Mounjaro to Wegovy conversion: what changes and what stays the same

Picture this: you have been on Mounjaro for several months and it is working, but your supply has been interrupted

Or perhaps the reverse: you started on Wegovy, you are stable at 1.7mg, and your prescriber is considering whether tirzepatide might suit you better. Either way, the first thing to understand is that Mounjaro and Wegovy are not the same drug at different doses. Mounjaro contains tirzepatide, a dual GIP and GLP-1 receptor agonist made by Eli Lilly. Wegovy contains semaglutide, a GLP-1 receptor agonist alone, made by Novo Nordisk. The mechanisms overlap (both slow gastric emptying and reduce appetite) but the additional GIP pathway in tirzepatide means the two medicines sit on different clinical scales entirely.

That matters because there is no published, validated conversion table in the way there might be, say, for opioid analgesics. What clinicians use instead is a clinical judgement based on how far along the titration schedule you are, how well you have tolerated treatment, and what result you have achieved. Our clinical team at nume works through exactly this when a patient asks about switching. The full side-by-side profile of Wegovy versus Mounjaro covers the mechanism and evidence in more depth if you want the broader picture first.

What the dose ranges actually look like, side by side

The table below sets out the licensed UK dose steps for each medicine. Neither column maps neatly onto the other, which is precisely why a prescriber needs to be involved in any wegovy to mounjaro conversion or the other way around.

The trial evidence above is sourced from SURMOUNT-1, published in the New England Journal of Medicine, and from the NICE technology appraisal TA1026 for tirzepatide and TA875 for semaglutide. Numbers should be treated as population averages from controlled conditions, not individual predictions.

How a prescriber approaches a mounjaro conversion to wegovy — or the reverse

Because the dose ranges do not correspond numerically, the clinical starting point is not arithmetic. A prescriber will generally consider: how long you have been on treatment, which dose you reached and whether you hit it by steady titration or had to pause because of side effects, and what your weight trajectory has looked like. Someone stable at Mounjaro 10mg who switches to Wegovy will not begin at the equivalent numeric dose, the numbers mean entirely different things. The prescriber maps to a tolerable and clinically appropriate rung on the new medicine's schedule, which for most people means restarting at a lower dose and titrating again.

That is not a step backwards. It is how the medicines are designed to work. The GI side-effect profile for both medicines is similar (nausea, loose stools, indigestion and reduced appetite are common early on, easing within a couple of weeks for most people) and retitrating from a lower dose is the safest way to let your body adjust to a new molecule. For a fuller look at how the two dose ladders compare, the Wegovy to Mounjaro conversion chart page works through the titration logic in more detail. If you are weighing up the cost difference between Wegovy and Mounjaro, that is worth factoring into the conversation with your prescriber too.

Patients transferring to us from another provider are asked to provide evidence of their current treatment and dose, this is part of how our prescribers make that switch safely. Once approved, the pen is dispatched the same day and arrives via tracked DPD delivery the next working day, in plain, unbranded packaging; you can follow it on your phone.

Which medicine is right for you after a switch?

There is no universal answer, and anyone claiming otherwise is oversimplifying. The head-to-head SURMOUNT-5 trial (2025) found tirzepatide produced greater average weight loss than semaglutide 2.4mg over 72 weeks, but the 7.2mg Wegovy dose narrows that gap considerably, and individual responses vary. Weighing up Wegovy and Mounjaro more broadly (beyond the conversion question) is the right context for that discussion. If you have been on Mounjaro and your switch query is specifically about moving to Ozempic rather than Wegovy, it is worth knowing that Ozempic is licensed for type 2 diabetes, not weight management; the weight-loss route stays with Wegovy.

A common question when people research a Mounjaro and semaglutide comparison is whether the two medicines are essentially the same thing. They are not, different molecules, different receptor targets, different clinical trial programmes. What the conversion from one to the other actually looks like for you, at your current dose and medical history, is a question our prescribers can answer directly. Check your eligibility and start a free consultation, and a GPhC-registered prescriber, not software, will review your situation the same day.