The average, week by week
These numbers come from STEP 1, the main weight trial of the semaglutide 2.4 mg injection. 1,961 adults without diabetes took it or a placebo for 68 weeks, with diet and activity counselling for everyone (STEP 1, NEJM, 2021).
| Week | Dose that week | Semaglutide 2.4 mg group | Placebo |
|---|---|---|---|
| Week 4 | 0.25 mg | −2.3% | −1.1% |
| Week 8 | 0.5 mg | −4.0% | −1.8% |
| Week 12 | 1 mg | −5.9% | −2.2% |
| Week 16 | 1.7 mg | −7.7% | −2.5% |
| Week 20 | 2.4 mg | −9.5% | −2.8% |
| Week 28 | 2.4 mg | −11.7% | −2.8% |
| Week 36 | 2.4 mg | −13.3% | −3.0% |
| Week 44 | 2.4 mg | −14.6% | −3.2% |
| Week 52 | 2.4 mg | −15.5% | −3.3% |
| Week 60 | 2.4 mg | −15.9% | −3.2% |
| Week 68 | 2.4 mg | −15.6% | −2.8% |
Read off Figure 7 of the US Wegovy label (Wegovy label, FDA, 2026). The chart has no point at week 24; the average was between −9.5% at week 20 and −11.7% at week 28. Week 68 values are the ones printed on the chart. Doses went up every 4 weeks to 2.4 mg by week 16 to 17 (STEP 1, NEJM, 2021). Averages in the trial, not a prediction. Your results will differ.
- Semaglutide 2.4 mg
- Placebo
Digitised from Figure 7 (STEP 1) of the Wegovy US label. Observed average change while in the trial. (Wegovy label, FDA, 2026). Points are read off the published chart, so they can be out by about a quarter of a percentage point. They are average results in the trial, not a prediction. Your results will differ.
Show the numbers
| Week | Semaglutide 2.4 mg | Placebo |
|---|---|---|
| 4 | −2.3% | −1.1% |
| 8 | −4.0% | −1.8% |
| 12 | −5.9% | −2.2% |
| 16 | −7.7% | −2.5% |
| 20 | −9.5% | −2.8% |
| 28 | −11.7% | −2.8% |
| 36 | −13.3% | −3.0% |
| 44 | −14.6% | −3.2% |
| 52 | −15.5% | −3.3% |
| 60 | −15.9% | −3.2% |
| 68 | −15.6% | −2.8% |
The dose alongside
The label steps the injection up every 4 weeks: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, then 2.4 mg from week 17 (Wegovy SmPC, MHRA, 2026) (Wegovy label, FDA, 2026). STEP 1 used the same steps (STEP 1, NEJM, 2021). If a step is not tolerated, the US label says the next one can wait 4 more weeks (Wegovy label, FDA, 2026).
These numbers are for the weekly injection. The Wegovy pill and the newer 7.2 mg dose were tested in other trials and are not charted here. See the Wegovy guide for what each is approved for.
Weeks 1 to 16: the low doses
In STEP 1, feeling sick happened mainly while the dose was going up (STEP 1, NEJM, 2021). Stomach side effects were mostly mild to moderate and usually passed (STEP 1, NEJM, 2021).
Average weight loss during the low doses was about 2% at week 4, 4% at week 8, 6% at week 12 and 7.7% at week 16 (Wegovy label, FDA, 2026).
Weeks 20 to 68: the full dose, then a slowdown
The average kept falling on 2.4 mg: −9.5% at week 20, −11.7% at week 28 and −15.5% at week 52 (Wegovy label, FDA, 2026). The paper says it did not reach its lowest point until week 60 (STEP 1, NEJM, 2021).
The label's chart prints −15.6% at week 68. The paper's headline, which uses a different method, was −14.9% (Wegovy label, FDA, 2026) (STEP 1, NEJM, 2021). More on plateaus.
What the averages hide
At 68 weeks, 86.4% of people on semaglutide had lost at least 5% of their weight, 50.5% at least 15% and 32.0% at least 20% (STEP 1, NEJM, 2021). Some people lost much less.
NICE says to consider stopping semaglutide if less than 5% of the starting weight has been lost after 6 months (NICE TA875, 2023). That is a decision for you and your prescriber.
Make your own week by week.
- Weigh in on the same day each week
- Note your dose for that week
- Measure your waist every few weeks
- Take photos from the same four angles
- Log side effects as they happen
- Compare months, not days
Where these facts come from.
- WEGOVY (semaglutide) injection and tablets, US prescribing information, Novo Nordisk. Revised 6/2026. DailyMed.
- Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med 2021;384:989-1002.
- Wegovy FlexTouch (semaglutide) Summary of Product Characteristics. Revised 09/2026. emc.
- Semaglutide for managing overweight and obesity. NICE technology appraisal guidance TA875. Published 8 Mar 2023, updated 4 Sep 2023.
Checked 25 Oct 2026. Trial figures are average results in the trial, not predictions. Labels change; your prescriber and the leaflet in your pack have the current version.
Pip Body Scan is a personal progress record. It is not a medical device and does not give medical advice, diagnose conditions or recommend doses. Speak to your prescriber or another qualified healthcare professional about symptoms, side effects or changes to your treatment.