GLP-1 and Cardiovascular Risk: The SELECT Trial Evidence

Most of the GLP-1 conversation is about the scale. The SELECT trial was built to answer a different question entirely: does losing weight on semaglutide actually prevent heart attacks and strokes, in people who don't have diabetes, measured against hard cardiovascular endpoints rather than a surrogate marker? It's one of the largest cardiovascular outcomes trials ever run in this drug class, and it changed Wegovy's FDA label.

The trial

SELECT (Semaglutide Effects on Heart Disease and Stroke in Patients with Overweight or Obesity) enrolled 17,604 adults 45 or older who already had established cardiovascular disease and a BMI of 27 or higher, but no history of diabetes — 8,803 randomized to semaglutide, 8,801 to placebo¹. The primary endpoint was a composite: death from cardiovascular causes, nonfatal heart attack, or nonfatal stroke, tracked over a mean follow-up of nearly 40 months¹. This population matters: these weren't people starting a GLP-1 purely for weight loss with no cardiac history — every participant already had documented cardiovascular disease, which is exactly the population where a heart-protective effect is hardest to demonstrate and most clinically consequential to find.

The results

The primary composite outcome occurred in 569 of 8,803 people (6.5%) on semaglutide versus 701 of 8,801 (8.0%) on placebo — a hazard ratio of 0.80 (95% CI, 0.72 to 0.90), meaning a 20% relative risk reduction, with a P-value under 0.001¹. That's not a borderline finding — it's a large, precisely-measured effect on hard endpoints (death, heart attack, stroke), not a proxy measure like blood pressure or cholesterol. As with other large GLP-1 trials, more people discontinued semaglutide than placebo due to adverse events (16.6% versus 8.2%)¹ — the same gastrointestinal tolerability trade-off covered in GLP-1 side effects: what the STEP and SURMOUNT trials actually reported, not a new safety signal specific to this trial.

Why this changed the label, not just the research conversation

A composite of cardiovascular death, heart attack, and stroke is about as "hard" a clinical endpoint as a trial can measure — exactly what regulators look for when deciding whether to expand an approved use. Wegovy's current FDA label now includes an indication "to reduce the risk of major adverse cardiovascular (CV) events (CV death, non-fatal myocardial infarction, or non-fatal stroke) in adults with established CV disease and either obesity or overweight"² — language pulled directly from what SELECT measured, and it applies to both the injection and the newer Wegovy tablet formulation². That's a materially different status than "an interesting finding in the literature": a prescriber can write Wegovy specifically for cardiovascular risk reduction, and that on-label indication can matter for insurance coverage conversations in a way an off-label rationale doesn't.

What this doesn't establish

SELECT enrolled people who already had established cardiovascular disease — it does not show that semaglutide prevents a first heart attack or stroke in someone with obesity but no existing cardiovascular diagnosis, and the trial excluded people with diabetes, so it doesn't speak to that population's cardiovascular risk reduction directly (a separate, older body of diabetes-specific cardiovascular trials exists for GLP-1s, but that's not what SELECT measured). It's also semaglutide-specific: SELECT did not test tirzepatide, and Zepbound's label does not carry the equivalent cardiovascular risk reduction indication as of this writing — see Wegovy vs Zepbound: what's actually different for how the two brands' approved uses have diverged more broadly.

Where this fits alongside GLP-1's other non-weight-loss trial evidence

Cardiovascular risk reduction joins a growing list of hard outcomes GLP-1 trials have demonstrated beyond the scale — kidney protection in the FLOW trial and sleep apnea improvement in SURMOUNT-OSA are two more; see GLP-1 and kidney disease: the FLOW trial evidence and GLP-1 and sleep apnea: the SURMOUNT-OSA trial evidence for those. None of this changes the core safety profile and boxed warning you should discuss with a prescriber before starting — see GLP-1 boxed warnings: what the label actually says.

Where this fits your provider decision

If you have established cardiovascular disease alongside obesity or overweight, ask your prescriber directly whether they're aware of this specific indication and whether it changes how insurance frames your prior authorization — an on-label cardiovascular indication is a different conversation with a payer than a weight-loss-only request. Compare pricing across verified semaglutide programs on our semaglutide price board, and see how we weigh medical evidence in our Value Score methodology.

This piece sits in our research index alongside every other sourced explainer we publish — the trials, the compounding rules and the pricing mechanics, grouped by the question each one answers.