Wegovy Strength vs Mounjaro: How the Two Dose Ladders Stack Up

Step 1, Map out the two titration schedules

Mounjaro (tirzepatide, made by Eli Lilly) is available in six UK strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Treatment opens at 2.5 mg, a dose whose job is largely to settle the digestive system before any meaningful therapeutic effect takes hold. From there, the prescriber typically advances in 4-week steps, with 15 mg as the ceiling. Six pens, one per month, spread across roughly six months of titration.

Wegovy (semaglutide, made by Novo Nordisk) climbs a different ladder: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg, with the same approximate 4-week interval between steps. That 2.4 mg maintenance figure is the standard endpoint most patients on Wegovy reach. A higher 7.2 mg dose was approved by the MHRA on 14 April 2026 for a dedicated single-dose pen, for adults with a BMI of 30 or above, meaning there is now a sixth rung on the Wegovy ladder too, though the titration still begins at 0.25 mg and the higher dose is subject to clinical suitability.

The milligram numbers look very different on paper. That is not because one medicine is a larger molecule or a stronger compound in any simple sense, they act on overlapping but distinct receptor pathways, and the numbers reflect each manufacturer's pharmacological formulation rather than a shared scale. Comparing 15 mg of tirzepatide with 2.4 mg of semaglutide is not like comparing 15 mg of ibuprofen with 2.4 mg; the figures are not interchangeable. You can explore the dose comparison between Wegovy and Mounjaro in more detail, but the short answer is: the numbers are not on the same scale.

Step 2, Compare the clinical trial results at maximum dose

The fairest way to compare these two medicines is to look at what the published trial evidence says about weight loss at each drug's highest tested dose.

In the SURMOUNT-1 trial (2,539 adults with obesity or overweight plus a weight-related condition, 72 weeks), participants taking tirzepatide 15 mg lost an average of around 20–21% of their body weight. The SURMOUNT-1 results, published in the New England Journal of Medicine, were the basis for NICE's appraisal of tirzepatide.

The STEP 1 trial of semaglutide 2.4 mg (68 weeks) showed an average weight reduction of around 15%. Head-to-head data also exists: in the SURMOUNT-5 trial (72 weeks, 751 adults, published in NEJM 2025), tirzepatide produced greater average weight loss than semaglutide 2.4 mg in a direct comparison. The newer 7.2 mg Wegovy dose narrows that gap, published data suggest around 20.7% average weight loss over 72 weeks at 7.2 mg, approaching tirzepatide 15 mg results. NICE's appraisal of tirzepatide (TA1026) notes that indirect comparisons favour tirzepatide, while acknowledging uncertainty.

The table below sets out the key facts side by side. For a fuller breakdown of how these figures translate to real-world prescribing, the Wegovy vs Mounjaro overview covers the wider picture including mechanism and eligibility.

Step 3, Understand what drives the prescriber's choice

Looking at the mounjaro vs wegovy strength comparison purely through the lens of milligrams misses the clinical picture. The relevant questions are not which number is bigger, but which medicine a patient's history, other medications, and comorbidities point toward.

Both medicines share a broadly similar side-effect profile, nausea, loose stools, constipation, indigestion, and fatigue are the most commonly reported, typically most noticeable during the first few weeks at a new dose. Neither is right for people who are pregnant, breastfeeding, or actively trying to conceive. Women taking oral contraceptives starting Mounjaro should add a non-oral method of contraception for the first four weeks of treatment and for four weeks after each dose increase, because gastrointestinal slowing can reduce pill absorption; the same precaution does not have equivalent evidence behind it for semaglutide. NHS England's guidance on weight-management injections covers the contraception and HRT considerations in detail.

Tirzepatide is the only dual-agonist licensed for weight management in the UK, it works on two gut-hormone pathways rather than one, which is thought to account for the steeper average weight loss seen in trials. Whether that matters for a particular patient depends on their starting point, any coexisting type 2 diabetes, and tolerability. Wegovy now offers its own high-dose option at 7.2 mg, which is meaningfully different from what was available two years ago.

A good starting point if you are still weighing up the options is the detailed strength comparison between Wegovy and Mounjaro, or (if you are thinking about switching between treatments) the Mounjaro-to-Wegovy dose conversion guide explains what a clinical transition looks like, and if you are considering the reverse move, our switching from Wegovy to Zepbound dosage chart walks through how those dose steps align. Cost is a factor for many people too; the UK price comparison for Mounjaro and Wegovy sets out market context honestly.

Which of these suits you is a clinical decision our prescribers make with you, not something a dose ladder or a table can settle on its own. That starts with a free consultation at nume's treatment page.