Semaglutide or liraglutide for weight loss: what the UK evidence says

Step 1: understand what each medicine is and how it works

GLP-1 receptor agonists mimic a gut hormone released after eating. They slow the rate at which food leaves the stomach, reduce appetite signals in the brain, and help regulate blood sugar. Both semaglutide and liraglutide act on the same receptor, which is why they're often grouped together, but that's roughly where the similarity ends in practice.

Liraglutide (the active ingredient in Saxenda) was the earlier medicine. It requires a daily injection, has a shorter half-life, and needs to be titrated from 0.6 mg up to a maintenance dose of 3 mg over several weeks. Semaglutide has a longer half-life that supports once-weekly dosing, which most people find easier to sustain. You can read more about the key differences between liraglutide and semaglutide in detail, including the molecular reasons their dosing schedules differ so sharply. The NHS medicines page for semaglutide covers the once-weekly injection schedule and what patients should expect at each stage.

Step 2: look at what the trial evidence actually shows

The gap in trial results between the two medicines is substantial. In the STEP 1 trial, published in the New England Journal of Medicine, adults with obesity who used semaglutide 2.4 mg weekly alongside lifestyle changes lost around 15% of body weight on average over 68 weeks, roughly three times the loss seen in placebo groups. Liraglutide 3 mg trials reported average losses closer to 5–8% over a similar period, with higher discontinuation rates linked partly to the daily injection burden.

That difference is not merely statistical. For someone weighing 100 kg, 15% means 15 kg; 5–8% means 5–8 kg. Both represent clinically meaningful changes, but the practical outcomes diverge considerably. For a fuller breakdown of semaglutide's weight-loss results across different trial arms, the evidence page covers the STEP programme in detail. The NICE appraisal of semaglutide (TA875) is also worth reading if you want to understand how the regulator weighed that evidence in recommending Wegovy within the NHS.

Step 3: check which medicines are actually licensed for weight loss in the UK right now

This is where the practical decision gets simple. Semaglutide as Wegovy (both the weekly injection and the newer daily tablet, approved by the MHRA in June 2026 as the first oral GLP-1 medicine licensed for weight management in the UK) holds a current UK licence for weight loss, and you can find a full guide to AXA Wegovy coverage and access routes if insurance or employer schemes are part of your funding picture. Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist made by Eli Lilly, is also UK-licensed and NICE-recommended for weight management.

Liraglutide as Saxenda also holds a UK marketing authorisation for weight management, but it is not a medicine that nume dispenses. If your search brought you here because you'd heard liraglutide mentioned alongside semaglutide and wanted to understand your options, the licensed medicines available through our pharmacy are Wegovy and Mounjaro. You can explore both on the treatment options page and see which might suit your situation. If you're curious about how clinicians weigh liraglutide against semaglutide, that comparison covers the evidence and practical factors in full.

One point worth noting: Ozempic is also semaglutide, but it carries a licence for type 2 diabetes, not weight management. Rybelsus is oral semaglutide licensed for diabetes at lower doses (3 mg, 7 mg, 14 mg), which are entirely separate from the Wegovy tablet weight-loss schedule. Conflating these products is a common source of confusion, so it's worth being clear on which licence applies to which brand before beginning any treatment.

Step 4: know what a legitimate clinical pathway looks like

Whichever licensed medicine turns out to be clinically appropriate, the route is the same: a prescriber assesses your health history, current BMI, any relevant conditions, and any medicines you already take. At nume, that assessment is carried out the same day you submit your consultation, by a GPhC-registered Independent Prescriber, not an automated system. You can verify our pharmacy on the GPhC register (premises number 9012878).

If cost is a factor in your thinking, the Wegovy pricing page explains honestly what drives private prescription costs and what a legitimate price should include. The short version: a prescription-only medicine priced without a clinical assessment attached is a red flag, not a bargain. Some people also ask about NHS access, our Wegovy overview covers current NHS eligibility thresholds and why waiting lists remain long for most people outside specialist services.

Keep your pen in the fridge door so the weekly routine is impossible to forget. It's a small practical habit, but the people who stay consistent with treatment tend to be the ones who've built the injection into a predictable slot in the week. Our prescribers are available seven days a week if questions come up after you start.