Is Liraglutide Better Than Tirzepatide for Weight Loss?

What does the trial evidence say about weight loss with each medicine?

Published data put tirzepatide ahead of liraglutide by a considerable distance. In the SURMOUNT-1 trial, tirzepatide at its 15 mg maintenance dose produced an average body-weight reduction of around 20–21% over 72 weeks in adults without type 2 diabetes, a figure reported in the New England Journal of Medicine. Liraglutide (as Saxenda) produced average losses of roughly 5–8% in its pivotal trials over a similar duration, though direct head-to-head data between these two specific agents is limited.

The mechanism difference matters here. Liraglutide activates only the GLP-1 receptor, slowing stomach emptying and reducing appetite through one hormonal pathway. Tirzepatide adds GIP receptor activation on top of that, which appears to amplify the effect on appetite and body weight. In the SURMOUNT-5 trial (a direct comparison of tirzepatide against semaglutide 2.4 mg, the strongest injectable GLP-1 currently available) tirzepatide still came out ahead over 72 weeks, as NICE noted in its appraisal of tirzepatide (TA1026). Liraglutide sits below semaglutide in the GLP-1 hierarchy of effect, so the gap against tirzepatide is wider still.

One practical note: tirzepatide is injected once a week. Liraglutide requires a daily injection. For many people, weekly dosing is simply easier to build into a routine, the pen goes in the fridge door and you deal with it the same day each week rather than every morning.

Is liraglutide (Saxenda) licensed for weight loss in the UK, and does nume prescribe it?

Saxenda (liraglutide 3 mg) does hold a UK licence for weight management in adults with a BMI of 30 or above, or 27 and above where at least one weight-related condition is present. It is a prescription-only medicine; a GP or other authorised prescriber must assess suitability before it can be supplied. The NHS medicines page for tirzepatide sets out the equivalent position for Mounjaro.

Saxenda is not the same as Ozempic or Victoza. Both of those are also liraglutide-based or semaglutide-based, but licensed for type 2 diabetes, not weight loss. That distinction matters when you are comparing products online, because the names are sometimes used loosely.

nume does not dispense liraglutide or Saxenda for weight loss. The weight-loss medicines prescribed through our pharmacy are tirzepatide (Mounjaro) and Wegovy (semaglutide). Both carry MHRA authorisation for weight management. If you are currently on Saxenda and considering a switch, our prescribers can assess that as part of your consultation; there is practical guidance on switching from liraglutide to tirzepatide that is worth reading first.

Do liraglutide and tirzepatide share the same side-effect profile?

In broad terms, yes, both produce a GI-led side-effect pattern. Nausea, loose stools, constipation, indigestion and reduced appetite are common with either. These effects tend to be most noticeable when starting or moving to a higher dose, and they often settle within the first couple of weeks. Injection-site reactions and fatigue appear with both.

There are some differences worth knowing. Tirzepatide's dual mechanism does not appear to produce a markedly different side-effect character, but individual responses vary. The MHRA Drug Safety Update index carries the most current safety communications for GLP-1 medicines, including a January 2026 update on acute pancreatitis risk, which applies across this class. Severe or persistent stomach pain that spreads to the back warrants prompt medical attention regardless of which medicine you take.

For a fuller account of what the evidence says about how these agents compare beyond weight loss (including cardiovascular and metabolic effects) our page on the difference between liraglutide and tirzepatide goes deeper. Anyone weighing up options that go further than current licensed medicines may also find the retatrutide comparison useful context.

So which medicine is actually right for you?

The trial data point in one direction: if you want a detailed look at how tirzepatide compares with liraglutide across the key clinical measures, that page sets out the evidence side by side, and the short version is that tirzepatide produces greater average weight loss, taken once a week rather than daily, and it is what the evidence underpinning NICE's recommendation (TA1026) is built on. But trial averages describe populations, not individuals. Your medical history, any medicines you already take, your BMI, and any conditions you have all shape which treatment a prescriber would consider appropriate.

That is exactly what a consultation at nume is for. A GPhC-registered Independent Prescriber (not a bot working through a checklist) reads your answers and makes a clinical judgement the same day. If tirzepatide is not suitable for you, they will say so, and our page covering whether anything is currently better than tirzepatide for weight loss is a useful read if you want to understand what other options exist. If you are coming from Saxenda and want to understand the transition, that can also be assessed; see our overview of weight-loss treatments for the broader picture. Which medicine suits you is a decision our prescribers make with you, not for you.

Ready to find out whether Mounjaro is clinically appropriate for you? Start your free consultation, it takes a few minutes and our team reviews it the same day.