Do GLP-1 drugs like semaglutide protect the heart even in people without diabetes?

Strongest form. The strongest version of the proposition is: In adults with overweight/obesity and established cardiovascular disease but no diabetes, semaglutide causes a clinically meaningful reduction in major adverse cardiovascular events independent of weight loss alone. The relevant question is whether the cited evidence establishes that specific claim.

SELECT strongly supports the cardiovascular-benefit part of the statement: randomization to weekly subcutaneous semaglutide 2.4 mg reduced major adverse cardiovascular events in adults with overweight or obesity, established cardiovascular disease, and no diabetes. The reported event proportions were 6.5% versus 8.0%, with hazard ratio 0.80. However, randomization identifies the total treatment effect, not which fraction operates independently of weight loss. A September 2026 SELECT mediation analysis estimated body-weight mediation at 19.5%, but its confidence interval was very wide, spanning -33.0% to 110.7%; waist circumference and other candidate mediators also had broad uncertainty. These analyses support plausible additional pathways but do not uniquely establish a weight-independent causal effect. Therefore the clinical benefit is well supported, while the stronger mechanistic clause remains uncertain. Findings should not automatically be extended to oral formulations, every GLP-1 drug, or people without established cardiovascular disease.