Saxenda, Wegovy and Mounjaro Compared: What the Evidence Actually Shows

You've been looking at three names, and you're not sure which conversation to start

It's a common place to land. You've seen Saxenda mentioned in older articles, Wegovy in the news, Mounjaro appearing everywhere more recently. Each has a different dosing pen, a different injection schedule, and a different trial history behind it. Before anything else, one point is worth flagging clearly: Saxenda is no longer dispensed by nume for weight management. It is licensed in the UK for weight loss, but nume prescribes Wegovy and Mounjaro. This page compares all three fairly so you can walk into a consultation with the right questions, then our prescribers work through which option makes clinical sense for you specifically.

Saxenda contains liraglutide, made by Novo Nordisk. It is a GLP-1 receptor agonist injected once daily, titrated from 0.6mg up to 3mg over several weeks. It was the first GLP-1 injection to receive UK licensing for weight management, and for many years it was the only option. Average weight loss in its pivotal trial was around 8% of body weight. That figure is lower than what later medicines produced, which is partly why prescribing patterns have shifted. You can read more about the science underpinning GLP-1 medicines on the weight-loss treatment overview page.

A practical checking habit worth building if you are researching any injectable medicine online: look up the pharmacy selling it on the GPhC register at pharmacyregulation.org/registers. It takes under a minute and tells you whether the pharmacy is legitimately registered to dispense prescription medicines in the UK.

How the numbers compare across all three medicines

The table below draws on published trial data and MHRA-approved UK licensing. Bear in mind that trials enrol people under controlled conditions; real-world results vary, and no medicine produces the same outcome for every person.

Wegovy's recently approved 7.2mg dose narrows the gap with Mounjaro considerably. The MHRA approved a dedicated single-dose 7.2mg pen on 14 April 2026, and trials at that dose reported around 20.7% average weight loss over 72 weeks. If you are still weighing up whether Wegovy or Mounjaro is the better fit for your situation, that page works through the key differences to help you decide. For a detailed look at how the two leading options compare head to head, the Wegovy vs Mounjaro breakdown covers the trial evidence thoroughly.

Mounjaro's edge in average weight loss comes partly from its dual mechanism: it is the only weight-loss injection licensed in the UK that activates both GIP and GLP-1 receptors, which together regulate appetite and blood-sugar control through two distinct pathways. Wegovy and Saxenda act only on the GLP-1 receptor. Whether that dual action translates into a meaningfully better outcome for you depends on factors a prescriber assesses, not a headline figure.

Which patients each medicine is licensed for, and what NICE says

All three share broadly similar eligibility thresholds in their UK licences: adults with a BMI of 30 or above, or 27 or above when a weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes or obstructive sleep apnoea is present. Lower BMI thresholds apply for certain ethnic backgrounds under UK guidance.

NICE has appraised both Wegovy and Mounjaro for NHS use. Tirzepatide (Mounjaro) is recommended under NICE TA1026 for adults with a BMI of 35 or above and at least one weight-related comorbidity. Semaglutide (Wegovy) is recommended under NICE TA875 only within a specialist weight management service and for a maximum of two years. Saxenda does not have an equivalent NICE technology appraisal for weight management, which is one reason NHS prescribing has largely moved toward semaglutide and tirzepatide.

Privately, the landscape is different. A GPhC-registered prescriber can assess Wegovy or Mounjaro without a specialist referral or an NHS waiting list. The consultation page explains what that process involves at nume. For a side-by-side look at how the dosing schedules differ between Wegovy and Mounjaro, the dosing comparison page covers each titration step in detail.

Side effects, tolerability and what to expect across the three medicines

The side-effect profile across all three is dominated by gastrointestinal effects: nausea, loose stools, constipation, reflux and fatigue feature in the trials for each. These are typically at their most noticeable when starting or moving up a dose, and they often settle within a week or two as the body adjusts.

Because Saxenda is injected daily rather than weekly, some patients find the more frequent dosing schedule harder to maintain over months. That said, tolerability is individual, some people prefer the smaller daily dose steps. Wegovy and Mounjaro both titrate in roughly four-weekly steps, giving the body a longer window to adjust at each level before moving up.

The question of switching between semaglutide and tirzepatide comes up regularly in our consultations, particularly among patients who have plateaued. The head-to-head evidence from the Mounjaro vs Wegovy trial, published in the New England Journal of Medicine in 2025, showed tirzepatide produced greater average weight reduction than semaglutide 2.4mg over 72 weeks, though both achieved clinically meaningful results.

Whichever medicine is under consideration, a prescriber needs to know your full history before recommending one over another. Our clinical team, including our lead prescriber, is introduced on the clinical team page. If you are also considering how Mounjaro compares to Ozempic, that page sets out the differences in active ingredient, licensed dose and intended use. The right choice for you is a clinical decision made with a real person who has read your notes, not a ranking table.

Speak to our prescribers through the free consultation, it's the first step toward knowing which of the licensed options is actually suitable for you.