Study: GLP-1 Drugs (like Mounjaro ) May Help Decrease Heart Attack Risk by 33%

Researchers analyzed real-world data from two large US insurance databases, following one group that started tirzepatide and another that started sitagliptin, an older diabetes drug chosen because it is not expected to raise or lower heart risk. Over one year, they tracked what doctors call MACE — major adverse cardiovascular events, a combined measure of heart attack, stroke, and death from any cause.

The gap between the two groups was clear. According to the study in The BMJ, the one-year risk of a major cardiovascular event was 2.9% among people taking tirzepatide, compared with 4.4% among those taking sitagliptin. That works out to roughly a 32% lower overall risk, and the researchers estimated that treating about 70 people with tirzepatide for a year would prevent one such event.

The most striking piece sits inside that composite. When the researchers looked at heart attacks on their own, tirzepatide was linked to a 33% lower risk. Strokes, by contrast, showed no meaningful difference between the two groups — so the overall benefit was driven by fewer heart attacks and fewer deaths, not by a drop in strokes.

This fits a broader pattern researchers have been tracing, in which GLP-1 drugs keep turning up benefits beyond weight loss.

This is the part that is easy to lose in a headline. Everyone in the study had both type 2 diabetes and established atherosclerotic cardiovascular disease — in other words, people already at high risk for a heart attack or stroke. They were all 40 or older. The results describe what happened in that specific group, and the researchers are careful to note that the findings may not extend to people without existing cardiovascular disease.

That matters because tirzepatide is far better known as a weight-loss and diabetes drug than as a heart medication. A 33% lower heart attack risk in a high-risk population is not the same as a 33% lower risk for a generally healthy person taking the drug to slim down. The study simply did not look at that group.

The Mounjaro, Zepbound, and Ozempic Question

It also helps to sort out the names, since they get tangled easily. Tirzepatide is the single active ingredient in both Mounjaro, approved for type 2 diabetes, and Zepbound, approved for weight loss — the same molecule sold under two brand names. It is not the same drug as semaglutide, the ingredient in Ozempic and Wegovy, though both belong to the broader family often labeled GLP-1 medications. Semaglutide has been studied for its own range of effects, including a possible link to lower depression and anxiety risk.

The study was designed to measure outcomes, not to pin down exactly how the drug works, so the mechanism remains an open question. Still, the researchers offered some informed thinking. Tirzepatide improves blood sugar control and reduces body weight, and it may also nudge blood pressure, cholesterol, and inflammation in helpful directions — each a known contributor to heart risk.

One detail stood out to the research team. The difference in cardiovascular events between the two groups began to appear early, before the point at which substantial weight loss would usually kick in. As lead author Nils Krüger, MD, MPH, of Brigham and Women's Hospital told Medical News Today, GLP-1–based medications were originally built to improve glucose control, but their effects appear to reach well beyond blood sugar and weight. That early separation hints that vascular or anti-inflammatory effects may be part of the picture, not weight loss alone.

There was also a surprising thread outside the heart. Tirzepatide was linked to fewer infections serious enough to require hospital admission and to lower infection-related deaths — a signal that the drug's reach may extend into pathways researchers are only beginning to map. Much of the everyday work of protecting arteries still comes down to familiar foundations, the kind covered in guidance on everyday foods that support clearer arteries.

For all the promising numbers, this was an observational study, which means it can show a strong association but cannot prove on its own that tirzepatide caused the lower risk. That distinction is the single most important thing to carry away from the coverage.

A few specific limits shape how far the findings stretch. The follow-up ran only about a year, with a median of under six months on treatment, so the study says nothing about whether the benefits hold up over the long haul. The comparison drug, sitagliptin, is a daily pill while tirzepatide is an injection, a difference that can influence who stays on treatment. And the authors acknowledge that unmeasured factors could partly explain the results, particularly the large drop in deaths from any cause.

Context on the drug's broad and fast-growing use — captured in the story of why so many people are starting these shots — is worth keeping in view too, since real-world enthusiasm often outpaces the long-term evidence.

Independent cardiologists who were not involved in the research read the results as an encouraging addition to a fast-moving field rather than a final word. Cheng-Han Chen, MD, an interventional cardiologist at MemorialCare Saddleback Medical Center, described a growing body of studies showing benefits across a spectrum of cardiometabolic conditions, and suggested these medications could play a meaningful role in lowering the overall burden of cardiovascular disease at a population level.

Others struck a more measured note about what comes next. Sanjeev Kumar Gulati, MD, of Baptist Health South Florida, said he would like to see longer-term and randomized studies to learn whether the cardiovascular benefits are sustained over many years, and whether they extend to people who do not already have established cardiovascular disease. The study was funded by the US National Institutes of Health and the German Heart Foundation, and the funders had no role in the design, analysis, or decision to publish.

For now, the takeaway is a hopeful but bounded one. In a group of people facing real cardiovascular risk, a drug many know only for weight loss was linked to fewer heart attacks — a finding worth watching as the longer, more definitive studies catch up. Alongside the medication conversation, the everyday groundwork of metabolic health stays part of the wider picture, including food-first ways to support GLP-1 activity and steadier blood sugar.