1mg Wegovy Compared to Mounjaro: What the Dose Difference Actually Means

Why can't you compare 1mg Wegovy and Mounjaro dose-for-dose?

The number on the pen describes the mass of the active molecule. Semaglutide and tirzepatide are different molecules with different molecular weights, different receptor targets and different titration ranges, so 1mg of one has no equivalent value in the other's schedule.

Wegovy's licensed titration runs 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg, with 1mg sitting as the third rung in the escalation sequence. Mounjaro's range spans 2.5mg through to 15mg in six steps. The numeric gap is a quirk of chemistry, not a reflection of potency. You can read more about how the full Wegovy titration maps across in the Wegovy doses compared to Mounjaro overview, which covers the whole ladder rather than a single point on it.

At 1mg, a patient on Wegovy is still in the early phase of dose escalation, the body is adapting, and the maintenance dose of 2.4mg (or the newer 7.2mg for those who qualify) is still ahead. Meanwhile, a Mounjaro patient starting on 2.5mg is also in an adjustment phase, with the higher therapeutic doses of 10mg or 15mg further down the road. Comparing the two at these early doses is a bit like comparing two runners at different points in a race and calling it a finish-line result.

The Wegovy dose compared to Mounjaro page explores the broader context of how clinicians think about these schedules side by side.

What does the clinical evidence say about each medicine's weight-loss results?

The most reliable comparison comes from the SURMOUNT-5 trial, an open-label head-to-head study published in the New England Journal of Medicine in 2025, which compared tirzepatide directly against semaglutide 2.4mg in 751 adults with obesity and no diabetes over 72 weeks. Tirzepatide produced a greater average percentage body-weight reduction. NICE's technology appraisal of tirzepatide (TA1026) also notes that indirect comparisons favour tirzepatide over semaglutide 2.4mg. That said, neither trial tested the question of 1mg Wegovy specifically, the comparison is always at maintenance doses.

For Wegovy's own figures, the STEP 1 trial (68 weeks, semaglutide 2.4mg) showed an average weight reduction of around 15%, while Wegovy 2.4mg compared to Mounjaro covers those results in more detail. For Mounjaro, SURMOUNT-1 (72 weeks, tirzepatide 15mg) showed average reductions of around 20–21%, as reported in the SURMOUNT-1 paper in the New England Journal of Medicine. Neither result applies to a patient sitting at 1mg semaglutide, that is an in-progress, not a final, dose.

Both medicines carry a Black Triangle (▼) designation, meaning they are subject to additional MHRA monitoring. The NICE appraisal of tirzepatide (TA1026) and the equivalent appraisal for semaglutide (TA875) set out the evidence base in full.

Do the side-effect profiles differ between the two?

Both medicines share a similar pattern of gastrointestinal effects, nausea, loose stools, constipation and indigestion are the most commonly reported, and they tend to be most noticeable in the early weeks or after a dose step. For most people they ease off as the body settles. Neither medicine has a clearly cleaner profile than the other in this respect; individual tolerance varies considerably, and that's partly why the titration exists.

The NHS medicines page for tirzepatide covers the full side-effect list for Mounjaro, as does the equivalent page for semaglutide. For anything that concerns you after starting treatment, the Patient Information Leaflet inside your pen box is the authoritative reference, and our prescribers are available for aftercare seven days a week.

One practical point worth knowing: women using oral contraceptives who switch to or start tirzepatide should add a barrier method for the first four weeks of treatment and for four weeks after each dose increase, because tirzepatide may affect pill absorption. The NHS England guidance on weight management injections covers this, along with advice about HRT and surgery.

If you're looking at 0.5mg Wegovy compared to Mounjaro, the side-effect context is similar to 1mg, early titration for both medicines, GI effects most likely here.

Which one is right for you, and how does the consultation work at nume?

The honest answer is that neither of us can settle that question in a web page. Which medicine suits you depends on your medical history, current medications, BMI, any weight-related conditions and how you respond to treatment over time. That is a clinical call, made with a prescriber who has read your full consultation.

At nume, that prescriber is a GPhC-registered Independent Prescriber who reviews every consultation personally. If you're approved, treatment is dispatched the same day for orders in before 12pm, your pen arrives the next working day via DPD, tracked to your door in a plain box with nothing on the outside to identify the contents. No branding, no embarrassment. The Mounjaro to Wegovy dose conversion guide is worth reading if you're already on one medicine and considering switching; and if cost is part of the picture, how much Wegovy costs compared to Mounjaro lays out what the price difference looks like in practice.

For a broader view of the two medicines before you consult, the Wegovy vs Mounjaro comparison covers the full picture. And when you're ready, you can speak to our prescribers through a free consultation, no waiting list, no GP referral needed.