Liraglutide or Tirzepatide: What the Evidence Actually Says

The biggest misconception: they're the same class, so they must work the same way

Most people asking about liraglutide or tirzepatide have heard both described as "GLP-1 injections" and assume the difference is mainly brand name or dose. It isn't. Liraglutide binds only to GLP-1 receptors, slowing gastric emptying and reducing appetite through one hormonal signal. Tirzepatide binds to both the GLP-1 and GIP receptors, a dual mechanism that has, in clinical trials, produced considerably larger average weight reductions than any single-receptor GLP-1 medicine at its approved dose.

In the SURMOUNT-1 trial, published in the New England Journal of Medicine, adults taking 15mg tirzepatide lost around 20–21% of body weight on average over 72 weeks alongside a reduced-calorie diet and increased activity. Liraglutide's trial data for weight management showed roughly 5–8% average loss over 56 weeks at its licensed dose, a meaningfully different result.

This isn't a slight against liraglutide. It was, for several years, one of the more effective licensed options available. The arrival of weekly GLP-1 and dual-agonist medicines has simply shifted what "effective" looks like in this field. Understanding that shift is the first step to asking the right question of a prescriber.

What liraglutide is, and why it's not what nume prescribes

Liraglutide for weight management is marketed in the UK as Saxenda, manufactured by Novo Nordisk. It requires a daily subcutaneous injection, titrated up over several weeks to the 3mg maintenance dose. It is licensed for adults with a BMI of 30 or above, or 27 and above with at least one weight-related condition, and is taken alongside dietary and activity changes.

A question our prescribers hear most weeks is whether switching from Saxenda to Mounjaro is straightforward. The honest answer is that it requires a fresh clinical assessment: the medicines have different mechanisms, different titration schedules, and different contraindication profiles. A prescriber needs to review the whole picture rather than simply swap like for like.

Liraglutide is not a medicine nume currently dispenses. If you are already taking it through another service, the frequently asked questions section of our site covers how transfer patients are reviewed, and our team can help point you in the right direction.

Tirzepatide in the UK: what the licence and NICE guidance actually cover

Tirzepatide (Mounjaro in the UK) received its NICE recommendation for weight management in December 2024 (TA1026), making it the first dual GIP/GLP-1 agonist to reach that milestone in England. NICE's appraisal of tirzepatide recommends it for adults with a BMI of 35 or above and at least one weight-related comorbidity, with lower BMI thresholds applying for some ethnic backgrounds under UK guidance.

The private licence is broader: adults with a BMI of 30 or above, or 27 and above with a qualifying condition such as high blood pressure, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea. Treatment starts at 2.5mg weekly, with the prescriber guiding titration from there; if you want to understand how the lower doses work in practice, our page covering tirzepatide l goes into that in more detail. The pen delivers four weekly doses; storage is in the fridge.

Pricing context is worth mentioning here: Eli Lilly revised Mounjaro's UK list price significantly from September 2025, and the cost of that price change has filtered through to private providers at different rates. Any legitimate price from a registered pharmacy includes the prescription and clinical assessment, not just the medicine itself.

If you want to explore whether tirzepatide suits your situation, the tirzepatide overview on our site covers the mechanism, licensed doses and eligibility criteria in more detail.

What is licensed for weight management in the UK right now

For clarity, the medicines currently licensed by the MHRA for weight management in UK adults are: tirzepatide (Mounjaro), semaglutide injection (Wegovy), semaglutide tablets (Wegovy tablets, approved June 2026), liraglutide (Saxenda) and orlistat. Ozempic, Rybelsus and Victoza are licensed for type 2 diabetes, not for weight management, and should never be sought for that purpose.

nume prescribes Mounjaro and Wegovy (both the injection and the tablet form) for eligible adults following a same-day clinical review by a GPhC-registered Independent Prescriber, and patients who reach the higher end of the titration schedule can find guidance on the upper maintenance supply on our tirzepatide 30 page. Saxenda is not currently part of the service.

If you're trying to decide whether tirzepatide or semaglutide makes more sense for you, the comparison between them is a better starting point than the liraglutide question. The weight-loss treatments overview sets out all the options side by side. Ultimately, which medicine (if any) is right for you is a decision your prescriber makes after a full assessment. Check your eligibility by starting a free consultation with our clinical team.