Wegovy and Mounjaro doses compared: what the evidence shows

What the trials recorded at each medicine's highest licensed dose

The most useful place to start is the clinical evidence, because that is what regulators used to license both medicines. In the STEP 1 trial (68 weeks, published in the New England Journal of Medicine) adults taking 2.4 mg semaglutide (Wegovy) lost an average of around 15% of their body weight alongside a reduced-calorie diet and activity programme. In SURMOUNT-1, also published in the NEJM and lasting 72 weeks, adults taking tirzepatide 15 mg (Mounjaro) lost an average of around 20–21%. The two trials were not head-to-head studies, so those figures carry different populations, different baseline weights and different protocols. A direct comparison came later: in the SURMOUNT-5 trial (2025), tirzepatide produced a greater average weight reduction than semaglutide 2.4 mg over 72 weeks in adults with obesity and without diabetes. NICE's appraisal of tirzepatide (TA1026) notes that indirect comparisons also favour tirzepatide, while acknowledging the limitations of cross-trial reading.

A newer Wegovy dose, 7.2 mg weekly, was approved by the MHRA in April 2026, and our page on how Wegovy doses compare to Mounjaro sets that development in context alongside the full trial picture. Early data put average weight loss at around 20.7% over 72 weeks at that dose — narrowing the gap with tirzepatide 15 mg considerably. That context matters when comparing the two medicines: the comparison shifts as each programme evolves.

The dose ladders side by side

The schedules differ structurally, not just numerically. Wegovy's titration is driven by tolerability across five steps; Mounjaro's six steps are also tolerability-led, with the 2.5 mg starting dose serving as a settling-in period rather than a weight-loss stage. The table below sets out the licensed UK progression for each.

Each step is typically held for around four weeks before a prescriber considers moving up. The pace is not fixed; it responds to how a person is tolerating the current dose. A fuller breakdown of how those steps sit against each other is covered in our guide to Mounjaro and Wegovy doses.

One detail that confuses a lot of people: the numbers on each medicine's scale are not comparable. If you are trying to work out how a specific Wegovy dose compares to Mounjaro, it helps to understand that 2.4 mg of semaglutide and 15 mg of tirzepatide cannot be ranked by size alone, they are different molecules, different formulations, measured differently. Our page on Wegovy vs Mounjaro doses unpacks that distinction clearly if you want more on it.

How the mechanisms account for the dose difference

This is the part that often surprises people. Mounjaro is a dual GIP and GLP-1 receptor agonist, it activates two gut-hormone receptors involved in appetite regulation and blood-sugar signalling simultaneously. Wegovy acts on GLP-1 receptors alone. That additional GIP pathway is the leading explanation for tirzepatide's stronger average results in trials, and it is why the two medicines behave differently even when dose numbers look similar on paper. The NHS patient-level pages for both tirzepatide and semaglutide describe the mechanisms in plain language if you want the clinical detail without the jargon.

Side-effect profiles overlap significantly, nausea, loose stools, constipation and indigestion feature prominently for both, particularly at dose increases. That similarity makes sense given the shared GLP-1 pathway. Neither medicine is gentler than the other in an absolute sense; individual responses vary, and what settles for one person may not settle for another. If you are currently on one and wondering about switching, that conversation belongs with a prescriber rather than a dose chart. Our page on converting between the two dose schedules is a good starting point.

Licensed eligibility and what shapes the prescribing decision

Both medicines hold UK licences for weight management in adults with a BMI of 30 or above, or a BMI of 27 or above alongside at least one weight-related condition such as high blood pressure, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea. That broad overlap means eligibility alone rarely determines which medicine is prescribed; the decision turns on the individual's health picture, any medicines they are already taking, and how they weigh up the dose schedules and evidence.

We know that can feel like an anticlimactic answer when you are trying to plan. The honest truth is that a dose comparison table can tell you what the trials found and how the schedules run, it cannot tell you which option will suit your body, your current medications or your circumstances. That is what the prescriber is there for.

NICE recommends tirzepatide under TA1026 for adults with a BMI of 35 or above plus at least one weight-related comorbidity on the NHS, with lower thresholds for some ethnic backgrounds. Semaglutide (Wegovy) has a separate NICE recommendation. Neither is freely available on the NHS without meeting those criteria. Private treatment through a regulated online pharmacy is the route most people use if they do not meet NHS thresholds or prefer not to wait. You can explore what that looks like for you through our treatment options page, or read how the two medicines compare overall at Wegovy vs Mounjaro.

Which suits you is a clinical decision our prescribers make with you, not one a dose chart can settle.