Switching to Wegovy: What to Expect When You Make the Change

The biggest myth: switching medicines means starting your weight loss over

Many people believe that moving from one GLP-1 medicine to another resets the clock entirely, that any progress disappears and they're back at square one. That's not accurate. The weight you've already lost stays lost. What changes is how the next medicine is introduced to your system.

Prescribers typically restart the dose titration from a lower level when switching, even if you were well-established on a higher dose of your previous treatment. This is a tolerability measure, not a verdict on your progress. Semaglutide's side-effect profile is similar to other GLP-1 medicines (nausea, changes in appetite, occasional digestive discomfort) but every person tolerates it slightly differently. A careful step-up gives your body time to adjust to the new compound.

The other common misconception is that all GLP-1 medicines are interchangeable like-for-like. They share a class, but tirzepatide (Mounjaro) activates both GIP and GLP-1 receptors, while semaglutide (Wegovy) acts on the GLP-1 receptor alone. That distinction matters clinically. It doesn't make one medicine better as a blanket rule, it makes them different, and which suits you is a question a prescriber answers with you, not one a webpage answers for you. Our Wegovy overview sets out how semaglutide works and what the UK licence covers.

Side-by-side: Wegovy against the medicines people most often switch from

The table below compares Wegovy with Mounjaro and Ozempic on the facts that matter most when you're considering a switch. One important note on Ozempic: it contains the same active ingredient as Wegovy (semaglutide), but it holds a UK licence for type 2 diabetes, not weight management. If you're taking Ozempic, your prescriber will have a specific clinical reason for it, and our guide to switching from Ozempic to Wegovy explains what that clinical transition involves. Our Wegovy vs Ozempic comparison explains the distinction in full.

For people switching from liraglutide (Saxenda), the jump to semaglutide involves a different compound with a longer half-life and a different dose ladder. Our page on switching from Saxenda to Wegovy covers how that works in practice.

What the evidence actually says about Wegovy's results in 2025–2026

Wegovy's trial record is solid. The STEP 1 trial, published in the New England Journal of Medicine, found an average body-weight reduction of around 15% over 68 weeks at the 2.4mg maintenance dose, alongside lifestyle support. The SURMOUNT-5 head-to-head trial (2025) found tirzepatide produced greater average weight reduction than semaglutide 2.4mg over 72 weeks, a result that's relevant if you're switching from Mounjaro to Wegovy and want to understand what the data says about direction of travel.

The picture shifts somewhat at the higher dose. On 14 April 2026, the MHRA approved a dedicated single-dose 7.2mg Wegovy pen, following trial data showing around 20.7% average weight loss over 72 weeks at that dose. That narrows the gap with tirzepatide considerably. The MHRA's announcement sets out the specifics. The 7.2mg pen is licensed for BMI ≥30; which dose you'd start or continue on is decided at consultation. Wegovy also now holds an approval for reducing cardiovascular event risk in eligible adults, and a conditional UK approval from July 2026 for a form of liver disease (MASH), neither of which nume prescribes for, but worth knowing if your medical history makes those relevant.

If you're moving from a different GLP-1 and wondering whether to stay with semaglutide or try a different approach, you can read more about the reasons people switch to Wegovy and what the process looks like from here.

Starting a switch: what happens at the consultation

A switch is not simply an admin task. At nume, every new prescription (including switches) is reviewed by a GPhC-registered Independent Prescriber. They look at what you're currently taking, your dose, how long you've been on it, and how you've tolerated it. For transfer patients, we ask for evidence of your current treatment before a dose is confirmed. That's not bureaucracy for its own sake; it's the only safe way to establish where you actually are in your treatment journey.

Practically: if you order before 12pm on a working day and your switch is approved as clinically suitable, your Wegovy is dispatched the same day. DPD delivers it to your door the next working day, tracked, in plain packaging. The pen needs to be kept in the fridge. If you have questions between doses, aftercare is available seven days a week. One thing our prescribers hear regularly from people making a switch: they wish they'd asked their questions earlier rather than managing uncertainty alone. The contact page is there for that.

For a broader look at what's available and how the options compare, our weight-loss treatment overview is a good starting point. Which medicine suits you is a clinical decision our prescribers make with you, not something this page, or any page, can settle on your behalf.