Switching from Wegovy to Mounjaro: What the Dosing Change Involves

How do the two dose schedules actually differ?

Wegovy (semaglutide) follows a five-step weekly injection schedule: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg. Most people spend around four weeks at each level before their prescriber moves them up. The 2.4 mg dose is the standard maintenance target, though the MHRA approved a higher 7.2 mg maintenance dose in January 2026, with a dedicated single-dose pen following in April 2026, meaning there is now a route to greater weight loss on semaglutide than was available even recently.

Mounjaro (tirzepatide) runs a different course: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. The 2.5 mg starting dose exists specifically to let the body adjust, not to produce weight loss. Therapeutic effect builds as the dose rises over subsequent months. Tirzepatide is the only dual GIP and GLP-1 receptor agonist licensed for weight management in the UK, meaning it activates two appetite-regulating pathways rather than one. The NHS medicines page for tirzepatide gives a clear patient-level overview of how both pathways work together.

One practical check worth doing before any consultation: pull up your current Wegovy pen and note the dose you're on now. That single detail helps a prescriber immediately frame where you are in your treatment journey.

Is there a recognised equivalent dose when crossing from Wegovy to Mounjaro?

No direct conversion exists in prescribing guidelines. The two molecules differ at a structural level, and because tirzepatide acts on an additional receptor, any strength-to-strength comparison is an approximation at best. What a prescriber considers when deciding where to start you on Mounjaro includes how long you've been on semaglutide, whether you're on a maintenance dose or still titrating, your tolerability history (particularly any nausea or GI symptoms), and your current weight trajectory.

Broadly, someone who has reached and tolerated Wegovy's 2.4 mg maintenance dose may not need to restart at 2.5 mg Mounjaro, though some prescribers prefer a conservative beginning regardless. Someone who is mid-titration on semaglutide, or who experienced side effects at higher doses, is more likely to begin at the lower rungs of the tirzepatide ladder. There is no shortcut here, and any service offering a mechanical conversion without reviewing your records should raise a question in your mind.

The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, found that tirzepatide produced greater average weight reduction than semaglutide 2.4 mg over 72 weeks in adults with obesity, and our Mounjaro vs Wegovy page explores what those findings mean in practice for people weighing up the two medicines. NICE's appraisal of tirzepatide (TA1026) also notes indirect comparisons favouring tirzepatide, which is part of why some people explore making this switch.

What does the evidence say about outcomes when switching medicines?

Head-to-head switch data are limited. Most of the comparative evidence comes from separate trials rather than studies of patients who moved from one medicine to the other. That said, a few things are reasonably well established. People who have reached a plateau on semaglutide sometimes see further progress on tirzepatide, possibly because the added GIP pathway produces a different pattern of appetite signalling. Others find the tolerability profile changes, tirzepatide's GI side effects follow a broadly similar pattern to semaglutide's (nausea, constipation, reflux are common early on), but individual experience varies.

The comparison table below uses figures from the respective clinical trials. Numbers should be read as population averages, not individual predictions.

A fuller side-by-side breakdown of both medicines is on our Wegovy vs Mounjaro comparison page. For a closer look at the reverse switch (people moving from Mounjaro to Wegovy) there is a separate page covering Mounjaro to Wegovy dosing considerations.

How does a prescriber actually manage the transition at nume?

Switching between these medicines at nume is handled as a clinical transfer, not a standard new start. Our prescribers (you can read about our clinical team on the clinical team page) review your evidence of current treatment and your dose history before making any recommendation, and if you want to understand what that process looks like step by step, our guide to moving from Mounjaro to Wegovy walks through the clinical considerations in detail. Transfer patients are not assumed to need the 2.5 mg starter dose automatically, but they are also not simply issued the highest tolerated semaglutide equivalent; the prescriber looks at the whole picture.

Once a decision is reached, treatment is dispatched the same day for free next-working-day delivery if you order before 12pm. Aftercare continues throughout titration, and dose increases require a clinical re-review rather than an automatic renewal. Every step involves a prescriber reading your records. That isn't a marketing point, it's what safe titration of a prescription-only medicine requires. If you're weighing up the cost side of a switch, the cost difference between Mounjaro and Wegovy is covered separately. Which medicine is clinically right for you is a decision our prescribers make with you, based on your full history, not a table.