Mounjaro®
Starting from £179.99/mo
Start journey Learn moreWhat the evidence, the licences and the practicalities actually tell you
How the two medicines compare at a glance
Mounjaro activates two gut-hormone receptors (GIP and GLP-1) making it the only dual-agonist weight-loss medicine currently licensed in the UK. Wegovy works on the GLP-1 receptor alone. Both slow gastric emptying, reduce appetite and are given as once-weekly subcutaneous injections. The mechanism gap matters because it partly explains the outcomes gap seen in trials.
The table below pulls together the key factual differences. Numbers come from the SURMOUNT-1 and STEP 1 trials (both published in the New England Journal of Medicine) and from NICE appraisals TA1026 and TA875.
| Factor | Mounjaro (tirzepatide) | Wegovy (semaglutide) |
|---|---|---|
| Mechanism | Dual GIP + GLP-1 agonist | GLP-1 agonist |
| Standard maintenance dose | Up to 15 mg weekly | 2.4 mg weekly (7.2 mg pen now MHRA-approved) |
| Average weight loss (landmark trial) | ~20–21% at 15 mg over 72 weeks (SURMOUNT-1) | ~15% at 2.4 mg over 68 weeks (STEP 1) |
| Head-to-head result | Greater average loss vs semaglutide 2.4 mg (SURMOUNT-5, 2025) | Narrowed gap at 7.2 mg dose (trial data emerging) |
| UK weight-loss licence | BMI ≥30, or ≥27 with a weight-related condition | BMI ≥30, or ≥27 with a weight-related condition |
| NICE recommendation | TA1026 (published Dec 2024) | TA875 (published Mar 2023) |
If you want more detail on how each medicine's titration schedule compares, the Wegovy vs Mounjaro comparison covers the practical dosing picture alongside the numbers above.
The decision you're actually trying to make
Most people arriving at this question are really asking one of two things: does the stronger-seeming medicine mean better results for me, and is it worth switching if I'm already on one of them? Both are fair. The frustration is understandable, you want a clear answer, and the internet keeps giving you marketing copy instead.
Here is the honest picture. On average, across large populations in controlled trials, tirzepatide produced greater weight loss. But averages describe groups, not individuals. Some people respond very well to semaglutide; others find tirzepatide's side-effect profile harder to tolerate, particularly during titration. Your starting weight, your existing conditions, your medication history and how your body responds all shape the outcome far more than trial headline figures alone.
The MHRA approved a 7.2 mg Wegovy pen in April 2026, and early trial data suggest it closes some of the gap with tirzepatide 15 mg, a question we explore in detail for anyone wondering whether Wegovy is as good as Mounjaro at this newer dose. You can read more about that specific question on the is Mounjaro stronger than Wegovy page, which looks at those numbers in more depth.
Side effects follow a broadly similar GI-led profile for both (nausea, constipation, indigestion and fatigue are the most commonly reported) and both carry a Black Triangle (▼) for additional MHRA monitoring. The NHS tirzepatide medicines page and the equivalent semaglutide page give a full breakdown of what to watch for with each.
What makes this a clinical decision, not just a comparison
Both Wegovy and Mounjaro are prescription-only medicines. No comparison article (including this one) can tell you which is right for you, because that assessment requires knowing things a search engine cannot: your GP record, your current medications, your weight history, any relevant conditions. A prescriber reviews all of that before any prescription is issued.
If you're considering switching from one to the other, that's a separate clinical question again. Patients moving from Wegovy to Mounjaro need evidence of their current treatment and a prescriber review of the right starting dose, and it is worth understanding whether Wegovy is the same as Mounjaro before assuming the transition is straightforward. The Mounjaro to Wegovy page covers what that process involves, and the which is stronger: semaglutide or tirzepatide page goes further into the mechanism behind the results difference.
At nume, every consultation is read by a named GPhC-registered Independent Prescriber before any treatment is issued. If you'd like to discuss which option fits your situation, speak to our prescribers via a free consultation, same-day clinical review, no waiting list, no subscription.
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