Thinking About a Swap from Mounjaro to Wegovy?

Why would someone want to swap from Mounjaro to Wegovy in the first place?

It is more common than people expect. Side effects are the most frequent driver: Mounjaro acts on two receptors (GIP and GLP-1), and a small number of patients find the dual mechanism produces GI symptoms (nausea, reflux, loose stools) that never quite settle even across several dose increases. Some of those same patients tolerate Wegovy, a single GLP-1 receptor agonist, more comfortably, and you can read more about the specific benefits Wegovy may offer over Mounjaro for people in exactly that position. The reverse also happens: people who have been on Wegovy for a year or more and feel their progress has plateaued sometimes ask whether tirzepatide's dual action might shift things again.

Occasionally the reason is purely logistical. Supply of either medicine has been stretched at points, and a prescriber may recommend a temporary or permanent switch to maintain continuity of treatment rather than stopping entirely, which carries its own risks. Personal preference (an injection pen that feels easier to use, or a different titration schedule) is a less common but legitimate factor too.

Whatever the reason, moving between these two medicines is a clinical decision, not a consumer one. A prescriber needs to understand why you want to switch, what you have tolerated so far, and what dose equivalent makes sense, the scales for the two medicines are not interchangeable and there is no single universal conversion chart.

How do Mounjaro and Wegovy actually compare on the numbers?

The evidence is clearer than it used to be. The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, put tirzepatide (Mounjaro) and semaglutide 2.4mg (Wegovy) head-to-head in 751 adults with obesity over 72 weeks. Tirzepatide produced greater average weight reduction. NICE's appraisal of tirzepatide (TA1026) also notes that indirect comparisons favour tirzepatide over semaglutide at standard doses.

That said, the gap narrows with Wegovy's newer 7.2mg dose, approved by the MHRA on 14 April 2026, which returned approximately 20.7% average weight loss over 72 weeks in trials, approaching tirzepatide's 15mg results. The table below summarises the key clinical differences.

Source: NICE TA1026; SURMOUNT-1, NEJM; MHRA approval announcement, 14 April 2026. Both medicines carry a Black Triangle (▼) indicating additional MHRA monitoring.

Can you swap from Wegovy to Mounjaro on your own, or does it need a prescriber?

A prescriber has to be involved. This is not a formality, there are real clinical reasons for it. The dose ladders run on different scales: Wegovy starts at 0.25mg and the maintenance dose is 2.4mg (or higher with the newer pen); Mounjaro starts at 2.5mg. Those figures sound similar but the medicines and their mechanisms are different enough that assuming equivalence is unsafe. When you swap between Wegovy and Mounjaro, a prescriber typically re-starts you at the lowest dose of the new medicine rather than matching where you left off, though the right approach depends on your individual clinical picture.

If you are thinking about switching because of side effects, your prescriber also needs to know: some GI symptoms are common to both medicines, and switching will not necessarily resolve them. If the issue is something like inadequate weight loss rather than tolerability, there may be factors worth addressing before changing medicine at all.

You can explore more about the specific process of making this switch (including what a prescriber typically assesses) in our dedicated guide. For a fuller side-by-side of the two medicines beyond just the switch, our Wegovy vs Mounjaro comparison covers the evidence in depth.

What should you do if you want to switch at nume?

If you are already on treatment with us, contact our team directly through our support page and a prescriber will review your case, including your current dose, the reason you want to switch, and what the right starting point on the new medicine would be for you. We do not auto-renew or auto-switch; every repeat is individually reviewed.

If you are moving to nume from another provider and want to continue on a different medicine, your consultation with us covers that transition. We ask for evidence of your current treatment and recent weight at the point of any dose change or switch request, the same clinical standard we apply to all patients. There is a cost context worth acknowledging too: the price difference between Mounjaro and Wegovy varies by dose and is worth understanding before you decide.

For many people reading this, the honest feeling is frustration: you have been on one medicine for months, something isn't quite right, and you just want someone to take the question seriously. Our prescribers do. Start your free consultation and they will work through the options with you. Which medicine suits you is a clinical decision our prescribers make with you, not for you.