Mounjaro®
Starting from £179.99/mo
Start journey Learn moreHow Wegovy 0.5mg and early Mounjaro doses sit in their respective schedules, and where the comparison breaks down
Step 1, place each dose inside its own titration ladder
To understand what 0.5mg Wegovy is equivalent to in Mounjaro, it helps to see both schedules side by side before drawing any comparison.
Wegovy's licensed UK escalation runs: 0.25mg (weeks 1–4) → 0.5mg (weeks 5–8) → 1.0mg (weeks 9–12) → 1.7mg (weeks 13–16) → 2.4mg maintenance, with the newer 7.2mg maximum dose available for those who need further progression. The 0.5mg step is purely a tolerability bridge, your body is still adjusting, and this dose is not considered maintenance.
Mounjaro's UK schedule starts at 2.5mg for the first four weeks, then moves to 5mg, 7.5mg, 10mg, 12.5mg and finally 15mg, each step held for roughly four weeks before a prescriber reviews progression. The 2.5mg pen is a tolerability dose in exactly the same sense as Wegovy's 0.25mg and 0.5mg steps, it exists to settle the system, not to deliver the full therapeutic effect. You can read more about how Mounjaro's 2.5mg starting dose compares to Wegovy if you are earlier in the decision.
In terms of position in a titration sequence, Wegovy 0.5mg and Mounjaro 5mg both occupy the second prescribed step of their respective ladders. That is the closest positional parallel available. The mechanisms, molecular targets and dose units, however, are entirely different things.
| Wegovy (semaglutide) | Mounjaro (tirzepatide) | |
|---|---|---|
| Mechanism | GLP-1 receptor agonist | Dual GIP and GLP-1 receptor agonist |
| Second titration step | 0.5mg (weeks 5–8) | 5mg (weeks 5–8, approx.) |
| Maintenance dose | 2.4mg (up to 7.2mg) | Up to 15mg |
| Average weight loss at maintenance (clinical trials) | ~15% at 2.4mg [STEP 1, NEJM] | ~20–21% at 15mg [SURMOUNT-1, NEJM] |
| UK licence (weight management | Yes (BMI ≥30 or ≥27 with a weight-related condition) | Yes (BMI ≥30 or ≥27 with a weight-related condition) |
Step 2) why a dose number alone does not translate across these two medicines
A lot of patients switching between Wegovy and Mounjaro, or weighing up which to start, look for a conversion table. It is a completely understandable instinct. The frustrating answer is that no validated clinical equivalence exists between specific doses of semaglutide and tirzepatide.
The reason is structural. Wegovy acts on one receptor; Mounjaro activates two (GIP and GLP-1) and the combined effect on appetite, gastric emptying and metabolic signalling is not simply the sum of its parts. Comparing 0.5mg of one to 5mg of the other by milligram count is a bit like comparing the strength of two different pain relievers by their tablet size.
Clinical trials did eventually test them directly. In the SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, adults with obesity who received tirzepatide lost more body weight on average than those on semaglutide 2.4mg over 72 weeks. That head-to-head result guides prescribers but does not produce a dose conversion. You can explore how Mounjaro 5mg sits alongside Wegovy doses for more context on the early-treatment comparison, or review the full dose conversion guide for a broader look at both schedules.
What matters clinically is not which step you are on, but whether your prescriber is titrating at the right pace for your response and tolerability. The Wegovy vs Mounjaro comparison page covers the evidence behind both in more depth.
Step 3, what this means if you are considering switching or starting
If you are currently taking Wegovy 0.5mg and wondering whether to switch to Mounjaro, or if you are new to treatment and comparing early doses, the practical point is this: the conversation belongs with a prescriber, not a dose chart.
Switching mid-treatment is not as simple as finding the nearest number. A prescriber will consider how long you have been on your current step, your tolerability history, your weight response so far, and any relevant health conditions. They will not simply match dose positions. NHS England's guidance on weight management injections is clear that titration decisions sit with the clinical team managing your treatment.
For those earlier in the process (comparing 0.5mg Wegovy to alternative Mounjaro doses) the full side-by-side dose comparison and the Wegovy 1mg equivalent guide may help frame the wider picture. Cost is sometimes part of this decision too; the Wegovy vs Mounjaro cost comparison sets out what the price difference looks like in practice.
Which medicine suits you is a clinical decision our prescribers make with you. If you would like to talk through your options, speak to our prescribers through a free consultation, reviewed the same day, with no waiting list.
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