Mounjaro®
Starting from £179.99/mo
Start journey Learn moreHow these two doses compare: mechanism, titration context, and the numbers that matter
Step 1, Understand what each medicine actually is
Wegovy contains semaglutide, a GLP-1 receptor agonist made by Novo Nordisk. It acts on a single gut-hormone pathway to reduce appetite and slow gastric emptying. The UK titration schedule runs from 0.25mg, up through 0.5mg, 1.0mg and 1.7mg, to a 2.4mg maintenance dose, and, following MHRA approval in January 2026, a 7.2mg maintenance option is now available for adults with a BMI of 30 or above. The 0.5mg dose sits early in that ladder: it is not a maintenance dose, it is a stepping stone.
Mounjaro contains tirzepatide, made by Eli Lilly. It is a dual GIP and GLP-1 receptor agonist, the only medicine in UK weight management to activate both pathways simultaneously. The UK titration runs from 2.5mg through 5, 7.5, 10 and 12.5mg, to a 15mg maximum. The 5mg dose is the second rung on that scale, reached after a month at 2.5mg. Like 0.5mg Wegovy, it is not where most people stay long-term.
So the short version: 0.5mg Wegovy is a mid-step on a semaglutide schedule; 5mg Mounjaro is an early step on a tirzepatide schedule. Different molecules, different mechanisms, different scales entirely. The full Wegovy vs Mounjaro comparison covers how both medicines are assessed against each other at maintenance doses.
Step 2 (See how the numbers stack up side by side
A direct clinical comparison at these specific doses does not exist in published trial data) trials measure outcomes at maintenance doses over many months, not at intermediate titration points. The table below reflects approved factual context from UK sources, not a claim that one is superior to the other at these early doses.
| Feature | 0.5mg Wegovy (semaglutide) | 5mg Mounjaro (tirzepatide) |
|---|---|---|
| Drug class | GLP-1 receptor agonist | Dual GIP and GLP-1 receptor agonist |
| Manufacturer | Novo Nordisk | Eli Lilly |
| Role in titration | Titration step (not maintenance) | Titration step (not maintenance) |
| Standard maintenance dose | 2.4mg weekly (7.2mg also approved) | Up to 15mg weekly |
| Average weight loss at maintenance (trial data) | ~15% over 68 weeks at 2.4mg [STEP 1, NEJM] / ~20.7% at 7.2mg | ~20–21% over 72 weeks at 15mg [SURMOUNT-1, NEJM] |
| UK weight-loss licence | BMI ≥30, or ≥27 with a weight-related condition | BMI ≥30, or ≥27 with a weight-related condition |
Both sets of trial figures come from thousands of adult participants across their respective phase-3 programmes. The dose-conversion guide explains in more detail why there is no clean numerical equivalence between the two schedules.
Step 3, Consider what this means if you are thinking about switching
People sometimes arrive at this comparison because they are already on one medicine and wondering whether the other is equivalent. It is a fair question. The honest answer is that there is no published conversion table that says "0.5mg Wegovy equals Xmg Mounjaro", and a prescriber would not treat it that way even if one existed. They would look at your current dose in the context of your tolerability, your response so far, your medical history and your goals.
The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, is the closest we have to a head-to-head: tirzepatide produced greater average weight reduction than semaglutide 2.4mg over 72 weeks in adults with obesity. But that comparison was at maintenance doses, not the early titration steps this page is about. If you are considering moving from Wegovy to Mounjaro, the guide on switching from 0.5mg Wegovy to Mounjaro covers the practicalities. For anyone weighing the earlier Wegovy step against Mounjaro's starter, this page on 0.25mg Wegovy versus 2.5mg Mounjaro may be more relevant.
Switching between these medicines is not simply a matter of stopping one pen and starting the other. A prescriber reviews your history, checks current evidence, and decides what dose to start you on. If you want to understand how these two specific doses compare in more detail, our page on whether 0.5mg Wegovy is the same as 5mg Mounjaro walks through the question directly. The clinical team at nume handle exactly these questions in consultations.
Step 4, Check eligibility before anything else
Both medicines share the same UK-licensed eligibility criteria: adults with a BMI of 30 or above, or 27 and above if there is at least one weight-related condition such as high blood pressure, type 2 diabetes, high cholesterol or obstructive sleep apnoea. Lower BMI thresholds may apply for some ethnic backgrounds under UK clinical guidance. A BMI figure alone never confirms suitability. Our treatment overview explains what the clinical assessment looks at beyond the number on the scale.
These are prescription-only medicines. The NHS has phased eligibility criteria that are stricter than the licensed thresholds, useful context if you are exploring whether the NHS route applies to you. Private treatment through a regulated online pharmacy is the alternative for people who do not meet current NHS criteria or prefer not to wait. Any pharmacy you consider should be listed on the GPhC register. Which medicine suits you (Wegovy, Mounjaro, or neither right now) is a clinical decision our prescribers make with you, and if you are specifically weighing up the 1mg Wegovy step against Mounjaro, our guide on whether 1mg Wegovy is the same as 7.5mg Mounjaro covers that comparison in full.
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