Short answer: Wegovy (semaglutide) worked for most people in its trials, though not for everyone. In the main trial, STEP 1 (New England Journal of Medicine, 2021), adults with a BMI of 30 or more, or 27 or more with a weight-related condition, and without diabetes lost an average of 14.9% of their body weight over 68 weeks on Wegovy 2.4mg, against 2.4% on placebo, counting everyone who started treatment, alongside a reduced-calorie diet and more physical activity. In STEP UP (Lancet Diabetes and Endocrinology, 2025), adults with a BMI of 30 or more and without diabetes lost an average of 18.7% over 72 weeks on the higher 7.2mg dose, against 15.6% on 2.4mg and 3.9% on placebo in the same trial, counting everyone who started treatment. These were separate trials in different groups of people, so the figures are not a direct comparison. Individual results vary. The UK product information says that if you have not lost at least 5% of your starting weight after 6 months on treatment, a decision is needed on whether to continue (SmPC, section 4.2), and NICE says to consider stopping at that point (TA875, recommendation 1.2).
This guide sets out the Wegovy weight loss results in the UK product information and the published STEP trials of semaglutide, as of October 2026: how much weight people lost on each dose, how many reached each milestone, why results differ and what happens when people stop. The week-by-week view is in how long Wegovy takes to work, and our guide to what Wegovy is and how it works explains how the medicine acts on appetite.
Does Wegovy work?
For most people in its trials, yes. In STEP 1 (Wilding and colleagues, New England Journal of Medicine, 2021), 83.5% of people on Wegovy 2.4mg lost at least 5% of their body weight over 68 weeks, against 31.1% on placebo, counting everyone who started treatment, as the UK product information reports it. Individual results vary.
STEP 1 randomly assigned 1,961 adults, two to one, to a weekly injection of Wegovy or a placebo for 68 weeks, with the dose built up from 0.25mg over the first 16 weeks. All had a BMI of 30 or more, or 27 or more with high blood pressure, raised cholesterol or blood fats, obstructive sleep apnoea or cardiovascular disease, and none had diabetes. Its licence covers a similar group of adults (SmPC, section 4.1).
Who Wegovy may suit through Solira
Treatment may be suitable if you're aged 18–85 and have a BMI of 30 or above, or a BMI of 27–29.9 alongside one of the following: high blood pressure, raised cholesterol or blood fats, obstructive sleep apnoea, cardiovascular disease, prediabetes, or type 2 diabetes.
Not sure of your BMI? Use our BMI calculator.
Everyone in STEP 1, including the placebo group, was asked to eat 500 calories a day less than they needed and to do 150 minutes of physical activity a week (SmPC, section 5.1). So the results are for Wegovy alongside those changes, not instead of them. The UK product information also reports a smaller waist and lower systolic blood pressure on Wegovy than on placebo in the same trial.
Our pharmacist's advice
Treatment works alongside a reduced-calorie diet and regular activity. Aim for at least 150 minutes a week. Weight loss naturally slows over time, and stopping treatment without keeping lifestyle changes commonly leads to weight regain, so we review you regularly and plan any stop together.
How much weight can you lose on Wegovy?
On the usual 2.4mg dose, people in STEP 1 (New England Journal of Medicine, 2021) lost an average of 14.9% of their body weight over 68 weeks, against 2.4% on placebo, counting everyone who started treatment. They started at an average of 105.4kg, and on the same basis the average loss was 15.3kg, against 2.6kg on placebo. Individual results vary. How much weight you will lose cannot be known in advance: it depends on your dose, your health and how long you stay on treatment.
The table sets out the main Wegovy study results for weight, from four of the semaglutide trials in the UK product information. In each, the average counts everyone who started treatment, whether or not they kept taking it (SmPC, section 5.1):
| Trial | Who took part | Dose and length | Average weight lost on Wegovy | Average on placebo |
|---|---|---|---|---|
| STEP 1 (New England Journal of Medicine, 2021) | 1,961 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, without diabetes | 2.4mg, 68 weeks | 14.9% | 2.4% |
| STEP 2 (Lancet, 2021) | 1,210 adults with type 2 diabetes and a BMI of 27 or more (404 of them on 2.4mg) | 2.4mg, 68 weeks | 9.6% | 3.4% |
| STEP 5 (Nature Medicine, 2022) | 304 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, without diabetes | 2.4mg, 104 weeks | 15.2% | 2.6% |
| STEP UP (Lancet Diabetes and Endocrinology, 2025) | 1,407 adults with a BMI of 30 or more, without diabetes | 7.2mg or 2.4mg, 72 weeks | 18.7% on 7.2mg, 15.6% on 2.4mg | 3.9% |
These were separate trials in different groups of people, so the figures are not a direct comparison. Individual results vary.
How many people lose weight on Wegovy?
Most people on Wegovy 2.4mg in STEP 1 (New England Journal of Medicine, 2021) lost at least 5% of their body weight over 68 weeks, and nearly half lost at least 15%, counting everyone who started treatment, as the UK product information reports it (SmPC, section 5.1). Individual results vary. These are the shares at week 68:
| Weight lost by week 68 | People on Wegovy 2.4mg | People on placebo |
|---|---|---|
| At least 5% of body weight | 83.5% | 31.1% |
| At least 10% | 66.1% | 12.0% |
| At least 15% | 47.9% | 4.8% |
| At least 20% | 30.2% | 1.7% |
STEP 1, Wilding JPH et al. NEJM 2021, as the UK product information reports it (Wegovy SmPC, section 5.1, revised September 2026), counting everyone who started treatment. Individual results vary.
Even on placebo, with the same diet and activity advice, some people reached each milestone: the gap between the two groups is what the trial credits to the medicine.
Wondering whether Wegovy is suitable for you? Answer a few questions about your health, your weight and any medicines you take. A GPhC-registered pharmacist reviews every consultation.
Check your eligibilityDoes Wegovy work for everyone?
No. In STEP 1 (New England Journal of Medicine, 2021), 83.5% of people on Wegovy 2.4mg had lost at least 5% of their body weight by week 68, counting everyone who started treatment, so about 1 in 6 had not. Individual results vary.
A slow start does not always mean Wegovy will not work for you. The UK product information reports that in STEP 1 (New England Journal of Medicine, 2021), of the people treated with 2.4mg who had not lost 5% of their weight after about 6 months (28 weeks), 40.5% had done so by week 68 (SmPC, section 5.1). Individual results vary. The product information also says weight loss was shown regardless of age, sex, starting weight, BMI, type 2 diabetes or kidney function.
Your pharmacist reviews your progress with you, at the point the UK product information sets: if you have not lost at least 5% of your starting weight after 6 months on treatment, a decision is needed on whether to continue, weighing up the benefits and risks for you (SmPC, section 4.2). NICE's guidance for the NHS uses the same point (TA875, recommendation 1.2). For someone who starts at 100kg, 5% is 5kg. The review can look at your dose, how you inject and store your pens, or a different medicine. If your weight has stalled, see why am I not losing weight on Mounjaro or Wegovy.
How much more weight do you lose on Wegovy 7.2mg?
In STEP UP (Wharton and colleagues, Lancet Diabetes and Endocrinology, 2025), adults with a BMI of 30 or more and without diabetes lost an average of 18.7% of their body weight over 72 weeks on 7.2mg, against 15.6% on 2.4mg and 3.9% on placebo, counting everyone who started treatment: 3.1 percentage points more on 7.2mg than on 2.4mg. Had everyone stayed on treatment, STEP UP's estimated averages were 20.7% on 7.2mg and 17.5% on 2.4mg (SmPC, section 5.1). Individual results vary.
The higher dose is not for everyone on Wegovy. The UK product information allows it, if needed, for adults with obesity (a BMI of 30 or more), after at least 4 weeks on 2.4mg (SmPC, section 4.2), so from week 21 at the earliest on the usual schedule (patient leaflet, section 3). People using Wegovy with a BMI of 27 to 30 stay at up to 2.4mg. Wegovy 7.2 mg comes as a pack of four single-dose pens, so your whole weekly dose is one injection. You may still see it described elsewhere as three 2.4 mg injections, which was the earlier presentation. Use one 7.2 mg pen for each weekly dose.
Two side effects were more common on the higher dose in STEP UP: altered skin sensation, such as a burning feeling or sensitive skin, reported by 21.6% of people on 7.2mg against 0.3% on placebo, and hair loss, by 5.3% against 1.0% (SmPC, section 4.8). Most of the skin sensation events were mild to moderate and settled on treatment. Your pharmacist reviews you before any increase. More on the higher dose is in our guide to Wegovy 7.2mg.
How soon will you see results on Wegovy?
Results build over months rather than weeks, because the dose starts at 0.25mg once a week and goes up every 4 weeks, to make stomach side effects less likely, until you reach 2.4mg from week 17 (SmPC, section 4.2; patient leaflet, section 3). In STEP 1, weight loss began early and continued throughout the 68 weeks (SmPC, section 5.1), but the product information gives no weight figure for the first month on its own. The week-by-week view is in how long Wegovy takes to work.
What affects how much weight you lose on Wegovy?
In the trials, the dose, staying on treatment and type 2 diabetes all made a difference, every result came alongside a reduced-calorie diet and more activity, and weight loss happened whether or not people felt sick.
- Reaching your maintenance dose. The trial figures are for people assigned to 2.4mg, or to 7.2mg in STEP UP. If stomach side effects are significant, the UK product information allows a dose step to be delayed, or the dose lowered to the previous one (SmPC, section 4.2), so some people reach 2.4mg later than week 17.
- Staying on treatment. In STEP 1 (New England Journal of Medicine, 2021), 17.1% of people on Wegovy stopped it for good during the trial. Counting everyone who started treatment, the average was 14.9%; had everyone stayed on treatment, the estimated average was 16.9% (SmPC, section 5.1). Individual results vary.
- Type 2 diabetes. The average was lower in STEP 2, the trial in adults with type 2 diabetes, than in the trials of people without diabetes: see the table above and the note under it.
- What you eat and how active you are. Each trial measured weight loss on treatment alongside a reduced-calorie diet and more physical activity, which everyone, on placebo too, was asked to follow. See what to eat on Wegovy.
- Side effects are not a sign. Feeling sick does not mean Wegovy is working: the UK product information says weight loss happened whether or not people had nausea, vomiting or diarrhoea (SmPC, section 5.1). How to manage them is in Wegovy side effects.
- You. Every figure on this page is an average across many people. Some lose more and some lose less, and no one can say in advance which you will be.
Do you lose more weight on Wegovy or Mounjaro?
On average, people lost more on Mounjaro: in SURMOUNT-5 (Aronne and colleagues, New England Journal of Medicine, 2025), a 72-week trial that compared the two directly in 751 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, and without diabetes, average weight loss on the highest dose each person could tolerate was 20.2% on tirzepatide (Mounjaro, 10mg or 15mg) and 13.7% on semaglutide (Wegovy, 1.7mg or 2.4mg), counting everyone who started treatment: the trial's main result. Had everyone stayed on treatment, the estimated averages were 21.6% on tirzepatide and 15.4% on semaglutide, the figures the UK product information for Mounjaro gives for this trial (Mounjaro SmPC, section 5.1). Individual results vary. The trial was open-label, so people knew which medicine they were taking, and it was funded by Eli Lilly, which makes Mounjaro.
Different medicines suit different people, and a GPhC-registered pharmacist reviews which treatment is suitable for you. The weight loss medicines we supply are set side by side on our weight loss page. The full comparison is in Mounjaro vs Wegovy, and the Mounjaro trial results in our guide to how much weight you can lose on Mounjaro.
What happens to your results if you stop Wegovy?
Weight usually comes back after Wegovy is stopped, though on average not all of it within the year that was studied. In the STEP 1 trial extension (Wilding and colleagues, Diabetes, Obesity and Metabolism, 2022), 327 adults who had completed the 68 weeks were followed for a year after the medicine and the trial's diet and activity programme stopped. Those who had taken semaglutide 2.4mg had lost 17.3% of their weight by week 68; by week 120 they had regained 11.6 percentage points, ending 5.6% below their starting weight, against 0.1% below for the placebo group. These figures cover just the people in the extension, and its analyses were exploratory. Individual results vary.
In STEP 4 (Rubino and colleagues, JAMA, 2021), 803 adults who had reached 2.4mg and lost an average of 10.6% during a 20-week run-in on semaglutide were randomly assigned to carry on or switch to placebo, with diet and activity advice in both groups. Over the next 48 weeks, weight rose by an average of 6.9% in those switched to placebo, while those who carried on lost a further 7.9%, counting everyone randomly assigned at week 20. Individual results vary.
These were separate trials in different groups of people, so the figures are not a direct comparison. Individual results vary.
How we review your treatment
We'll pause or stop treatment if it isn't working for you (less than 5% weight loss after a fair trial at your best-tolerated dose), if side effects persist despite adjusting, if your BMI falls below 20, or if you become pregnant. Treatment is reviewed regularly, and if longer-term therapy beyond our service is right for you, we'll help you transition to a prescriber-led pathway.
Thinking of stopping? Talk to your pharmacist first, so the stop is planned. What happens to appetite and weight afterwards is in our guide to coming off Wegovy.
Are the Wegovy tablets' results the same?
The tablets were tested in their own trial, so their results cannot be compared directly with the injection's. In OASIS 4 (New England Journal of Medicine, 2025), 307 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, and without diabetes took Wegovy tablets 25mg or placebo once a day for 64 weeks. Those on the tablets lost an average of 13.6% of their body weight, against 2.2% on placebo, counting everyone who started treatment (Wegovy tablets SmPC, section 5.1). The injection's average in STEP 1 (New England Journal of Medicine, 2021) was 14.9% over 68 weeks, on the same basis. These were separate trials in different groups of people, so the figures are not a direct comparison. Individual results vary. How the tablets' results build over time is in Wegovy pill results.