Ozempic and Wegovy Semaglutide May Protect Heart Health Beyond Weight Loss

Semaglutide, the medicine used in Ozempic and Wegovy, may offer important heart-health benefits. It could lower the likelihood of stroke or cardiac arrest, including for people who do not lose weight.

The SELECT trial and cardiovascular outcomes

The evidence comes from the Semaglutide and Cardiovascular Outcomes (SELECT) trial, the biggest and longest clinical study of semaglutide in people without diabetes. Funded by drug manufacturer Novo Nordisk, this major trial included approximately 17,600 adults who were overweight or obese, had existing cardiovascular disease, and did not have diabetes.

Last year, researchers used the trial data to show that weekly semaglutide injections taken for more than three years could cut the average risk of stroke, heart attack or fatal cardiovascular events by almost 20 percent.

A new team led by University College London cardiologist John Deanfield has now found that these benefits are seen irrespective of weight loss.

Between 2018 and 2023, participants' chances of a serious cardiovascular event, such as a heart attack or stroke, declined by broadly the same amount regardless of their weight at the start of the trial or how much weight they lost while taking semaglutide. SELECT participants were aged 45 and above, and almost three-quarters were male.

Semaglutide benefits beyond weight loss

Although semaglutide is now well known for suppressing appetite and causing rapid weight loss, it was first developed as a diabetes treatment. Clinical trials have demonstrated that semaglutide injections can reduce negative cardiovascular outcomes in people with diabetes, but the advantages for patients without insulin problems have been less certain.

Some researchers have proposed that it is semaglutide's treatment of obesity that enhances cardiovascular health, although the drug could provide additional benefits.

In a recent Nature Medicine analysis of the SELECT trial, biomedical researcher Donna Ryan and colleagues, including Deanfield, identified lasting weight loss of 10 percent on average over four years in people of every sex, race, age and body size.

"This degree of weight loss in such a large and diverse population suggests that it may be possible to impact the public health burden of multiple obesity-related illnesses," says Ryan, of the Pennington Biomedical Research Center in the US.

"While our trial focused on cardiovascular events, many other chronic diseases including several types of cancer, osteoarthritis, and anxiety and depression would benefit from effective weight management."

Questions over Ozempic and heart health

However, as Deanfield, Ryan and their co-authors note in their latest analysis, semaglutide's health gains may not all arise from treating obesity. An as-yet unknown mechanism may be involved, extending beyond reduced body fat.

Deanfield presented the new results at the European Congress on Obesity (ECO) earlier in May, where Ryan also presented findings. Taken together, the two studies are likely to fuel further discussion.

Earlier research indicates that, after patients stop semaglutide injections, they generally regain roughly two-thirds of the weight lost within a year. The long-term weight-loss benefits require more investigation, as do the effects on cardiovascular risk after semaglutide injections are discontinued.

Scientists unconnected with either new study have also warned against prescribing semaglutide to large sections of the population before more is known about the way the medicine works.

Further research into Ozempic's unexpected effects on heart health could reshape scientists' understanding of obesity and cardiovascular disease.

Ryan's study has been published in Nature Medicine. Deanfield's analysis was presented at ECO before peer review.