Mounjaro®
Starting from £179.99/mo
Start journey Learn moreThe clinical picture: what the sales surge is really telling you
The biggest myth: one of these is simply better
Ask around online and you will find confident verdicts, Mounjaro wins, Wegovy is old news, or vice versa. The reality is more nuanced. Both medicines are licensed by the MHRA for adults with a BMI of 30 or above, or 27 and above with at least one weight-related condition. Both slow gastric emptying, reduce appetite and support meaningful weight loss. The difference that matters most is mechanism: Wegovy activates a single gut-hormone receptor (GLP-1), while Mounjaro activates two (GLP-1 and GIP). Whether that dual action translates into the right outcome for you depends on your health profile, your tolerance and your prescriber's clinical judgement, not on which pen sold more units last quarter.
The sales story is genuine, though. Both medicines have seen extraordinary demand in the UK since their respective NICE approvals, and that demand has at times outpaced supply. If you want the fuller picture of how the two medicines sit side by side, our guide to the Mounjaro and Wegovy weight loss comparison works through the mechanism differences in depth, alongside the detailed Mounjaro and Wegovy comparison on this site.
What the trial data actually says, a fair reading
Head-to-head evidence matters here, and we have some. The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, compared tirzepatide directly with semaglutide 2.4mg over 72 weeks in adults with obesity but without diabetes. Tirzepatide produced a greater average reduction in body weight. That is a real finding from a rigorous trial, but it compares the standard 2.4mg maintenance dose of Wegovy with tirzepatide. Since then, the MHRA approved a higher Wegovy maintenance dose of 7.2mg (including a dedicated single-dose pen, approved 14 April 2026), with trials reporting around 20.7% average weight loss over 72 weeks, a figure that narrows the gap considerably.
Earlier landmark trials give useful context too. SURMOUNT-1 (tirzepatide, published in the New England Journal of Medicine) showed an average body-weight reduction of around 20 to 21% at the highest dose over 72 weeks. STEP 1 (semaglutide 2.4mg) showed approximately 15% average reduction over 68 weeks. The table below summarises the key figures.
| Factor | Mounjaro (tirzepatide) | Wegovy injection (semaglutide) |
|---|---|---|
| Mechanism | Dual GIP and GLP-1 receptor agonist | GLP-1 receptor agonist |
| Average weight loss in pivotal trial | ~20–21% at 15mg (SURMOUNT-1, 72 weeks) | ~15% at 2.4mg (STEP 1, 68 weeks); ~20.7% at 7.2mg |
| Head-to-head result | Greater average loss vs semaglutide 2.4mg (SURMOUNT-5, NEJM 2025) | 7.2mg dose narrows the gap significantly |
| UK licence (weight management) | Yes (MHRA licensed; NICE recommended (TA1026) | Yes) MHRA licensed; NICE recommended (TA875) |
| Dose form | Once-weekly subcutaneous injection (KwikPen) | Once-weekly subcutaneous injection; oral tablet also licensed (June 2026) |
| Available without NHS criteria at nume | Yes, subject to clinical assessment | Yes, subject to clinical assessment |
Numbers are from the named trials and from NICE's published guidance; they describe average results in trial populations, not individual predictions.
A note on Ozempic, it is not the same as Wegovy
Ozempic is also semaglutide and is made by the same manufacturer, Novo Nordisk. But it is licensed in the UK for type 2 diabetes management, not for weight loss. If you have seen it discussed in the same breath as Wegovy and Mounjaro in the context of weight management, the MHRA is clear: Ozempic should not be prescribed for weight loss, and doing so is off-label use that the regulator does not endorse. If someone is trying to point you toward Ozempic for weight loss, that is worth pausing on. The licensed options are Wegovy and Mounjaro, and you can read more about how semaglutide and tirzepatide compare as the active ingredients behind those brands.
Similarly, for anyone wondering about combining medicines: taking Ozempic and Mounjaro together is not a recognised or licensed approach, and the clinical reasons why are covered separately, the short answer is that a prescriber would not advise it.
How to make sense of this if you are trying to choose
It is genuinely understandable to feel overwhelmed by this. You may have read one article saying Mounjaro is streets ahead, another saying Wegovy's new higher dose changes everything, and a third that is really just an advert dressed up as a comparison. The honest position is that both medicines are effective, both are licensed and regulated in the UK, and your health history (not a trial average) is what a good prescriber weighs up. NICE's appraisal of tirzepatide (TA1026) and its appraisal of semaglutide (TA875) both confirm clinical and cost effectiveness within their respective NHS criteria, which gives you a sense of the regulatory confidence behind each.
At nume, a real clinician reads your consultation answers and considers both options in light of your medical background. If you want to explore what a clinical view on your specific situation might look like, the free consultation is the place to start. There is no obligation and no algorithm deciding in advance. The Wegovy vs Mounjaro page on this site also breaks down practical considerations (injection technique, dose schedules, what to expect in the first weeks) if you want to keep reading before you decide. And if cost context is part of your thinking, how much Wegovy and Mounjaro cost relative to each other is covered in its own right. Which medicine suits you is a clinical decision our prescribers make with you.
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