Mounjaro®
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Start journey Learn moreHow Wegovy 1.7mg and comparable Mounjaro doses perform: trial data, mechanism and what matters for switching
What the trial data tells us, and what it cannot
Comparing Wegovy 1.7mg to any Mounjaro dose is harder than it looks on paper. The STEP 1 trial, published in the New England Journal of Medicine, studied semaglutide at its 2.4mg maintenance dose over 68 weeks and found an average weight reduction of around 15% in adults without diabetes. No large trial has published granular results specifically at the 1.7mg stage, because 1.7mg is a transitional step on the way to 2.4mg rather than a sustained maintenance dose. Wegovy's titration runs 0.25mg, 0.5mg, 1.0mg, 1.7mg, then 2.4mg, with roughly four weeks at each level.
Mounjaro's titration is steeper: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg. SURMOUNT-1, which enrolled 2,539 adults with obesity, showed average weight reductions of around 20–21% at the 15mg maintenance dose over 72 weeks. NICE's appraisal of tirzepatide (TA1026) considered these figures alongside indirect comparisons with semaglutide and concluded tirzepatide produced greater average weight loss. What neither trial measures is a mid-titration crossover point, the 1.7mg versus 10mg comparison is a clinical heuristic, not a trial finding.
The head-to-head SURMOUNT-5 trial (NEJM, 2025) compared tirzepatide directly against semaglutide 2.4mg over 72 weeks in 751 adults with obesity and no diabetes. Tirzepatide produced greater average weight reduction. That result holds at the respective maintenance doses; it does not tell us what happens at 1.7mg semaglutide specifically.
Mechanism gap: why one receptor versus two changes the comparison
Wegovy contains semaglutide, a GLP-1 receptor agonist. It binds to one gut-hormone receptor, slowing gastric emptying, reducing appetite and improving blood-sugar regulation. Mounjaro contains tirzepatide, the only dual GIP and GLP-1 receptor agonist licensed for weight management in the UK. Activating both receptors appears to produce a stronger appetite-suppression signal, which is the leading explanation for tirzepatide's larger average weight-loss results in trials.
Because of this receptor difference, dose numbers are not interchangeable. A patient on Wegovy 1.7mg has reached 71% of the standard 2.4mg maintenance dose. The closest Mounjaro step by proportion is 10mg, 67% of the 15mg maintenance dose. Some clinicians use this proportional framing when advising patients who are switching between the two medicines, and you can see how other dose steps map across on the Mounjaro equivalent dose to Wegovy guide. If you are curious whether Mounjaro 5mg has an equivalent position on the Wegovy scale, that earlier step in the titration is covered in detail too.
Tolerability also differs. GI effects (nausea, loose stools, reflux) are common to both, but their timing and intensity can vary person to person. Where someone lands on one titration ladder does not predict where they will land on the other. Switching is always a prescriber decision, not a formula.
Side-by-side: Wegovy 1.7mg and Mounjaro 10mg at a glance
The table below sets out factual, comparable data points for these two doses. It is a reference, not a recommendation.
| Feature | Wegovy 1.7mg (semaglutide) | Mounjaro 10mg (tirzepatide) |
|---|---|---|
| Receptor mechanism | GLP-1 agonist (single pathway) | Dual GIP and GLP-1 agonist |
| Position in titration | Step 4 of 5; penultimate before 2.4mg maintenance | Step 4 of 6; one step below 12.5mg |
| Dosing frequency | Once weekly, subcutaneous injection | Once weekly, subcutaneous injection |
| NICE recommendation status | TA875 (semaglutide, max 2 years, specialist services) (NICE TA875 | TA1026 (tirzepatide, BMI ≥35 + comorbidity threshold)) NICE TA1026 |
| Common side effects | Nausea, diarrhoea, constipation, vomiting (GI-led; typically settle with time) | Nausea, diarrhoea, constipation, vomiting (GI-led; typically settle with time) |
| UK licence holder | Novo Nordisk | Eli Lilly |
For more on how the full dose ladders compare, the Wegovy and Mounjaro dose comparison page covers every step in both schedules. If you are specifically looking at the step before this one, the Wegovy 1mg equivalent to Mounjaro guide may also be useful.
What this means if you are considering switching or starting treatment
If you are currently on Wegovy 1.7mg and wondering what the Mounjaro equivalent would be, a prescriber will look at far more than dose position. How well you have tolerated the semaglutide titration, how much weight you have lost so far, any other medicines you take, and your medical history all shape the starting point on a new schedule. Oral contraceptive users switching to tirzepatide should be aware that NHS England's guidance advises adding a non-oral contraceptive method for the first four weeks of treatment and for four weeks after each dose increase, because tirzepatide may reduce pill absorption. No equivalent caution exists for semaglutide.
A quick habit worth building before any consultation: check your current pen's dose label and note exactly which step you are on. It takes under a minute and gives your prescriber the precise starting point rather than an approximate one. You can read more about switching between Mounjaro and Wegovy and what the conversion process involves in practice.
The cost difference between the two medicines is worth discussing too. Private prices vary by dose and provider; the Wegovy versus Mounjaro cost comparison sets out the market context clearly. At nume, one price covers the consultation with a named prescriber, the prescription itself, treatment and aftercare, explore the full picture on our weight-loss treatments page. Which medicine is the right fit is a clinical decision our prescribers make with you, not a number on a comparison table.
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