Mounjaro®
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Start journey Learn moreWhat the evidence actually says about GLP-1 medicines and semaglutide's place among them
The misconception: 'GLP-1' and 'semaglutide' are two different drugs
They're not. GLP-1 stands for glucagon-like peptide-1 receptor agonist — a pharmacological class that includes several distinct medicines, each sharing the same core mechanism but differing in molecule, dosing and licensed indication. Semaglutide is one drug within that class, alongside liraglutide, dulaglutide and others. Tirzepatide, which activates both the GLP-1 receptor and the GIP receptor, is sometimes grouped loosely under the GLP-1 umbrella in press coverage, though it is technically a dual agonist. Conflating the class with a single member is like saying 'statin' and 'atorvastatin' are the same thing. The distinction matters because different GLP-1 medicines carry different licences, different trial evidence and different practical profiles. If you've read that 'GLP-1 injections cause nausea' or 'GLP-1 works by slowing digestion', those statements describe the class; whether they apply to a specific medicine depends on which one is being prescribed. The mechanism comparison between liraglutide and semaglutide illustrates just how much two GLP-1 drugs can diverge at a molecular level, even when their broad action looks similar on the surface.
Semaglutide for weight loss: what's actually licensed in the UK
In the UK, the only semaglutide product licensed specifically for weight management is Wegovy, made by Novo Nordisk. The injection version has been available here since 2023. On 11 June 2026, the MHRA also approved an oral semaglutide tablet under the Wegovy brand, the first oral GLP-1 medicine licensed for weight loss in the UK. A separate product, Ozempic, also contains semaglutide but is licensed for type 2 diabetes; it is not licensed for weight management and should not be sought out for that purpose. This distinction is explained in more detail on our semaglutide vs Ozempic page. The STEP 1 clinical trial, published in the New England Journal of Medicine, reported an average body-weight reduction of around 15% over 68 weeks at the 2.4mg weekly maintenance dose. A higher 7.2mg dose was approved by the MHRA in early 2026; trials at that dose reported around 20.7% average weight loss over 72 weeks, narrowing the gap with tirzepatide. Your pen sits in the fridge door between doses, no complex storage, but the exact room-temperature window if you travel is specified in the Patient Information Leaflet rather than here.
GLP-1 medicines compared: a factual overview
The table below covers the GLP-1 medicines most commonly encountered in UK weight-management conversations. Tirzepatide is included because it activates the GLP-1 receptor (alongside GIP), so it appears in searches on this topic, but it is a distinct class. NICE's appraisal of tirzepatide (TA1026) and its appraisal of semaglutide (TA875) both inform NHS eligibility and form the clinical backdrop here.
| Medicine | Brand (UK) | Class | UK weight-loss licence | Trial weight loss (approx.) |
|---|---|---|---|---|
| Semaglutide | Wegovy (injection or tablet) | GLP-1 agonist | Yes (adults, BMI ≥30 or ≥27 with a weight-related condition | ~15% (2.4mg injection, STEP 1); ~20.7% (7.2mg injection) |
| Tirzepatide | Mounjaro | Dual GIP/GLP-1 agonist | Yes) same BMI thresholds as above | ~20–21% at 15mg (SURMOUNT-1, NEJM) |
| Liraglutide | Saxenda | GLP-1 agonist | Yes (daily injection; nume does not dispense it | ~8% (SCALE, vs placebo) |
| Semaglutide | Ozempic | GLP-1 agonist | No) licensed for type 2 diabetes only | Not applicable for weight management |
| Dulaglutide | Trulicity | GLP-1 agonist | No, licensed for type 2 diabetes only | Not applicable for weight management |
For a detailed look at how liraglutide and semaglutide compare as molecules, the liraglutide vs semaglutide page goes further. If you're weighing up semaglutide against Wegovy as brand versus medicine name, our semaglutide vs Wegovy page addresses that directly.
Which GLP-1 medicine suits you? That's a clinical question
No comparison table can answer that. Eligibility, medical history, current medicines, lifestyle and preferences all shape what a prescriber recommends. The weight-loss treatment overview covers how both Wegovy and Mounjaro fit into private treatment, and our Wegovy price comparison page puts the cost context in plain terms. For those weighing up the two weight-loss options head to head, the Wegovy vs GLP-1 medicines page adds further detail. A question our prescribers hear regularly is whether switching from one GLP-1 to another is straightforward, it depends on dosing history, tolerability and other factors that a clinical review resolves. At nume, a named prescriber reads every consultation personally. Which medicine suits you is exactly the kind of decision our prescribers make with you, based on your full picture. Speak to our prescribers through a free consultation to find out where you stand.
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