Ozempic and Mounjaro Compared: Licences, Evidence and What the Trials Show

What the clinical evidence says, starting from the trials, not the headlines

NICE published its appraisal of tirzepatide (Mounjaro) in December 2024 and updated it in September 2025, citing the SURMOUNT-1 trial as central evidence. In that 72-week study, adults taking tirzepatide at the highest dose achieved an average body-weight reduction of around 20–21%, with some analyses reaching approximately 22.5%. The SURMOUNT programme involved thousands of adults across its trials. For semaglutide at the 2.4mg weekly dose (the weight-management formulation, Wegovy), the STEP 1 trial reported an average reduction of around 15% over 68 weeks, as assessed in the STEP 1 paper published in the New England Journal of Medicine. The SURMOUNT-5 head-to-head trial, published in 2025, directly compared tirzepatide and semaglutide 2.4mg; tirzepatide produced the greater average weight reduction over 72 weeks in adults with obesity and no diabetes.

Ozempic does not feature in any of this weight-management trial comparison. It uses the same active ingredient as Wegovy (semaglutide) but at different doses and under a different licence. If you are weighing up how Ozempic and Mounjaro differ across the key metrics, it is worth understanding that comparing them for weight loss is, strictly speaking, a category error: one product is not authorised for that purpose. The comparison that is clinically meaningful in the UK is Wegovy versus Mounjaro, and even there the choice depends on individual health factors, not trial averages alone.

If you want to go deeper on that specific comparison, our page on Wegovy versus Mounjaro works through the evidence in detail.

Ozempic's UK licence and why it is not a weight-loss medicine here

The MHRA licenses Ozempic for the management of type 2 diabetes in adults, not for weight management. This is not a grey area. The NHS medicines page for semaglutide sets this out plainly, as does MHRA public guidance on GLP-1 medicines. Prescribing Ozempic specifically for weight loss in a person without diabetes would be off-label use; any legitimate UK prescriber working within their regulatory obligations will follow the authorised indications.

The weight-loss version of semaglutide is Wegovy, same molecule, different dose and a specific weight-management marketing authorisation. Novo Nordisk also received MHRA approval in June 2026 for an oral semaglutide tablet (Wegovy tablets) for weight management, making it the first licensed oral GLP-1 medicine for this purpose in the UK. Rybelsus, the existing oral semaglutide tablet, is licensed for type 2 diabetes at lower doses and is not a weight-loss medicine.

So when someone asks whether Ozempic and Mounjaro are the same thing, the short answer is no: different molecules, different mechanisms, different licences. For weight management in the UK, the relevant products are Mounjaro and Wegovy. Our prescribers discuss both options during consultations, and the page on whether Mounjaro and Ozempic are the same explores the chemistry in more detail if that is useful.

A factual comparison: Ozempic, Wegovy and Mounjaro side by side

The table below covers the key factual differences. Numbers drawn from published trial data and UK regulatory sources.

The cost difference between Mounjaro and Wegovy is a question we hear often; our page on the price difference between Mounjaro and Wegovy gives current context on what drives those figures. Neither medicine is available without a prescription, and neither should be sourced from sellers who offer them without a clinical assessment, the MHRA has warned publicly about counterfeit weight-loss pens sold online, some containing insulin rather than the stated active ingredient.

What is actually licensed for weight loss in the UK, and how to access it

If your goal is weight management rather than diabetes treatment, the two medicines with UK authorisation for that purpose, and dispensed through a regulated private pharmacy like nume, are Mounjaro and Wegovy. NICE's appraisal of tirzepatide (TA1026) recommends Mounjaro for adults with a BMI of 35 or above and at least one weight-related health condition, with lower BMI thresholds applicable for some ethnic backgrounds under UK guidance. Wegovy sits under a separate NICE recommendation (TA875) with its own eligibility criteria.

Private prescribing through a regulated pharmacy sits outside those NHS eligibility bands. Adults with a BMI of 30 or above (or 27 with a weight-related condition such as high blood pressure or obstructive sleep apnoea) may be suitable for private treatment, subject to a full clinical assessment. The prescriber looks at the whole picture: medical history, current medicines, any contraindications, and which product is the better clinical fit for that individual.

Which of these two medicines suits you is not a decision the trial data makes on your behalf. It is a clinical decision our prescribers make with you. If you would like that conversation, check your eligibility and start your free consultation. You can also read more about how Wegovy and Mounjaro compare for weight management, or learn more about the treatment options we offer. Romanian-speaking patients looking for guidance in their own language can find a detailed breakdown on our ozempic sau mounjaro page.