How much weight loss does Wegovy produce — and what shapes your result?

The numbers behind the average: why 15% is both a fair summary and an incomplete one

The STEP 1 trial is the bedrock of what we know about semaglutide for weight management. Over 68 weeks, participants taking semaglutide 2.4 mg alongside lifestyle changes lost an average of around 15% of their starting body weight, against roughly 2.4% in the placebo group. That gap is large and statistically robust, as the full STEP 1 paper published in the New England Journal of Medicine sets out in detail.

But averages compress a wide spread of individual outcomes. In that same trial, roughly a third of participants on the active dose lost 20% or more of their body weight, while a meaningful minority lost less than 5%. Neither of those extremes is unusual or a sign that the medicine is failing; they reflect genuine biological variation in how people respond to GLP-1 receptor agonists.

The practical implication is that 15% is a reasonable expectation to hold lightly, not a guarantee. If you are considering treatment, knowing the average is useful. Knowing the factors that push individual results higher or lower is more useful still, and that is what a prescriber works through with you during assessment.

For a closer look at how the semaglutide dose schedule relates to outcomes, the page on semaglutide amounts for weight loss covers the titration pathway and what each stage is designed to achieve.

The factors that determine where your result sits within that range

Several things reliably shape individual outcomes on Wegovy, and most of them can be anticipated before treatment starts. Dose reached matters significantly: the 2.4 mg maintenance dose produced the trial results above, but not everyone tolerates titration that far. Gastrointestinal side effects (nausea, loose stools, reduced appetite causing inadequate nutrition) sometimes mean a prescriber keeps someone at a lower dose for longer. That is clinically sensible, but it does affect the eventual weight loss trajectory.

Diet and activity alongside treatment are not optional extras. The trial participants followed a reduced-calorie diet and increased physical activity; the medicine's effect on appetite makes that easier to sustain, but it does not replace the lifestyle component. Protein intake in particular becomes important when eating less, maintaining muscle mass while losing fat is a clinically distinct goal from simply seeing the number on the scales fall.

How long treatment continues also matters. Weight loss in trials does not plateau at eight weeks; it continues to accumulate across the full duration. People who stop early (because of cost, side effects or other reasons) will typically have lost less than the trial average at the point they stop. NICE guidance on semaglutide recommends reviewing whether to continue if less than 5% weight loss has occurred after six months at the maintenance dose, which is a useful benchmark to understand before starting.

Starting BMI plays a smaller role than many assume: people with a higher starting weight often lose a greater absolute number of kilograms, while the percentage figure can look similar or even slightly lower. Age, sex, and underlying metabolic health all contribute to variation as well. A prescriber cannot tell you precisely where your result will fall, but they can assess these factors and discuss realistic expectations.

The 7.2 mg dose and where results are heading

Since January 2026, Wegovy's licensed maximum dose in the UK has been 7.2 mg rather than 2.4 mg. The MHRA approved the higher dose following trial data showing around 20.7% average weight loss over 72 weeks, notably closer to tirzepatide results than the earlier semaglutide figures. On 14 April 2026 the MHRA also approved a dedicated single-dose 7.2 mg pen, a device designed to simplify the weekly injection for people who reach that maintenance level.

This is a meaningful development, because it means the gap between semaglutide and tirzepatide in terms of average outcomes is considerably narrower than comparisons made before 2026 would suggest. That said, reaching 7.2 mg requires full titration over many months from the 0.25 mg starting dose, and the higher dose comes with its own tolerability considerations. Whether the 7.2 mg dose is appropriate for any individual is entirely a clinical decision.

For a broader comparison of how Wegovy's results sit alongside other licensed weight-loss treatments, the Wegovy weight loss overview pulls together the evidence in one place. And if you are weighing up semaglutide against tirzepatide specifically, the semaglutide weight loss page covers the SURMOUNT-5 head-to-head trial data.

On the question of what treatment costs and what a legitimate price includes, the Wegovy treatment and cost page sets out the full picture, including what is and is not bundled into private prescription pricing.

What an honest conversation with a prescriber looks like before you start

Deciding whether to start Wegovy is not purely a question of how much weight you want to lose. It is a clinical decision that weighs your current health, your BMI, any conditions that affect eligibility, the medicines you already take, and your own goals, which may include blood pressure, joint health or energy levels rather than a specific number on the scales.

The NICE technology appraisal for semaglutide (TA875) sets out the eligibility criteria that govern NHS access, and the thresholds for private prescribing follow the licensed indications closely. Adults with a BMI of 30 or above, or 27 or above with a relevant weight-related condition such as hypertension, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea, may be clinically suitable. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance.

A good prescriber will also be direct about what Wegovy cannot do: it does not produce results in isolation, it does not suit everyone medically, and it is not a decision to make based on the trial average alone. Pausing to assess that properly (even if you are eager to start, perhaps because payday has just landed and you are ready to commit) is the service doing its job, not creating unnecessary delay.

You can read more about what Wegovy is and how it works, explore the full range of licensed weight-loss treatment options, or learn about how to get Wegovy from a regulated UK pharmacy. Our clinical team reviews every consultation personally, not software. If you want to understand whether Wegovy is appropriate for your situation, the right starting point is checking your eligibility through a free consultation.