Mounjaro®
Starting from £179.99/mo
Start journey Learn moreWhat the evidence actually shows when you put Wegovy and Saxenda side by side
The trial numbers: where the gap between the two medicines comes from
The most direct comparison comes from the STEP 8 trial, a 68-week head-to-head study in adults with obesity. Participants on semaglutide 2.4mg lost an average of around 15.8% of their body weight, against roughly 6.4% for liraglutide 3mg — a difference that was statistically significant and clinically meaningful. You can read the published findings via the New England Journal of Medicine's semaglutide trial data, which covers the STEP programme in detail. The NICE appraisal of semaglutide for weight management (TA875) also references this comparative evidence in its clinical review.
Neither medicine produces the same result for everyone, biology, starting weight, diet and how consistently someone takes the treatment all shape the outcome. But on the population-level data available, semaglutide's advantage is consistent across the studies, not a one-off finding.
Liraglutide's results in its own pivotal trials averaged around 5–8% body weight reduction at 3mg over 56 weeks, versus placebo. Semaglutide's STEP 1 trial reported an average of roughly 15% over 68 weeks at 2.4mg. The gap is not subtle.
How the two medicines differ in practice
Both work on GLP-1 receptors in the brain and gut, slowing gastric emptying and reducing appetite. Semaglutide does this with a longer molecular half-life, which is why once-weekly dosing is enough. Liraglutide clears the body faster, which is why daily injections are needed, every single day, including weekends and holidays.
That daily commitment matters more than it sounds. Consistency is easier on a weekly rhythm, and there is some evidence that adherence is higher with weekly injections. For anyone who travels regularly or has a Monday-to-Friday routine they find hard to break for health admin, the practical difference between once-daily and once-weekly is real.
Side-effect profiles are broadly similar: nausea, constipation, diarrhoea and indigestion feature in both, most often when starting or increasing the dose. The NHS semaglutide medicines page covers semaglutide's side effects in plain language and is a reliable first reference. Both medicines require titration by a prescriber rather than jumping to the full dose from day one.
UK licensing: what each medicine is actually approved for
| Feature | Wegovy (semaglutide) | Saxenda (liraglutide) |
|---|---|---|
| UK weight-loss licence | Yes (BMI ≥30, or ≥27 with a weight-related condition) | Yes (BMI ≥30, or ≥27 with a weight-related condition) |
| Injection frequency | Once weekly | Once daily |
| Average weight loss in pivotal trial | ~15% over 68 weeks (STEP 1, 2.4mg) [NEJM] | ~5–8% over 56 weeks (SCALE trial, 3mg) |
| Head-to-head result (STEP 8) | ~15.8% average loss | ~6.4% average loss |
| NICE recommendation | TA875 (specialist weight management services) | No NICE weight-management TA |
| Dispensed by nume for weight loss | Yes | No |
Saxenda holds a valid UK licence for weight management, so it is a legitimate option through services that carry it. Wegovy's NICE recommendation (TA875) means it has passed a formal UK health-technology appraisal; liraglutide has not been through that process for weight management. If you want a fuller breakdown of how the two medicines stack up, our page on which is better between Saxenda and Wegovy works through the key differences in more detail, though it reflects NICE's appraisal timeline rather than any safety concern with Saxenda.
What is licensed for weight loss through nume, and how to get it
nume dispenses two licensed weight-loss medicines: Wegovy (semaglutide injection) and Mounjaro (tirzepatide). Mounjaro is the only dual GIP and GLP-1 receptor agonist available in the UK for weight management, and in the SURMOUNT-5 head-to-head trial it produced greater average weight reduction than semaglutide 2.4mg. You can compare them in more detail on our Mounjaro vs Wegovy comparison.
For Wegovy specifically, our Wegovy treatment overview covers the titration schedule, eligibility and how the prescription process works. If cost is a factor in your thinking, the Wegovy cost page sets out what private treatment typically involves and what our single transparent price includes. Neither Saxenda nor Ozempic is available through nume for weight loss; if you have been on Saxenda previously and are wondering whether Wegovy would give you better results than Saxenda, that is something to explore with our prescribers during a consultation, and you may also want to read our guidance on how to switch your Wegovy supplier if you are already on semaglutide elsewhere.
Which of the two medicines available through us would suit you better is not something this page can settle. It depends on your medical history, any other medicines you take, your BMI and weight-related conditions, and how you respond to treatment. That is precisely what the clinical review is for. Our prescribers at the nume clinical team review every consultation personally, and you can find answers to common questions on our FAQs page before you start. When you are ready, speak to our prescribers and we will take it from there.
Looking to start your weight loss journey?
Take a quick eligibility quiz to explore your options and see how we can support you.