Weight outcomes
STEP 1 (n=1,961, 68 weeks): mean weight reduction of 14.9% with 2.4 mg weekly versus 2.4% with placebo; 86% of participants lost at least 5%. STEP 4 showed weight was largely maintained with continued treatment versus rebound after switch to placebo.
Glycemic outcomes
In the SUSTAIN program in type 2 diabetes, semaglutide reduced HbA1c by roughly 1.5–1.8 percentage points across doses, outperforming comparators in head-to-head trials.
Cardiovascular and renal outcomes
SUSTAIN-6 reported a reduction in major adverse cardiovascular events in patients with type 2 diabetes at high CV risk; the SELECT trial subsequently reported cardiovascular benefit in people with overweight/obesity and established cardiovascular disease without diabetes.
The honest caveat
These are medication effects under trial conditions with structured titration and follow-up. Real-world adherence, tolerability, and persistence vary — and benefit requires continuing treatment, as discontinuation trials show substantial regain.
References
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med 2021. [source]
- Drucker DJ. Mechanisms of Action and Therapeutic Application of Glucagon-Like Peptide-1. Cell Metab 2018. [source]
- ClinicalTrials.gov — registered semaglutide studies. [source]
Evidence tier: Approved medicine · Last reviewed: 2026-09-05 · Sources cited below.