Mounjaro®
Starting from £179.99/mo
Start journey Learn moreWhat the evidence and clinical reality tell us about moving from Mounjaro to Wegovy
Step 1, understand why the switch feels different for most people
Mounjaro (tirzepatide) activates two receptors: GIP and GLP-1. Wegovy (semaglutide) works on GLP-1 alone. That second receptor (GIP) appears to amplify appetite suppression and metabolic effect, which is why direct comparisons between Wegovy and Mounjaro consistently show tirzepatide producing greater average weight loss. In the SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, tirzepatide produced meaningfully greater average weight reduction than semaglutide 2.4mg over 72 weeks in adults with obesity who did not have diabetes.
When you remove that second pathway by switching to Wegovy, your body is working with a single-receptor signal. For some people the transition is smooth; appetite stays suppressed and progress continues. For others, hunger returns more noticeably in the weeks after switching. Neither outcome is guaranteed, individual response varies considerably, and a prescriber reviewing your full picture is the only way to anticipate it.
One practical thing you can do in under a minute: before any switch, check the patient information leaflet for whichever medicine you are moving to. The MHRA-approved leaflet for semaglutide is listed on the electronic Medicines Compendium, and reading the side-effect section in advance helps you recognise what is expected versus what needs medical attention.
Step 2, the clinical picture that leads people to switch in the first place
There are genuine reasons a prescriber might support moving from Mounjaro to Wegovy. Mounjaro may not be tolerated at effective doses for some people: persistent nausea, injection-site reactions, or other side effects can make titration difficult. Supply considerations can also arise, though both medicines are now more reliably available than in earlier shortage periods. Occasionally, a patient's clinical profile changes in a way that makes one option more appropriate than the other.
What is less common (and worth being clear about) is switching because Mounjaro stopped working entirely. If weight loss has plateaued on tirzepatide, the more likely explanation is that the dose needs review, that lifestyle factors have shifted, or that a longer maintenance period is needed, rather than a fundamental resistance to the medicine. Comparing how Wegovy and Mounjaro work differently can help frame whether a switch is the right answer or whether another clinical adjustment makes more sense.
Semaglutide does work for many people, and if you are wondering whether Wegovy works as well as Mounjaro, the honest answer is that it produces strong results in its own right, even if tirzepatide tends to come out ahead in head-to-head data. STEP 1, published in the New England Journal of Medicine, reported around 15% average body-weight reduction over 68 weeks at the 2.4mg maintenance dose. That is a substantial result; it simply tends to sit below tirzepatide's figures in head-to-head data. A prescriber's job is to judge whether Wegovy's profile is the right fit for you specifically, not to rank medicines in the abstract.
Step 3, what the comparison table shows
The table below sets out the key factual differences. The numbers come from the respective NICE appraisals and published trial data; they describe averages across study populations, not predictions for any individual.
| Feature | Mounjaro (tirzepatide) | Wegovy (semaglutide) |
|---|---|---|
| Mechanism | Dual GIP and GLP-1 receptor agonist | GLP-1 receptor agonist |
| Average weight loss in trials | ~20–21% at 15mg over 72 weeks (SURMOUNT-1, NEJM) | ~15% at 2.4mg over 68 weeks (STEP 1, NEJM); ~20.7% at 7.2mg |
| Head-to-head (SURMOUNT-5) | Greater average reduction | Lower average reduction at 2.4mg |
| UK licensed for weight management | Yes (NICE TA1026) | Yes (NICE TA875) |
| Administration | Once-weekly injection, 6 dose strengths | Once-weekly injection; oral tablet (Wegovy Pill) also approved from June 2026 |
| NICE NHS eligibility threshold | BMI ≥35 plus ≥1 weight-related comorbidity | BMI ≥35 plus ≥1 weight-related comorbidity; specialist service required |
Sources: NICE TA1026 (tirzepatide); NICE TA875 (semaglutide); SURMOUNT-5, NEJM 2025.
Step 4, how a prescriber approaches the switch decision
No reputable prescriber will issue a new prescription for Wegovy after Mounjaro without reviewing your current status. At nume, that review covers your current dose, your response to date, your reason for wanting to switch, and any side-effect history, the same rigour applied to a first prescription, not a lighter-touch repeat. Our prescribers are GPhC-registered and each consultation is read by a person. You can read more about our clinical team on our clinical lead's profile page.
If Wegovy is clinically appropriate, the starting dose for semaglutide is 0.25mg regardless of where you were on tirzepatide. You do not carry your dose level across medicines; the titration schedule restarts to let your system adjust. That is a factual point many people are surprised by when they ask what switching to Wegovy after Mounjaro actually involves in practice, and it often leads to a broader question about whether Wegovy works the same way as Mounjaro once your body has adapted to tirzepatide.
The honest answer to the question this page started with is: yes, Wegovy can work after Mounjaro, but which medicine suits you, at what dose, for how long, is a clinical decision our prescribers make with you. Many people also ask whether Wegovy works like Mounjaro in terms of how it feels day to day, and that is exactly the kind of question worth raising during your consultation. If you would like that conversation, start your free consultation and a prescriber will review your situation the same day.
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