. The lower price point may make Mysimba a more accessible option for certain patients, particularly those with less severe obesity or related conditions.

Professor Alexander Miras of the University of Ulster suggests that Mysimba could be used either instead of or alongside GLP-1 drugs to tailor treatment to individual patient needs. However, combined use may be limited by the higher overall costs.

While GLP-1 treatments have shown strong efficacy and are generally well tolerated, they do not work for everyone. Mysimba offers an alternative pathway, though it carries its own risks. Side effects of Mysimba can include headaches, irritability, and insomnia, with rare but serious adverse events such as suicidal thoughts documented. Given these concerns, clinicians caution that patient monitoring is essential.

The current enthusiasm for GLP-1 therapies has sparked calls among experts for broader innovation in obesity treatment. Advocates emphasize the importance of offering a range of pharmaceutical options to meet the diverse needs of patients, as no single medication is suitable for all individuals.

In sum, Mysimba represents a less prominent but potentially valuable tool in addressing obesity, particularly for those who may benefit from a more affordable or different therapeutic approach than that provided by GLP-1 drugs.

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