Does Semaglutide Cut Heart Attack Risk?

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For years, semaglutide was understood first as a blood-sugar drug, and then as a weight-loss drug. A series of large cardiovascular trials has reframed it again — as a drug that measurably reduces heart attacks, strokes and cardiovascular deaths. That reframing matters, because heart disease is, in the end, much of what obesity and type 2 diabetes threaten people with. This guide covers what those trials — SELECT, SOUL, and the studies that came before them — actually showed about semaglutide and cardiovascular outcomes, and, just as importantly, where the honest limits of that evidence lie.

Why Cardiovascular Trials Matter

It is worth being clear, first, about what a cardiovascular outcomes trial is and why it carries so much weight.

A drug can lower blood sugar, or shrink waistlines, without anyone yet knowing whether it prevents the things people actually fear — a heart attack, a stroke, an early death. Those are different questions. Improving a number on a lab report is a surrogate; preventing a heart attack is the outcome that matters. A cardiovascular outcomes trial is built to answer the second question directly. It enrolls thousands of people, follows them for years, and counts hard events — grouped, in most trials, into a composite called MACE: major adverse cardiovascular events, typically cardiovascular death, non-fatal heart attack and non-fatal stroke.

These trials are large, slow and expensive, and for good reason regulators treat them as the gold standard. When a drug is said to have a proven cardiovascular benefit, it means a trial of this kind has shown it. Semaglutide has several.

SUSTAIN-6: The First Signal

The story starts in 2016, with a trial called SUSTAIN-6.

SUSTAIN-6 tested injectable semaglutide in people with type 2 diabetes who were at high cardiovascular risk, following them over about two years. The result was a roughly 26% reduction in MACE compared with placebo. It established injectable semaglutide as a drug that reduces major cardiovascular events in people with diabetes and established heart disease — one of an early wave of trials, around 2016, showing this benefit across the GLP-1 receptor agonist class.

That finding, supported by further data, is why injectable semaglutide — sold for diabetes as Ozempic — carries a cardiovascular indication on its label: it is approved not only to lower blood sugar but to reduce cardiovascular risk in adults with type 2 diabetes and known heart disease. SUSTAIN-6 was the first signal. The trial that made the wider world pay attention came later.

SELECT: The Landmark Trial

SELECT is the trial that changed how semaglutide is understood.

Published in 2023, it was enormous — 17,604 adults across 41 countries — and its population was the key. Participants had overweight or obesity and established cardiovascular disease, but they did not have diabetes. That design was deliberate. Every earlier cardiovascular trial of semaglutide had been in people with diabetes, which made it impossible to fully separate the drug’s heart benefits from its blood-sugar effects. SELECT removed diabetes from the equation.

The result: semaglutide 2.4 mg — the dose sold as Wegovy — reduced MACE by about 20% compared with placebo, on top of standard cardiovascular care. All three components of the composite — cardiovascular death, heart attack and stroke — moved in the same direction. On the strength of this, Wegovy received a cardiovascular indication in 2024, approved to reduce the risk of cardiovascular death, heart attack and stroke in adults with cardiovascular disease and obesity or overweight.

SELECT also offered a clue about how semaglutide does this. A prespecified analysis estimated that only around a third of the cardiovascular benefit could be explained by the reduction in waist circumference — and the benefit began to appear early, within the first months, before participants had lost much weight. The implication is that semaglutide’s cardiovascular protection is not simply a downstream effect of slimming; the drug appears to act on the cardiovascular system more directly, through mechanisms still being worked out — thought to include anti-inflammatory effects, modest improvements in blood pressure and cholesterol, and direct actions on the blood vessels themselves. That has led some researchers to describe semaglutide less as a weight or glucose drug and more as a disease-modifying cardiovascular treatment.

SOUL: Extending the Evidence to the Pill

The most recent chapter, SOUL, addressed a practical gap: every cardiovascular result so far had come from injectable semaglutide. What about the pill?

SOUL tested oral semaglutide — the 14 mg daily tablet — in people with type 2 diabetes who also had established cardiovascular disease, chronic kidney disease, or both. Reported in 2025, it found a statistically significant reduction in MACE of about 14%. An earlier, smaller trial of the oral form, PIONEER 6, had already established its cardiovascular safety; SOUL was large enough to demonstrate benefit.

Alongside these sits FLOW, a trial in people with type 2 diabetes and chronic kidney disease, which found semaglutide reduced kidney-related and cardiovascular events. A separate trial program, STEP-HFpEF, found that semaglutide also improved symptoms and physical function in people with obesity-related heart failure with preserved ejection fraction — a common and hard-to-treat form of heart failure. Taken together, the trials describe a consistent picture across formulations and conditions: injectable and oral, in diabetes and in obesity, semaglutide reduces cardiovascular events. Our guide to oral semaglutide covers the tablet in more detail.

It is worth noting that this completed body of cardiovascular outcomes evidence is something semaglutide currently has and tirzepatide does not yet — tirzepatide’s dedicated cardiovascular outcomes trial in obesity is still ongoing, as our look at the tirzepatide trials describes.

How Big Is the Benefit, Really?

A 20% reduction sounds dramatic, and it is a real result — but the number needs reading carefully.

Reductions like “20%” or “26%” are relative. They describe how much the risk shrank, not how large the risk was to begin with. In SELECT, for instance, the rate of major cardiovascular events over the roughly three-year trial was in the region of 6 to 8% — so a 20% relative reduction translates to an absolute difference of roughly one and a half percentage points between the semaglutide and placebo groups. Put another way, a substantial number of people had to be treated for several years for one cardiovascular event to be prevented.

That is not a criticism of the drug — it is simply what cardiovascular prevention looks like. Most preventive cardiovascular therapies, including widely used and valuable ones, produce relative reductions in roughly this range, and at the scale of a population, preventing one event among several dozen treated people is genuinely worthwhile. But for an individual weighing whether the cardiovascular benefit alone justifies treatment, the honest figure is the absolute one: a modest, real reduction in risk — not a guarantee, and not a transformation.

Who the Evidence Applies To

There is one more distinction that matters, and it is easy to lose.

The cardiovascular trials studied specific populations. SUSTAIN-6 and SOUL enrolled people with type 2 diabetes. SELECT enrolled people who had established cardiovascular disease — a prior heart attack, stroke, or peripheral artery disease — along with obesity. In all of these trials, the participants were, by design, at high cardiovascular risk to begin with.

That is exactly the group in whom the benefit has been demonstrated — and it is a large and important group. But it is not everyone who takes semaglutide. The evidence does not establish that a metabolically healthy person, with no diabetes and no cardiovascular disease, taking semaglutide for relatively modest weight loss, gains a meaningful reduction in cardiovascular events. They may; it simply has not been shown, because that is not who the trials enrolled. The proven cardiovascular benefit of semaglutide belongs to people at elevated cardiovascular risk. Stretching it into a general promise of heart protection for everyone goes beyond what the trials support.

Frequently Asked Questions

Does semaglutide reduce the risk of heart attack and stroke?

Yes, in the populations studied. Large trials — SUSTAIN-6, SELECT and SOUL — have shown semaglutide reduces major adverse cardiovascular events, a composite of cardiovascular death, heart attack and stroke, by roughly 14 to 26% depending on the trial and population.

What was the SELECT trial?

SELECT was a landmark trial of 17,604 adults with overweight or obesity and established cardiovascular disease, but without diabetes. It found that semaglutide 2.4 mg reduced major cardiovascular events by about 20%, and it led to Wegovy’s cardiovascular indication in 2024.

Does the cardiovascular benefit come only from weight loss?

Apparently not entirely. A prespecified SELECT analysis estimated that only about a third of the benefit was explained by waist-circumference reduction, and the benefit appeared early, before much weight was lost — suggesting semaglutide acts on the cardiovascular system more directly.

Does oral semaglutide also have a cardiovascular benefit?

Yes. The SOUL trial, reported in 2025, found oral semaglutide reduced major cardiovascular events by about 14% in people with type 2 diabetes and established cardiovascular or kidney disease.

If I take semaglutide just for weight loss, will it protect my heart?

The cardiovascular benefit has been proven in people at high cardiovascular risk — those with established heart disease or diabetes. It has not been demonstrated for a person without those conditions taking semaglutide for modest weight loss. The benefit is real for the studied groups, but should not be assumed for everyone.

Does semaglutide help with heart failure?

For one form of it, yes. The STEP-HFpEF trial program found that semaglutide 2.4 mg improved symptoms, physical limitations and exercise capacity in people with obesity-related heart failure with preserved ejection fraction. This is distinct from the heart-attack and stroke reduction seen in SELECT, and reflects a separate part of the cardiovascular evidence.

The Bottom Line

The cardiovascular trials have done something unusual: they have turned a drug developed for blood sugar, and popularized for weight loss, into a proven cardiovascular medicine. SUSTAIN-6 showed the signal, SELECT proved the benefit in people without diabetes, and SOUL extended it to the oral form. Across the program, semaglutide reduces heart attacks, strokes and cardiovascular deaths in the people studied — and appears to do so partly through mechanisms beyond weight loss.

The honest reading holds two truths together. This is a genuine, well-evidenced benefit, and a meaningful one at the scale of a population. At the same time, the relative reductions translate into more modest absolute ones, and the benefit is proven for people at elevated cardiovascular risk — not established as a universal heart-protection guarantee. For anyone whose decision involves cardiovascular risk specifically, that distinction is the one worth discussing with a doctor.

This article is general information, not medical advice. Trial figures reflect published results as of May 2026; cardiovascular treatment decisions should be made with a qualified healthcare provider.