Mounjaro®
Starting from £179.99/mo
Start journey Learn moreWhat the evidence and your prescriber's assessment actually guide here
You tried Wegovy, and now you're wondering whether Mounjaro would have been the better fit
That question is more common than you might think. A lot of people come to a switch (or a switch back) not because one medicine is objectively superior, but because individual biology doesn't always match population averages. You might have tolerated Wegovy well but found the weight loss plateaued earlier than expected. Or side effects were persistent in a way they weren't on Mounjaro. Or you simply felt better on tirzepatide and want to return to it, and if that sounds familiar, our guide on going back to Mounjaro from Wegovy walks through exactly what that involves.
The honest starting point is that SURMOUNT-5, a head-to-head trial published in the New England Journal of Medicine in 2025, found tirzepatide produced greater average weight reduction than semaglutide 2.4mg over 72 weeks in adults with obesity. That's a population-level finding, not a guarantee for any individual. Some people respond better to semaglutide than tirzepatide, and their reasons for switching back to Wegovy would be just as valid. The question is always what the evidence looks like for you, your weight trajectory, your side-effect profile, your dose history.
One thing worth knowing: Mounjaro is a dual GIP and GLP-1 receptor agonist, the only medicine of its kind licensed in the UK for weight management. Wegovy acts on the GLP-1 receptor alone. That difference in mechanism is one reason the two medicines can feel different in practice, and it's also why a prescriber wants a full picture before recommending a return.
What a prescriber actually checks before agreeing to switch you back
Switching between two prescription medicines isn't a self-service decision, even if both are in the same general class. When you ask to take Mounjaro after Wegovy, a prescriber will typically want to know: what dose of Wegovy you reached, how long you were on it, what your weight has done since, and what prompted the switch request. Transfer patients at nume are asked to provide evidence of their current treatment, this protects you as much as it protects the prescriber.
There is no mandatory medical washout between these two medicines; the decision is clinical rather than pharmacological. That said, starting back at 2.5mg Mounjaro (the tolerability starting dose) is the normal approach (even if you previously reached a higher dose) unless your prescriber has specific evidence to support resuming at a higher level. The titration schedule is there to let your system settle, and skipping it can increase the chance of side effects.
Your prescriber will also want to know whether you're using contraception. If you take the oral contraceptive pill, starting or restarting Mounjaro means adding a non-oral method for the first four weeks of treatment and for four weeks after each dose increase, because tirzepatide can reduce pill absorption. NHS England's guidance on weight-management injections covers this clearly and is worth reading before your consultation.
Mounjaro vs Wegovy: the key clinical facts side by side
This table summarises the licensed facts that matter when comparing the two medicines. It is not a recommendation; it's the information a prescriber uses alongside your individual history.
| Factor | Mounjaro (tirzepatide) | Wegovy (semaglutide) |
|---|---|---|
| Mechanism | Dual GIP + GLP-1 receptor agonist | GLP-1 receptor agonist |
| UK licence (weight) | BMI ≥30, or ≥27 with a weight-related condition | BMI ≥30, or ≥27 with a weight-related condition |
| Average weight loss in trials | ~20–21% at 15mg (SURMOUNT-1, NEJM) | ~15% at 2.4mg (STEP 1, NEJM); ~20.7% at 7.2mg |
| Head-to-head evidence | Greater average loss vs semaglutide 2.4mg (SURMOUNT-5, NEJM 2025) | 7.2mg narrows the gap substantially |
| Oral option | Injection only (KwikPen) | Injection and approved oral tablet (25mg) |
| Contraceptive pill interaction | Add non-oral method for 4 weeks on starting and after each dose increase | No equivalent evidence of reduced pill effectiveness |
Both carry a Black Triangle (▼) designation, meaning the MHRA collects additional safety data on an ongoing basis. The NICE technology appraisal for tirzepatide (TA1026) notes that if less than 5% weight loss is achieved after six months at the highest tolerated dose, continuation should be reviewed, a point that applies to Wegovy under TA875 too, and one that often prompts a switch conversation. If you're weighing up whether going from Mounjaro to Wegovy makes sense for your situation, that question is covered in detail in its own guide.
What switching back looks like in practice at nume
The process is straightforward. You complete a free consultation, our clinical team reviews your full treatment history (including your time on Wegovy) and your prescriber decides whether returning to Mounjaro is clinically appropriate. If approved, the prescription is written the same day. Orders placed before 12pm on a weekday are dispatched that afternoon and arrive the next working day by DPD, in plain packaging.
There is no subscription and no automatic renewal. Every repeat order goes through a fresh clinical review. If you have questions before starting, our FAQs cover the most common ones, and the team is available seven days a week. For anyone who has previously used Mounjaro and is now considering trying Wegovy after Mounjaro, that transition is also covered separately, alongside the full comparison of Wegovy vs Mounjaro for anyone who wants to weigh up both options before deciding.
Which medicine suits you is a clinical decision our prescribers make with you, not something to settle from a comparison table alone. Speak to our prescribers to start that conversation.
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