Does Wegovy work better than Mounjaro for some people?

What does the head-to-head evidence actually show about individual response?

The SURMOUNT-5 trial (published in the New England Journal of Medicine in 2025) compared tirzepatide (Mounjaro) directly against semaglutide 2.4 mg (Wegovy) over 72 weeks in 751 adults with obesity and no diabetes. On average, tirzepatide produced greater weight loss. That headline is real and it matters.

But averages hide a lot. Inside any trial population, a meaningful minority of participants respond substantially better to the comparison arm. That is not a flaw in the data; it is biology. GLP-1 receptor density, gut-hormone sensitivity, insulin resistance patterns and genetic variation all influence how well a given drug works for a given person. Semaglutide acts on GLP-1 receptors alone. Tirzepatide activates both GLP-1 and GIP receptors. For patients whose appetite and metabolic regulation is driven primarily through the GLP-1 pathway, a highly optimised single-agonist may outperform a dual one. Researchers are still mapping exactly who those people are, which is why the semaglutide-vs-tirzepatide individual-response question remains an active area of clinical interest.

NICE's appraisal of tirzepatide (TA1026) acknowledges that indirect comparisons favour tirzepatide on average weight loss — but it does not conclude that semaglutide is ineffective or inferior for specific patients. Both drugs remain NICE-recommended treatments. The clinical question is never purely statistical; it starts with the individual sitting in front of the prescriber.

Are there patient characteristics where Wegovy tends to suit better?

Clinical experience and the trial data together point to a few situations where semaglutide is often the considered choice, or becomes one after a switch.

Tolerability is the most common practical factor. Tirzepatide's dual-agonist mechanism can produce more pronounced early gastrointestinal effects in some patients: nausea, vomiting, constipation and reflux can be harder to manage at the lower starter doses. For people who have tried Mounjaro and found the side-effect burden unacceptable even after careful titration, semaglutide's GLP-1-only action sometimes sits more comfortably. That is not universal (plenty of people find the reverse) but it comes up regularly. You can read about what to expect when switching from Mounjaro to Wegovy if that is the conversation you are having with your prescriber.

Prior treatment history also matters. Patients who had a good response to semaglutide at a lower dose (for example on Ozempic for type 2 diabetes, a different licensed indication, covered separately in our Mounjaro vs Ozempic page) may continue to respond well when moved onto Wegovy's weight-management doses. And with the MHRA's approval of the 7.2 mg Wegovy pen in April 2026, the top-end dose available on semaglutide is now closer to tirzepatide 15 mg in terms of average outcomes, trial data at 7.2 mg reported around 20.7% average weight loss over 72 weeks, which narrows the gap seen at 2.4 mg considerably. The dose-ceiling picture has shifted the calculus for some patients since that approval.

Cardiovascular history is another clinical variable. Wegovy holds a UK authorisation for reducing major cardiovascular event risk in eligible adults, a licensed indication tirzepatide does not currently carry in the UK. Where that is a significant part of a patient's clinical picture, a prescriber may favour semaglutide for reasons beyond weight loss alone.

How do the two medicines compare side by side on the key numbers?

The table below draws on published trial data and approved UK product information. Numbers are trial averages; individual results vary, and these are not predictions for any particular patient.

For a deeper look at how these figures land in cost terms, the Mounjaro and Wegovy price comparison page covers UK private treatment pricing in full, including what a legitimate price should include.

So which one should you be on?

That is exactly the right question, and the honest answer is that it depends on your full clinical picture, not on a table or a trial average.

A prescriber weighing this will consider your BMI, any comorbidities (hypertension, sleep apnoea, type 2 diabetes, cardiovascular history), what you have tried before, how you tolerated it, your current medicines, and your lifestyle. If you are switching from an existing treatment, they will want evidence of your current dose and weight. Timing sometimes shapes this too: if you are starting treatment mid-month or just before a bank holiday, a prescriber may factor in dispatch schedules and when your first pen should realistically arrive.

The question of which of the two is clinically better does not have a single right answer, and any service that tells you otherwise is simplifying in a way that could genuinely matter to your health. Which suits you is a clinical decision our prescribers work through with you directly.

If you are ready to start that conversation, our clinical team reviews consultations the same day, you can check your eligibility and start your free consultation now. Or if you would like to read more about the treatment landscape first, our weight-loss treatments overview covers both options and how the process works.