Ask most people what a GLP-1 does and they'll say weight loss or blood sugar. But some of these drugs have now cleared a much higher bar — proving in dedicated trials that they cut heart attacks, strokes, and cardiovascular death. Here's what the evidence actually shows, and why it matters well beyond the scale.
More than a weight-loss or diabetes drug
Most conversations about GLP-1 medications focus on weight loss or blood sugar control, but a growing body of large-scale clinical trial evidence shows several of these drugs directly reduce cardiovascular events — heart attacks, strokes, and cardiovascular death — independent of, and in addition to, their effects on weight. This is a meaningfully different, higher bar of evidence than "helps you lose weight, which is generally good for your heart" — these are dedicated cardiovascular outcomes trials designed specifically to test that question directly.
The landmark trials
LEADER (liraglutide). According to PubMed, this trial randomized 9,340 patients with type 2 diabetes and high cardiovascular risk to liraglutide or placebo. Liraglutide significantly reduced the primary composite outcome of cardiovascular death, non-fatal heart attack, or non-fatal stroke (13.0% vs. 14.9% with placebo), reduced cardiovascular death specifically (4.7% vs. 6.0%), and reduced death from any cause (8.2% vs. 9.6%) over a median follow-up of 3.8 years (Marso et al., New England Journal of Medicine, 2016, DOI (external link)). This was one of the first trials to establish that a GLP-1 medication could directly reduce cardiovascular events, not just improve risk factors like blood sugar.
SELECT (semaglutide). This trial extended the question to a different population: people with overweight or obesity and established cardiovascular disease, but without diabetes — testing whether the cardiovascular benefit held even outside a diabetes population. The main SELECT trial reported a 20% reduction in major adverse cardiovascular events with semaglutide compared to placebo in this population (Lincoff et al., , 2023, ). A related substudy publication found semaglutide also improved kidney outcomes — a lower rate of significant kidney function decline and kidney disease progression — suggesting the cardiovascular benefit is part of a broader cardio-metabolic-kidney effect, not an isolated finding (Colhoun et al., , 2024, ).