What Is 0.25mg Wegovy Equivalent to in Mounjaro?

Step 1: understanding what a starting dose is actually for

Both Wegovy and Mounjaro open on a low dose that the prescribing guidelines describe as a tolerability dose. The first pen's job is to settle your system, not to treat. Nausea, bloating and loose stools are common in the first weeks, and starting low reduces how sharp those effects are.

For Wegovy, the opening step is 0.25mg weekly. For Mounjaro, it is 2.5mg weekly. Neither figure is where the clinical action mainly happens. NICE's appraisal of tirzepatide (TA1026) and the equivalent recommendation for semaglutide (TA875) both describe weight outcomes at maintenance doses, not the initial steps.

Practically: if you have been on 0.25mg Wegovy and your prescriber is considering switching you to Mounjaro, they will not simply look at a conversion table. They will assess how long you have been at your current dose, what side effects you have experienced and what your weight trajectory looks like. The dose they choose will follow from that, not from arithmetic.

Step 2: mapping both titration ladders side by side

A question our prescribers hear most weeks is some version of: "I'm on the starting Wegovy dose, what would that be on Mounjaro?" The honest answer is that no regulatory body or clinical guideline publishes a head-to-head conversion chart, because the two medicines act through different mechanisms. Wegovy activates one receptor (GLP-1); Mounjaro activates two (GLP-1 and GIP). Comparing doses between them is a bit like comparing engine sizes across different fuel types.

What we can do is show you where each sits in its own schedule.

Each step typically lasts around four weeks, though the prescriber sets the pace. For more context on how doses compare across the two schedules, our guide to Mounjaro-to-Wegovy dose conversion covers the full picture. Readers curious about the other end of the Wegovy ladder will find useful detail in the comparison of what Mounjaro dose corresponds to Wegovy 2.4mg.

Step 3: what the clinical trial evidence tells us about eventual outcomes

Because starting doses are about tolerability, results data sits at the maintenance end. In the SURMOUNT-1 trial, tirzepatide at 15mg produced an average body-weight reduction of around 20–21% over 72 weeks in adults with obesity. The STEP 1 trial found semaglutide 2.4mg averaged around 15% reduction over 68 weeks. Both trials involved adults without type 2 diabetes; both are published in the New England Journal of Medicine.

In SURMOUNT-5, a direct head-to-head over 72 weeks, tirzepatide produced greater average weight loss than semaglutide 2.4mg. The newer 7.2mg Wegovy pen, approved by the MHRA in April 2026, reported around 20.7% average loss in its pivotal trial, narrowing the gap at the top of the range.

None of that tells you which medicine is right for you. It tells you what the populations in those trials experienced on average. Individual response varies, starting at 0.25mg or 2.5mg tells you very little about where you will land at maintenance, and factors like your comorbidities, other medicines and how you tolerate GI side effects all shape the clinical decision. A broader look at how the two medicines compare overall is covered on our Wegovy vs Mounjaro comparison page.

Step 4: switching between the two medicines, what actually happens

Some people start on Wegovy and later move to Mounjaro, or vice versa. This happens because supply changes, clinical response differs from expectations, or a prescriber judges that one medicine suits a patient better at a particular stage. The starting point for a switch is not mechanical equivalence, it is a fresh clinical assessment.

Prescribers will typically consider how long you have been on your current medicine, your weight response, your side-effect profile and any relevant health changes. Transfer patients at nume provide evidence of their current treatment; dose increases require evidence too. If you are thinking about switching and wondering where you might land on the other medicine's ladder, our page on the Wegovy 1mg to Mounjaro comparison looks at a mid-titration example, and this page addresses the 7.5mg Mounjaro question specifically.

Cost is sometimes part of the decision. The two treatments sit at different price points depending on dose and provider. Our cost comparison for tirzepatide vs semaglutide sets out the landscape honestly. Which medicine suits you is not a cost question first, it is a clinical one that our prescribers work through with you.

To explore your options or discuss a switch, start a free consultation with our clinical team.