STEP Trials
The clinical trial program behind Wegovy — STEP 1 showed 14.9% average weight loss with weekly semaglutide 2.4 mg.
STEP (Semaglutide Treatment Effect in People with Obesity) is the trial program that earned Wegovy its approval. STEP 1, published in the New England Journal of Medicine in 2021, randomized 1,961 adults with obesity or overweight plus a comorbidity to weekly semaglutide 2.4 mg or placebo for 68 weeks alongside lifestyle counseling: the drug arm averaged 14.9% body-weight loss versus 2.4% on placebo, with about a third losing 20% or more.
Later STEP trials extended the picture — maintenance after loss, patients with diabetes (smaller averages, a consistent finding), adolescents, and head-to-head context. When a Wegovy page cites "about 15%," STEP 1 is the receipt; knowing the trial's name lets you check any marketing claim against the primary source.
This glossary entry is general information, not medical advice, and is written to be consistent with FDA prescribing information and primary trial publications as of its last review. Always consult a licensed healthcare provider for personal medical decisions.
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