Wegovy before and after: what the clinical evidence shows

What the STEP 1 data shows about before-and-after timelines

The headline figure from STEP 1 (roughly 15% average weight loss) tells only part of the story. The trial ran for 68 weeks, and the trajectory mattered as much as the endpoint. Participants lost weight progressively: the curve was steepest in the first 20 weeks and continued, more gradually, through to the final measurements. By week 20, average loss was already meaningful, but it had not plateaued. That pattern is worth holding in mind when people compare their own progress against someone else's photographs online.

The 15% average also spans a wide range. Some participants in the semaglutide group lost considerably more; others less. Around a third of those on the active dose lost 20% or more of their starting weight. Those outcomes were associated with reaching and sustaining the full 2.4mg maintenance dose alongside the dietary and activity support built into the trial protocol. A closer look at Wegovy weight-loss before and after data sets out how the distribution of results looked across the trial population.

The MHRA's more recent approval of a 7.2mg dose adds a further chapter. Trials at that dose reported approximately 20.7% average weight loss over 72 weeks, narrowing the gap with tirzepatide's results in the SURMOUNT programme. The 7.2mg pen received a dedicated single-dose approval on 14 April 2026 for adults with a BMI of 30 or above.

Why individual before-and-after results differ from trial averages

Trial participants follow a structured protocol, monitored dose increases, regular check-ins, consistent lifestyle support. That structure tends to produce better adherence than the messy reality of everyday life. It is one reason the per-protocol figures (participants who followed the regimen fully) in Wegovy trials are higher than the intention-to-treat averages quoted in headlines.

In practice, results are shaped by factors a clinical trial controls for but real life does not: how quickly someone tolerates dose increases, whether they reach the full maintenance dose, their starting metabolic picture, diet quality, activity levels, and how long they continue treatment. Stopping Wegovy typically leads to weight returning, a finding the STEP 4 withdrawal study documented clearly. Treatment is generally considered long-term, not a short course. The full semaglutide overview covers what happens at each stage of treatment in more detail.

One practical habit worth building early: weigh yourself at the same time on the same day each week rather than daily, morning, before eating, after using the bathroom. Daily fluctuations of 1–2kg are normal and tell you almost nothing useful; weekly readings plotted over time show the actual trend. If you are also thinking through the logistics of your injection routine, our guide on whether you can take Wegovy before bed explains how timing your dose in the evening fits with the medicine's tolerability profile.

Before and after photographs: what they show and what they leave out

The before-and-after images that circulate on social media carry a real problem: selection bias. People who see dramatic results are far more likely to post. People whose results were more modest, or who found the treatment difficult to tolerate, rarely photograph themselves for public comparison. The result is a curated picture that systematically overstates what an average person should expect.

That is not scepticism about the medicine, the trial evidence is robust, published in peer-reviewed journals, and assessed by both the MHRA and NICE in their appraisal of semaglutide (TA875). It is scepticism about photographs as a data source. A 15% average loss on a person starting at 100kg means 15kg. On a person starting at 80kg it means 12kg. The visual difference depends on height, body composition, and where fat is distributed, none of which a photograph captures objectively.

The semaglutide before and after question is ultimately best answered not by images but by understanding what the medicine does pharmacologically: it activates GLP-1 receptors involved in appetite signalling and gastric emptying, reducing how much people feel like eating. The different forms of semaglutide available in the UK (including the recently approved oral tablet) work through the same mechanism, though their licensed doses and trial profiles differ.

Eligibility, NHS access and the private route

NICE's guidance on semaglutide (TA875) sets out NHS eligibility: adults with a BMI of 35 or above plus at least one weight-related condition, used within a specialist weight management service for a maximum of two years. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. NHS waiting lists for specialist services are often long, and not everyone meets the criteria at the current phase of rollout.

For people exploring options, the Wegovy treatment page covers how private prescribing works and what clinical assessment involves. Private treatment through a regulated online pharmacy requires the same prescription process, a prescriber evaluates your health, confirms suitability, and determines the starting dose. For context on what a private course typically costs and what a legitimate price should include, the guide to buying Wegovy online in the UK sets out what to look for and what to avoid. If you are ready to find out whether treatment suits your situation, you can check your eligibility with our prescribers through a free consultation. After a clinical review, if treatment is approved, dispatch is the same day and delivery is free to your door the next working day.