Saxenda Compared to Wegovy: Two Very Different Weight-Loss Injections

You've read about both and you're not sure the difference matters

It does matter, and here's why. Saxenda (liraglutide 3mg) and Wegovy (semaglutide 2.4mg) both work on GLP-1 receptors, the gut-hormone pathway involved in appetite signalling and gastric emptying. That shared mechanism sometimes leads people to assume the results are interchangeable. They are not. Liraglutide has a shorter half-life, which is why it needs a daily injection; semaglutide's longer-acting structure means once a week covers it. That distinction shapes everything from the titration schedule to what happens if you miss a dose.

In the SCALE Obesity and Prediabetes trial, liraglutide 3mg produced average weight loss of around 8% over 56 weeks. The STEP 1 trial for semaglutide 2.4mg (published in the New England Journal of Medicine) reported approximately 15% average reduction over 68 weeks. Those trials weren't head-to-head, so direct comparison has limits, and if you want to dig into how Saxenda and Wegovy compare across the key measures, we've covered that in detail. But the direction of evidence is consistent across analyses: semaglutide produces greater average loss at its licensed dose. NICE's appraisal of tirzepatide (TA1026) also references this indirect comparison landscape.

Worth noting: trial averages are population figures. Individual response depends on adherence, lifestyle changes, and whether the titration schedule is tolerated. A 15% average still means a large number of participants lost considerably less, or more. The number to take away is the direction, not the promise.

The practical gap between daily and weekly injections

A question the prescribers at our clinical team hear regularly: does the injection frequency actually make a difference to real-world use? The evidence suggests it does. Adherence data on daily injections for chronic conditions consistently shows a drop-off over months that weekly regimens avoid. Saxenda requires 365 injections a year at maintenance; Wegovy requires 52.

Both medicines start at a low tolerability dose and titrate upward over several months. Saxenda begins at 0.6mg daily and steps toward 3mg; Wegovy begins at 0.25mg weekly and steps toward 2.4mg, with a further licensed option at 7.2mg following MHRA approval of the dedicated 7.2mg single-dose pen in April 2026. Both are injected subcutaneously into the abdomen, thigh or upper arm, rotating sites each time. A practical checking habit worth building: each week before you inject, confirm the pen is clear and colourless, if it looks cloudy or has particles, that's a reason to contact your pharmacy or prescriber before using it.

Neither medicine is a substitute for eating well and moving more. That is not a disclaimer, it's baked into how the licences were granted and how the trials were designed. Both work alongside a reduced-calorie diet and increased physical activity, and both produce less weight loss without those changes in place.

What's actually licensed for weight loss in the UK right now

This matters more than it might seem. Saxenda (liraglutide 3mg) is licensed in the UK for weight management. Wegovy (semaglutide) is licensed for weight management. Those are the two injectable GLP-1 options with that specific licence. Ozempic is also semaglutide, but its UK licence covers type 2 diabetes (not weight loss) and it should not be prescribed or dispensed for that purpose, and people wondering whether Ozempic or Wegovy is more effective will find the licensed distinction matters a great deal to that answer. That distinction matters when someone is comparing products and wondering why similar-sounding medicines carry different labels.

Mounjaro (tirzepatide) is a third option: a dual GIP and GLP-1 receptor agonist, the only one of its kind licensed in the UK for weight management. SURMOUNT-1 data showed average body-weight reduction of around 20–21% at the highest dose over 72 weeks, a meaningfully different scale of result from either liraglutide or semaglutide. Our weight-loss treatment overview covers the licensed options and how they compare.

Saxenda is not dispensed by nume. The treatments we do offer (Wegovy and Mounjaro) are both covered in detail on our Wegovy page and the broader treatment consultation hub. If you're already on Saxenda and want to understand what switching might involve, there's specific guidance on how to move from Saxenda to Wegovy.

Side effects, cost context, and the clinical decision

Both medicines share a gastrointestinal side-effect profile: nausea, loose stools, constipation, indigestion and reduced appetite are the most commonly reported. These tend to peak in the first days after starting or after a dose increase, then ease for most people. The frequency looks similar between liraglutide and semaglutide in trial data, though semaglutide's weekly injection means fewer "day one" spikes. Full detail on what to watch for (including the signs that need same-day medical attention) sits on the NHS semaglutide medicines page.

On cost: Saxenda has been on the market longer and private prices are typically lower per month than Wegovy, particularly at lower doses. But lower cost per injection and greater average weight loss do not point in the same direction here, semaglutide has the stronger result record at a higher private cost. Price is a real consideration, but for a prescription medicine it's not the right place to start. Efficacy, tolerability and your clinical profile come first. A wider look at how Wegovy is priced in the UK private market is worth reading before drawing conclusions.

The honest framing for any wegovy compared to saxenda question is that the evidence favours semaglutide on average weight reduction, the convenience of weekly injecting is meaningful for adherence, and liraglutide has a longer real-world track record. Which of these factors matters most to your situation is a clinical question, not a ranking exercise. If you'd like to explore what's right for you, check your eligibility with our prescribers, there's no charge for the consultation and a real clinician reads every response the same day.