What the Clinical Trials for Wegovy Found — and What That Means for You

You've seen the trial statistics, here's the study behind them

Picture yourself, six months ago, sitting in front of a screen reading something like "participants lost up to 15% of body weight." It sounds striking. But what did the trial actually involve? STEP 1 recruited around 1,961 adults with a BMI of 30 or above (or 27 and above with a weight-related condition such as hypertension or high cholesterol) and no diagnosis of type 2 diabetes. Participants received either semaglutide 2.4 mg weekly or a placebo, alongside a reduced-calorie diet and increased physical activity, for 68 weeks. The semaglutide group lost an average of roughly 15% of their starting body weight; the placebo group lost around 2.4%. That gap (real, consistent, statistically robust) is why those results reshaped prescribing conversations across the UK. The trial was blinded, randomised and controlled, which is the gold standard for this kind of evidence. Importantly, results were averages: some participants lost more, some less. That variance matters as much as the headline figure, and it's one reason a prescriber's role doesn't end at the prescription.

For a fuller picture of how the semaglutide evidence base developed across multiple trials, the Wegovy clinical trials overview sets out each study in context.

What happened when researchers increased the dose to 7.2 mg

The STEP programme established 2.4 mg as the standard maintenance dose, but researchers continued testing higher doses. On 14 April 2026 the MHRA approved a dedicated single-dose 7.2 mg pen for adults with a BMI of 30 or above, not for the cardiovascular indication and not for BMI below that threshold. Trial data reported around 20.7% average weight loss over 72 weeks at 7.2 mg, narrowing the gap with tirzepatide 15 mg results considerably. The titration schedule still starts at 0.25 mg; 7.2 mg is the ceiling, reached over several months of dose-stepping supervised by a prescriber. Evidence behind the 7.2 mg dose is worth reading if you're already established on treatment and wondering what the higher-dose approval means in practice. One practical note: like all doses of Wegovy, the pen lives in the fridge until the week you use it, storage instructions in the Patient Information Leaflet take precedence over anything you read elsewhere.

The MHRA's announcement on the 7.2 mg pen approval sets out the full regulatory detail if you want the official source.

Trial participants vs. the real world: what the evidence can and cannot tell you

Clinical trials are deliberately controlled. Participants are screened carefully, followed up regularly, given structured lifestyle support, and often more motivated than average. Real-world results sometimes differ, better in some studies where people have extra support, lower in others where adherence drops. None of that undermines the trial data, but it does mean that sitting with a prescriber and discussing your specific health picture, medications, and history is the step that bridges the gap between a population average and what you might reasonably expect. That's not a caveat buried in small print. It's the actual point. The semaglutide weight-loss trial evidence page covers the broader landscape of studies, including STEP 2 (people with type 2 diabetes) and STEP 4 (maintenance after withdrawal). On the Wegovy treatment page you'll find how this evidence feeds into eligibility criteria used in the UK today.

Moving from trial data to a prescription: how this works in the UK

Wegovy is a prescription-only medicine in the UK. The trial evidence is what the regulator, the MHRA, reviewed before granting a UK licence; NICE's appraisal of semaglutide (TA875) then assessed that evidence against cost-effectiveness criteria for NHS commissioning. The NICE recommendation comes with conditions, a maximum two-year course, within a specialist weight management service, for adults with a BMI of 35 or above and at least one comorbidity, though lower thresholds apply for certain ethnic backgrounds. If you don't meet NHS criteria or would rather not wait, a private prescription is the lawful alternative, provided a prescriber makes that assessment properly. On how to get a Wegovy prescription in the UK, we've covered the process from first consultation to delivery. Cost context is part of most people's decision too, what Wegovy actually costs in the UK sets out what you'd typically encounter, including what legitimate pricing includes and why a suspiciously low price is a reason to pause. At nume, a GPhC-registered Independent Prescriber reads your consultation the same day, not software, a real clinician. If treatment is appropriate, it's dispatched the same day and arrives the next working day. Speak to our prescribers if you'd like to understand whether Wegovy is suitable for you.