Mounjaro®
Starting from £179.99/mo
Start journey Learn moreHow Saxenda and Mounjaro compare: mechanism, evidence and licensed use in the UK
You're comparing two medicines that tackle weight very differently
Imagine you've been injecting Saxenda daily for six months. You've seen some progress, but the plateau has arrived and you're wondering whether Mounjaro is genuinely a step forward or just a newer name on a similar idea. That's a fair question, and the mechanism is the first place to look.
Saxenda contains liraglutide, which activates a single gut-hormone receptor (GLP-1) to reduce appetite and slow how quickly food leaves your stomach. Mounjaro (tirzepatide) also activates the GLP-1 receptor, but adds a second one: GIP. That dual action on two separate pathways is what makes tirzepatide structurally different from any earlier weight-loss injection. There is currently no other dual GIP and GLP-1 receptor agonist licensed for weight management in the UK.
Saxenda is given daily. Mounjaro is a once-weekly injection via a pre-filled KwikPen, which many people find meaningfully easier to fit around a normal week. The titration schedules differ too, Mounjaro begins at 2.5mg to help your system adjust, with the prescriber stepping up the dose over time, typically in four-weekly increments through six available strengths up to 15mg. Saxenda's maximum dose is 3mg daily. For a full breakdown of how tirzepatide works in practice, the Mounjaro treatment page covers it in detail.
What the clinical evidence says about weight loss with each medicine
A question our prescribers hear most weeks is some version of: "Is Mounjaro actually better, or is that just marketing?" The trial data give a clear answer, though it comes with the usual caveat that averages in a clinical trial don't predict individual results.
In the SURMOUNT-1 trial (2,539 adults with obesity, 72 weeks, published in the New England Journal of Medicine) participants on tirzepatide 15mg lost around 20 to 21% of body weight on average. The SCALE trial for liraglutide 3mg (the Saxenda dose) showed average weight loss of around 8% over 56 weeks at the same lifestyle-support level. These trials used different populations and designs, so direct comparison requires care, but NICE's appraisal of tirzepatide (TA1026) acknowledged the indirect evidence favouring tirzepatide over earlier GLP-1 agents including liraglutide.
The table below sets the key facts side by side. Numbers reflect published trial data and licensed information; individual results vary.
| Feature | Saxenda (liraglutide) | Mounjaro (tirzepatide) |
|---|---|---|
| Mechanism | GLP-1 receptor agonist | Dual GIP + GLP-1 receptor agonist |
| Injection frequency | Daily | Once weekly |
| Average weight loss in trials | ~8% (SCALE, 56 weeks, 3mg) | ~20–21% (SURMOUNT-1, 72 weeks, 15mg) |
| UK weight-loss licence | Yes (BMI ≥30, or ≥27 + condition) | Yes (BMI ≥30, or ≥27 + condition) |
| NICE recommendation | Not specifically appraised for weight loss by NICE | Recommended (TA1026, December 2024) |
| Dispensed by nume for weight loss | No | Yes |
For anyone weighing up the broader GLP-1 landscape, our comparison with retatrutide looks at what's coming next in this class of medicines.
What's licensed for weight loss in the UK, and where Saxenda sits
Saxenda holds a UK marketing authorisation for weight management. It is a legitimate, licensed medicine. nume does not dispense it, and this page won't direct you toward obtaining it. What matters practically is understanding which medicines are currently available through a regulated private pharmacy, and what the NHS recommends.
NICE has published guidance recommending tirzepatide (Mounjaro) for NHS use under TA1026, for adults with a BMI of at least 35 and at least one weight-related comorbidity, with lower thresholds for some ethnic backgrounds. A separate NICE appraisal covers semaglutide (Wegovy). Liraglutide has not been through the same NICE weight-loss appraisal process, and NHS England's medicines-for-obesity commissioning does not currently include it. That doesn't make Saxenda ineffective; it reflects how the evidence and value assessments have moved since newer agents arrived.
Through nume, the two licensed weight-loss options are Mounjaro and Wegovy. If you're considering switching from Saxenda to one of them, that's a conversation worth having with a prescriber, the guide on switching from Saxenda to Mounjaro covers what that process typically involves. And if you've already started researching the switch, the detailed Saxenda vs Mounjaro page goes deeper on dose equivalence and the timing of a changeover.
How to take the next step with a medicine that IS available to you
If you've read this far, you're probably deciding whether to start Mounjaro, switch to it, or just understand what you'd be moving toward. The clinical suitability question (which medicine suits your health picture) is one a prescriber has to answer with you, not a comparison article.
nume's process starts with a free consultation, reviewed the same day by a GPhC-registered Independent Prescriber. There's photo-ID verification, live weight confirmation on video, and a Summary Care Record check where appropriate. If tirzepatide is clinically suitable, your prescription is issued and treatment dispatched the same day (orders placed before 12pm Monday to Friday). You can verify nume's pharmacy registration (GPhC number 9012878) directly on the GPhC register.
For a clear picture of what to expect from the treatment itself, real-world Mounjaro experience is worth reading alongside the trial data. And if cost is part of your thinking, the Mounjaro prices page explains what private treatment typically costs and what's included. Which medicine is right for you is a clinical decision our prescribers make with you, not one a webpage can settle.
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