Is 5mg Mounjaro Equivalent to a Wegovy Dose?

You're on 5mg Mounjaro and wondering where that lands on the Wegovy scale

It's a question our prescribers hear regularly, usually from people who are switching between services or trying to understand what a dose change might mean. The confusion is understandable. Both medicines are once-weekly injections, both slow gastric emptying and reduce appetite, and both are titrated upward from a low starting dose. The numbers feel like they ought to correspond.

They don't, quite. Mounjaro's licensed UK doses run from 2.5mg up to 15mg across six steps. Wegovy's titration climbs from 0.25mg to a standard maintenance dose of 2.4mg, with a newer 7.2mg pen now also approved by the MHRA. The scales are structurally different because tirzepatide activates two gut-hormone receptors (GIP and GLP-1), while semaglutide targets GLP-1 alone, so the molecules themselves are not dose-equivalent in any simple sense. A 5mg Mounjaro dose is the third step in its own titration ladder; it sits above the 2.5mg starter pen and below the 7.5mg step. If you want to understand how Wegovy's strength compares to Mounjaro across the full range, that context helps explain why the two scales don't map onto each other neatly. Within Wegovy's schedule, the dose that also occupies a mid-titration position is the 1.0mg or 1.7mg weekly injection, though that comparison is contextual rather than clinical.

For a fuller look at how the two schedules map against each other across all doses, the Mounjaro-to-Wegovy dose overview walks through each step in detail. But the practical question (what to take) remains one for your prescriber, not a conversion chart.

What the trial data shows at the doses that matter most

The clearest head-to-head evidence comes from SURMOUNT-5, a 72-week open-label trial of 751 adults with obesity and no diabetes, published in the New England Journal of Medicine in 2025. Participants on tirzepatide (titrated up to 15mg) achieved greater average weight reduction than those on semaglutide 2.4mg. NICE's appraisal of tirzepatide (TA1026) notes that indirect comparisons also tend to favour tirzepatide, while acknowledging the limitations of cross-trial inference.

Earlier, the SURMOUNT-1 trial (roughly 2,500 participants) reported average body-weight reductions of around 20–21% at tirzepatide 15mg over 72 weeks. STEP 1, the pivotal semaglutide trial, reported approximately 15% average reduction at 2.4mg over 68 weeks. These are population averages from controlled trials; individual results vary considerably. The MHRA has also approved a 7.2mg Wegovy pen, with trial data reporting around 20.7% average weight loss at that dose, narrowing the gap seen at 2.4mg.

What this means at 5mg specifically is harder to state, because 5mg is a titration step rather than the doses at which long-term efficacy is usually reported. People experience meaningful effects at 5mg, but the licensed endpoint data is anchored to maximum tolerated doses. The Wegovy vs Mounjaro comparison page covers the full evidence picture, including SURMOUNT-5 in more detail.

A simple dose reference table

The table below shows where 5mg Mounjaro sits within its titration schedule alongside the comparable Wegovy titration steps. No row implies clinical equivalence, this is structural context only.

For a closer look at how the 1mg Wegovy step relates to early Mounjaro doses, the Wegovy 1mg and Mounjaro equivalent page goes into that specific crossover. And if you're thinking about costs alongside clinical fit, the Mounjaro and Wegovy price comparison sets out what private treatment typically costs at different dose stages.

Which medicine suits you, and how our prescribers work that out

Here's a misconception worth clearing up gently: many people assume the two medicines are interchangeable because they treat the same condition and share a broadly similar mechanism. They're related, but that doesn't make them substitutes at equivalent doses. A prescriber considers your weight-loss history, any conditions you're managing, your tolerance of previous doses, and practical factors like how you feel about injections versus tablets, before recommending a switch or a starting point.

Both Mounjaro and Wegovy are licensed for adults with a BMI of 30 or above, or 27 or above with a weight-related condition. Lower thresholds apply for some ethnic backgrounds under UK guidance. BMI alone doesn't determine suitability; the full picture does. You can read about our clinical team's approach on the clinical team profile page.

The dose conversion overview covers the broader question of switching between medicines, including what evidence is available to guide that decision. If you want to discuss your specific situation, the simplest step is a free consultation. Our prescribers review every submission the same day, a real clinician, not an automated system. Speak to our prescribers and start your free consultation.