Does Wegovy work as well as Mounjaro for weight loss?

How the SURMOUNT-5 trial compared the two medicines directly

For years the comparison between Wegovy and Mounjaro relied on placing two separate trial populations side by side, a method statisticians are rightly cautious about, because the patient groups, study designs and timelines differed. SURMOUNT-5 changed that. It was a randomised, open-label trial enrolling 751 adults with obesity, without type 2 diabetes, and pitting tirzepatide directly against semaglutide 2.4mg over 72 weeks.

The result: tirzepatide produced greater average weight loss. At the highest tolerated doses, the gap was clinically meaningful, not just a rounding difference. NICE's appraisal of tirzepatide (TA1026) also notes that indirect comparisons across the trial programme favour tirzepatide, which informed the committee's recommendation.

One misconception worth clearing up gently: some readers assume the newer medicine is always the better one. Recency is not a reliable guide here. What matters is mechanism, dose and individual response, and those are exactly the things a prescriber weighs up. If you're trying to decide whether Mounjaro or Ozempic is the right starting point for you, that guide walks through the key considerations in plain terms. If you want to explore how the two medicines compare more broadly, our full Wegovy vs Mounjaro guide covers the clinical picture in detail.

Does the newer Wegovy 7.2mg dose narrow the gap?

Possibly, yes. In January 2026 the MHRA approved a 7.2mg maintenance dose of semaglutide for use with Wegovy, and on 14 April 2026 approved a dedicated single-dose 7.2mg pen. Trials at 7.2mg reported average weight loss of around 20.7% over 72 weeks, approaching results seen with tirzepatide 15mg. That is a meaningful narrowing compared with the 2.4mg data from the STEP 1 trial, which showed roughly 15% average reduction over 68 weeks, as the NHS semaglutide medicines page summarises.

The 7.2mg dose is licensed for adults with BMI 30 or above, not for lower thresholds. It also requires titrating up from 0.25mg in the standard way; no patient skips straight to the highest dose. Whether 7.2mg is available and suitable for any individual is a clinical decision, not a menu choice. Our Wegovy v Mounjaro overview explores this developing picture further.

What that means practically: the performance gap between the two medicines has narrowed at the highest approved doses for Wegovy, but tirzepatide's advantage in SURMOUNT-5 was established against the 2.4mg comparator. If you're wondering whether Wegovy works as well as Mounjaro at these newer, higher doses, we look at that question in detail, including what the emerging data actually show. Longer-term head-to-head data at 7.2mg are still emerging.

Does mechanism explain the difference?

Mounjaro is a dual GIP and GLP-1 receptor agonist, it activates two gut-hormone pathways linked to appetite regulation and blood-sugar control. Wegovy acts on the GLP-1 pathway only. Whether activating both pathways is the main driver of the performance difference is an active area of research rather than a settled fact, but it is the leading mechanistic hypothesis. How Wegovy and Mounjaro work compares the two mechanisms if you'd like more detail on that.

What is settled: both medicines slow gastric emptying, reduce appetite and are taken once weekly by subcutaneous injection. Their licensed indications for weight management in the UK are similar, adults with BMI 30 or above, or 27 or above alongside a weight-related condition such as hypertension or dyslipidaemia. Ethnic-background thresholds are 2.5 kg/m² lower under UK guidance. Neither is a better fit for every person; response varies between individuals even within the same trial.

Which is right for you) and how our prescribers approach that question

Trial averages describe populations. Individual responses to either medicine can fall well above or below the published figures, shaped by genetics, diet, activity, dosing tolerance and existing health conditions. A patient who loses 8% on tirzepatide might have lost 12% on semaglutide, or vice versa, the data cannot predict individual outcomes. Our guide to switching between Mounjaro and Wegovy explores what happens when one medicine doesn't deliver the expected results.

Which suits you is a clinical decision our prescribers make with you, drawing on your full medical history, current medications, BMI and any relevant conditions. Both are prescription-only medicines requiring that assessment. If you're ready to have that conversation, start your free consultation and a GPhC-registered prescriber will review it the same day.