Mounjaro®
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Start journey Learn moreWhat the trial data and NICE guidance actually show about these two dose schedules
What the SURMOUNT and STEP trials tell us about each medicine's ceiling
The clearest place to start is the headline trial results, because they set the ceiling each medicine has been demonstrated to reach. In SURMOUNT-1 (a 72-week randomised trial published in the New England Journal of Medicine) adults without diabetes taking the highest licensed dose of tirzepatide (Mounjaro 15mg) lost an average of around 20–21% of their body weight. Across earlier STEP trials, semaglutide 2.4mg (Wegovy's standard maintenance dose) produced an average reduction of roughly 15% over 68 weeks. Those figures are not directly comparable (different populations, different trial designs) but they give a practical sense of the gap at maximum licensed doses.
The closest we have to a head-to-head is SURMOUNT-5, published in the New England Journal of Medicine in 2025, which ran tirzepatide against semaglutide 2.4mg in adults with obesity over 72 weeks. Tirzepatide produced greater average weight loss in that trial. NICE's appraisal of tirzepatide (TA1026) noted that indirect comparisons also favour tirzepatide, while acknowledging the evidence base continues to grow. Wegovy 7.2mg, approved by the MHRA in early 2026, narrows that gap (trials reported around 20.7% average weight loss at the higher semaglutide dose) though the two remain on different footing in terms of licensed schedules.
A question our prescribers hear most weeks is whether a particular Mounjaro dose is "the same as" a particular Wegovy dose, and our page on what Wegovy 1mg corresponds to on the Mounjaro schedule explores exactly why that comparison is more nuanced than it first appears. The honest answer is that the schedules were not designed against each other, so the phrasing of a dose equivalent is somewhat misleading from the outset.
How the dose ladders sit side by side
The table below sets out the licensed titration steps for each medicine and the broad evidence context at each level. It is a factual reference, not a conversion guide: a prescriber decides starting dose, titration pace and any changes.
| Mounjaro (tirzepatide) | Wegovy injection (semaglutide) | Notes |
|---|---|---|
| 2.5 mg (starter, 4 weeks) | 0.25 mg (starter, 4 weeks) | Both starter doses are designed for tolerability, not therapeutic effect |
| 5 mg | 0.5 mg | First titration step; body adjusting to the medicine |
| 7.5 mg | 1.0 mg | Mid-titration; GI side effects often ease here |
| 10 mg | 1.7 mg | Approaching maintenance territory for some patients |
| 12.5 mg | 2.4 mg (standard maintenance) | STEP 1 trial data: ~15% average weight loss at 68 weeks [NEJM STEP 1] |
| 15 mg (maximum) | 7.2 mg (higher maintenance, MHRA-approved 2026) | SURMOUNT-1: ~20–21% average; Wegovy 7.2mg trials: ~20.7% average |
Looking at that table, it becomes clear why the idea of a dose equivalent is appealing but imprecise. Both medicines start at a tolerability dose and step up roughly every four weeks, but the numerical jumps on each ladder mean nothing in isolation, 5mg tirzepatide and 0.5mg semaglutide are both early titration steps, but they cannot be called equivalent in any pharmacological sense. If you are thinking about switching between the two medicines, the conversion question becomes even more clinical: it depends on how long you have been on your current treatment, how much weight you have lost, and how well you have tolerated it.
Where the evidence puts each medicine against NICE eligibility thresholds
Both medicines are recommended by NICE for adults meeting specific BMI and comorbidity criteria, though the criteria differ. NICE TA1026 recommends tirzepatide for adults with a BMI of 35 or above plus at least one weight-related comorbidity, with thresholds 2.5 kg/m² lower for certain ethnic backgrounds. NICE TA875 recommends semaglutide under stricter service conditions, through a specialist weight management service, for a maximum of two years. Private eligibility under each medicine's licence is broader: BMI of 30 or above, or 27 or above with a qualifying weight-related condition, with a prescriber assessing the full picture.
The practical implication for someone comparing the two medicines is that the results evidence favours tirzepatide at maximum doses, but suitability depends on individual health history, existing medications and tolerability, not on which medicine has the bigger average trial number. If you want to explore the broader comparison between Wegovy and Mounjaro, including side-effect profiles and cost context, that page covers both in more depth.
Which medicine suits you is a clinical decision our prescribers make with you, taking into account the full picture, not the trial averages alone.
What this means for a consultation at nume
When you start a free consultation through our treatment page, a GPhC-registered Independent Prescriber reviews your answers the same day. If you are transferring from one medicine to the other, or asking about dose equivalence because you are weighing up which to start, the prescriber works through your medical history, your current weight and any previous treatment evidence before making a recommendation. There is no algorithm making that call. You can also read more about our clinical team if you want to know who is reviewing your case.
For those specifically thinking about where individual doses sit in relation to each other, our pages on Mounjaro and Wegovy equivalent doses and on what 5mg Mounjaro corresponds to on the Wegovy schedule go into more detail at the individual step level. If cost is part of the decision, our page comparing the two on price sets out what private treatment typically involves for each.
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