STEP 1 and the standard dose
STEP 1 enrolled 1,961 adults with obesity, or overweight with a related condition, and no diabetes. At 68 weeks, average weight change was 14.9% with semaglutide 2.4 mg and 2.4% with placebo, both alongside lifestyle support. These are average changes from starting weight. They do not show the share of people who lost weight.
If you start at 100 kg, 14.9% works out at 14.9 kg. The sum shows what the percentage means. It is no forecast for you. Some people lost more, some lost less and some stopped treatment. One average cannot describe the whole range.
Longer treatment and higher doses
STEP 5 followed people on the standard dose for 104 weeks. Average change was 15.2% with semaglutide and 2.6% with placebo. The result shows weight loss holds while you keep taking the medicine. Do not expect weight to keep falling at the early rate.
STEP UP tested 7.2 mg in adults with obesity. At 72 weeks, its treatment-policy analysis reported 18.7% average loss, against 15.6% for 2.4 mg and 3.9% for placebo. An analysis assuming everyone stayed on treatment gave bigger figures. Always check which analysis a headline quotes.
Why trials report two kinds of analysis
A treatment-policy analysis measures the effect of being assigned to treatment. It includes the real-world fact that some people stop or have other events, as the analysis defines them. A trial-product or continued-treatment analysis estimates what happens when everyone takes the treatment as intended.
Do not swap one for the other without saying so. Setting a continued-treatment figure for one medicine against a treatment-policy figure for another inflates the gap. Methods for missing data, how well people stuck to treatment and any extra care allowed also shape the published numbers.
Comparing separate trials misleads
Separate trials may recruit people with different starting weights, diabetes status, ages or health conditions. They may offer different behavioural support and run for different lengths of time. A bigger loss in one trial does not on its own prove one medicine beats another.
Head-to-head randomised trials give a stronger direct comparison. Even then, the result applies to the doses and people studied. The trial cannot tell you which treatment you will tolerate best, which you can afford or which suits your health goal.
Use the evidence in your own review
Track percentage change from a reliable starting weight. Kilograms alone, or comparisons with friends, tell you less. For weight management, current UK prescribing information calls for an individual decision on carrying on if you have not lost at least 5% of your starting weight after six months, weighing benefits and risks.
Review your eating, daily function, symptoms and how well you stick to treatment alongside the number on the scales. Early results while you step up the dose do not compare with a finished 68-week trial. Good use of evidence turns averages into realistic expectations and review points. A research result is never a guarantee.
Sources
Your own medicine leaflet and prescriber come first. A source from another country does not mean the same rule applies in the UK.
- Wegovy FlexTouch UK prescribing information medicines.org.uk
- STEP 1 randomised trial pubmed.ncbi.nlm.nih.gov
- STEP 5: two-year semaglutide trial pubmed.ncbi.nlm.nih.gov
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