Mounjaro®
Starting from £179.99/mo
Start journey Learn moreHow to think through the switch, and what the evidence says about each medicine
Why the milligram numbers don't translate directly
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, it activates two gut-hormone pathways simultaneously. Wegovy (semaglutide) targets only the GLP-1 receptor. Because the underlying mechanisms differ, the dose numbers carry different meanings and cannot be treated as a conversion table.
Mounjaro's schedule runs from 2.5mg up to 15mg in 2.5mg steps, titrated roughly every four weeks by your prescriber. At 5mg you are two steps in, past the tolerability starter dose but not yet at mid-range. Wegovy's schedule runs from 0.25mg to a standard maintenance dose of 2.4mg weekly; a 7.2mg single-dose pen was approved by the MHRA in April 2026 for adults with a BMI of 30 or above, extending the upper option further. If you are wondering whether 0.5mg Wegovy is the same as 5mg Mounjaro, the gap in numbers reflects structural differences in the molecules and their binding affinities, not potency in any simple sense.
For a fuller look at how these two dose ladders sit alongside each other, the Mounjaro-to-Wegovy dose conversion guide on this site covers the full schedule comparison. The 5mg Mounjaro equivalent in Wegovy terms page explores the clinical framing of this specific step in more detail.
What the evidence shows for each medicine at this stage of treatment
In the SURMOUNT-1 trial (2,539 adults with obesity, 72 weeks) tirzepatide at its highest dose produced an average body-weight reduction of around 20 to 21%, with some analyses reaching 22.5%, as published in the New England Journal of Medicine. The STEP 1 trial for semaglutide 2.4mg showed an average reduction of around 15% over 68 weeks. In the 2025 SURMOUNT-5 head-to-head trial (72 weeks, 751 adults with obesity), tirzepatide produced greater average weight loss than semaglutide 2.4mg, though the 7.2mg Wegovy dose was not part of that comparison.
Neither set of figures tells you what you, specifically, will experience. Trial averages smooth over a wide spread of individual responses, and the question of which medicine suits your physiology, your tolerance of side effects, and your clinical picture is one a prescriber is placed to answer rather than a headline percentage. The broader Wegovy vs Mounjaro comparison covers both medicines' evidence profiles in full.
| Feature | Mounjaro 5mg | Wegovy (semaglutide) |
|---|---|---|
| Active ingredient | Tirzepatide | Semaglutide |
| Receptor action | Dual GIP + GLP-1 | GLP-1 only |
| Position on schedule | Step 2 of 6 (titration continues) | 5mg has no Wegovy equivalent; closest maintenance is 1.7–2.4mg weekly |
| Average weight loss (trial) | Up to ~20–21% at 15mg maintenance [NEJM SURMOUNT-1] | ~15% at 2.4mg; ~20.7% at 7.2mg reported |
| UK licence | Weight management + type 2 diabetes | Weight management (+ cardiovascular indication) |
| Administration | Once-weekly injection, KwikPen | Once-weekly injection, pre-filled pen |
Both carry a Black Triangle (▼) designation, meaning the MHRA requires additional monitoring. Side-effect profiles overlap considerably, nausea, vomiting, constipation and fatigue are common to both, typically most noticeable after starting or after a dose step, and often settling within a couple of weeks. The NHS tirzepatide page and the NHS semaglutide page both set out the full side-effect profiles for patients.
The practical decision: staying on 5mg Mounjaro or moving to Wegovy
People consider this switch for several reasons: supply issues with one medicine, a prescriber's clinical recommendation, a preference for the injection format, or a view on how their response to tirzepatide has been so far. None of those factors alone determines the right answer.
If you are on 5mg Mounjaro and considering Wegovy, a prescriber will typically want to know how you have responded at 2.5mg and 5mg, what side effects you have experienced, and what your current weight trend looks like. The starting point on Wegovy after a switch is a clinical judgement, not a formula. Starting too high risks a difficult adjustment period; starting too low can feel like lost ground.
It is also worth factoring in cost. The private price of each varies by dose and provider, and neither medicine comes cheaply at full titration. The price difference between Mounjaro and Wegovy page gives an honest picture of current UK market ranges. Our prescribers at nume discuss cost considerations as part of the consultation, the school-run deadline aside, most people prefer to settle a plan rather than chase it across multiple calls. That is why the consultation is free and unhurried.
For a more direct comparison at a specific dose step, the Wegovy 1mg vs Mounjaro 5mg page addresses one of the most frequently asked equivalence questions. Which treatment suits you is a clinical decision our prescribers make with you, not one any comparison page can make for you.
How to explore a switch through nume
Switching between GLP-1 medicines requires the same rigorous assessment as starting from scratch, your consultation is reviewed in full by a GPhC-registered prescriber on the same day you submit it. Transfer patients provide evidence of their current treatment and most recent dose, and any dose change is assessed individually rather than applied automatically.
Our pharmacy holds GPhC premises registration 9012878, verifiable directly at the GPhC pharmacy register. Medicines are sourced through the licensed UK supply chain. If you want to explore whether Wegovy or continuing with Mounjaro is the right direction, the place to start is a free consultation with our prescribers. You can also read more about our weight-loss treatment options or meet the clinical team behind the service.
Looking to start your weight loss journey?
Take a quick eligibility quiz to explore your options and see how we can support you.