Mounjaro®
Starting from £179.99/mo
Start journey Learn moreThe four clinical factors shaping this switch decision
Why you'd be moving from a stronger mechanism to a different one
Mounjaro activates two receptors simultaneously: GIP and GLP-1. Wegovy acts on GLP-1 alone. That distinction matters when you're at 10mg, because at that dose tirzepatide is already producing meaningful dual-receptor stimulation that influences appetite, gastric emptying and energy regulation through both pathways. Switching to semaglutide means relying on a single pathway instead. The SURMOUNT-5 head-to-head trial, published in the New England Journal of Medicine in 2025, found that tirzepatide produced greater average weight reduction than semaglutide 2.4mg over 72 weeks in adults with obesity and no diabetes. That doesn't make Wegovy ineffective; STEP 1 showed around 15% average weight loss at the 2.4mg maintenance dose over 68 weeks. It does mean that switching mid-treatment requires a clear clinical reason rather than curiosity. A prescriber needs to understand what's driving the switch: side effects, supply, cost, a preference for the newer 7.2mg Wegovy pen, or something else. The mechanism difference is worth being honest about before you decide, and if you're specifically coming from the 7.5mg Mounjaro dose, our guide on switching from 7.5mg Mounjaro to Wegovy walks through what that step looks like in practice. You can read more about how Wegovy and Mounjaro compare on our dedicated comparison page.
What the dose conversion actually looks like at 10mg
There is no official, licensed dose-equivalence table between tirzepatide and semaglutide. A prescriber can't simply say '10mg Mounjaro equals X mg of Wegovy' and leave it there. What they can do is assess your current response, your tolerance history and your clinical picture, then recommend a starting point on the Wegovy schedule that they judge to be safe. In practice, patients switching from a mid-to-upper tirzepatide dose often do not restart Wegovy from 0.25mg if they've already demonstrated tolerance to GLP-1 stimulation, but that's a clinical judgement call, not a rule. The Mounjaro to Wegovy dose conversion question is one our prescribers work through carefully on a case-by-case basis. If you want a fuller picture of how to approach the Wegovy dose when making this switch, our page on switching from Mounjaro to Wegovy and what dose to start on covers the thinking behind that decision in detail. If you're interested in what the dose landscape looks like from the Wegovy side, the dosage considerations when switching from Mounjaro to Wegovy cover that in more detail. For context, Wegovy's standard schedule runs 0.25mg, 0.5mg, 1.0mg, 1.7mg and up to 2.4mg, with the newer 7.2mg dose now MHRA-approved for adults with a BMI of 30 or above.
Side effect profile and what might shift for you
Both medicines share a broadly similar gastrointestinal side effect profile: nausea, loose stools, constipation, indigestion and reduced appetite are common, particularly around dose increases. If gut side effects were the reason you're thinking of switching away from Mounjaro, that's a conversation to have honestly with a prescriber, because switching medicines isn't guaranteed to resolve them. The NHS medicines page for tirzepatide and the equivalent for semaglutide both list what to expect and when to seek urgent help. One safety point that applies to both: the MHRA issued a Drug Safety Update in January 2026 highlighting acute pancreatitis as a known, infrequent but potentially serious effect of GLP-1 medicines. Severe, persistent stomach pain radiating to the back is a reason to get same-day medical attention, whichever medicine you're taking. Any suspected side effects with either product can be reported directly at the MHRA Yellow Card scheme. Neither medicine is recommended during pregnancy or breastfeeding, and neither is licensed for under-18s.
A quick comparison of the two medicines at this stage of treatment
| Factor | Mounjaro 10mg (tirzepatide) | Wegovy up to 2.4mg / 7.2mg (semaglutide) |
|---|---|---|
| Receptor pathway | Dual: GIP + GLP-1 | Single: GLP-1 only |
| Average weight loss in trials | ~20–21% at 15mg over 72 weeks (SURMOUNT-1, NEJM) | ~15% at 2.4mg over 68 weeks; ~20.7% at 7.2mg (STEP trials) |
| Head-to-head evidence | SURMOUNT-5 (NEJM 2025): tirzepatide showed greater average loss than semaglutide 2.4mg | |
| Licensed UK BMI threshold | BMI ≥30, or ≥27 with a weight-related condition | 7.2mg pen: BMI ≥30 only; standard doses: ≥27 with condition |
| Pen / dose format | KwikPen (4 weekly doses per pen); 6 strengths | Pre-filled weekly pen; 7.2mg single-dose pen MHRA-approved April 2026 |
Figures are from clinical trials and MHRA-published information; individual results vary. Which medicine suits your situation is a clinical decision our prescribers make with you. If you've come from the opposite direction, the considerations around switching from Wegovy 2.4mg to Mounjaro cover that journey in full.
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