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Start journey Learn moreHow Saxenda and Wegovy compare on mechanism, results and practical use
You've been told both are 'the weight-loss jab', here's what actually separates them
Picture two people sitting in a GP surgery asking the same question: "Should I try Saxenda or Wegovy?" Both drugs activate the GLP-1 receptor, which slows how quickly food leaves the stomach and signals fullness to the brain. The mechanism is genuinely shared. What diverges is the chemistry underneath it.
Saxenda contains liraglutide, which has a half-life of roughly 13 hours, meaning it needs a daily injection to stay effective. Wegovy contains semaglutide, engineered to last about a week in the body, so one injection covers seven days. For most people, injecting once a week rather than every morning is simpler and easier to stay consistent with, particularly around irregular weeks like bank holidays or busy stretches at work.
Wegovy is also the more recent approval. Saxenda was licensed for weight management in the UK before semaglutide arrived, and if you want to understand how semaglutide compares to Saxenda across the key clinical differences, we cover that in detail separately. The NHS medicines information for semaglutide covers both its mechanism and its most commonly reported effects in patient-friendly terms.
What the trial data actually shows: a side-by-side look
The strongest evidence for these two medicines comes from separate large-scale trials, so a head-to-head is technically indirect, though NICE's appraisals have weighed them. The figures below come from those published trials and NICE's guidance.
| Feature | Saxenda (liraglutide) | Wegovy (semaglutide 2.4mg) |
|---|---|---|
| Injection frequency | Once daily | Once weekly |
| Average weight loss in pivotal trial | ~8% body weight (SCALE, 56 weeks) | ~15% body weight (STEP 1, 68 weeks, published in the NEJM) |
| UK licence for weight management | Yes (BMI ≥30 or ≥27 with comorbidity) | Yes (BMI ≥30 or ≥27 with comorbidity) |
| NICE recommended for NHS use | No dedicated TA for weight loss | Yes, NICE TA875, within specialist services |
| Dispensed by nume | No | Yes |
The gap in average weight loss is meaningful. In the STEP 1 trial, around 70% of participants on semaglutide 2.4mg lost at least 10% of their body weight over 68 weeks. Saxenda's SCALE trial, while rigorous, produced a lower average reduction over a shorter period. Neither trial involved the same population, so comparing numbers directly has limits, but NICE's own appraisal process reached the conclusion that semaglutide justifies a recommendation for the NHS, while liraglutide for weight loss does not have an equivalent NICE technology appraisal.
It is also worth knowing that a higher-dose Wegovy pen delivering 7.2mg per week received MHRA approval in April 2026, with trial data showing average weight loss approaching around 20%, narrowing the gap further with tirzepatide. You can read more about the evidence behind Wegovy versus Saxenda in more detail if this comparison is central to your decision.
Side effects: broadly similar profiles, some differences in tolerability
Both medicines share a GI-led side-effect profile. Nausea is the most commonly reported effect with either drug, along with vomiting, diarrhoea, constipation and indigestion. These tend to peak in the early weeks of treatment or after a dose increase, and most people find them manageable as their body adjusts.
Some clinicians and patients report that the daily injection pattern of Saxenda means GI effects can feel more continuous, whereas the once-weekly rhythm of Wegovy gives the body a longer settled period between doses. Individual responses vary considerably, though, and that observation is not a formal clinical finding. The NHS obesity treatment page gives a clear overview of how weight-loss medicines fit into a broader management approach.
Pancreatitis is a serious but infrequent risk with GLP-1 medicines generally. Persistent, severe stomach pain (particularly if it radiates towards the back) warrants urgent medical attention rather than waiting for a scheduled review. Pregnancy, breastfeeding, and trying to conceive are contraindications for both; neither is licensed for under-18s. Any prescriber assessing suitability will go through these factors before a treatment starts.
For a fuller look at how Wegovy sits against other medicines in this class, the Wegovy vs Ozempic page covers a question our prescribers hear regularly.
Saxenda is not available through nume, here is what is
Saxenda is licensed for weight management in the UK and is a legitimate medicine, but it is not dispensed through our pharmacy. If you have been weighing up whether Saxenda or Wegovy is the right fit for weight loss and want to take action today, the treatments available through a nume consultation are Wegovy (semaglutide) and Mounjaro (tirzepatide), both licensed for weight management and both reviewed by our clinical team before any supply.
Mounjaro works differently from either Saxenda or Wegovy: it activates both the GIP and GLP-1 receptors, and in SURMOUNT-5 (the first published head-to-head trial against semaglutide 2.4mg) it produced greater average weight reduction over 72 weeks. You can explore both options on our weight-loss treatments overview and compare what might suit your situation.
Which medicine is right for you is a clinical decision, not a checklist. Our prescribers look at your BMI, health history, any medicines you already take and what you have tried before. If you want a clearer picture of how Saxenda and Wegovy differ on the factors that matter most, that comparison is worth reading before your consultation. If you'd like that conversation, speaking to our prescribers starts with a free consultation, no commitment, no subscription, no pressure.
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