Real-world study compares Wegovy and tirzepatide on heart outcomes

Novo Nordisk published a real-world analysis on August 31, 2025, reporting that people with obesity and cardiovascular disease who used Wegovy had a 57% lower risk of heart attack, stroke or death compared with people who used tirzepatide ^[1]. The finding was announced as part of the company's ongoing published research on Wegovy, alongside other 2025 data on the drug's weight-loss and health effects ^[1].

The comparison was observational, meaning researchers looked at existing patient records rather than randomly assigning people to take one drug or the other ^[1]. Because of that design, the study cannot establish that Wegovy caused better outcomes than tirzepatide. People who end up on one medication versus another in real-world care often differ in ways researchers cannot fully measure or adjust for, such as other health conditions, insurance access, or how closely they were monitored. A randomized controlled trial, where treatment assignment is decided by chance, is considered the stronger method for proving cause and effect.

Wegovy already carries a separate, more established cardiovascular claim based on a large randomized trial. In the SELECT trial, semaglutide 2.4 mg reduced the risk of major adverse cardiovascular events by 20% in adults with overweight or obesity, a result presented in August 2023 and published in the New England Journal of Medicine in November 2023 ^[1]. That trial led the FDA to approve Wegovy in March 2024 specifically to reduce cardiovascular risk in adults with established cardiovascular disease and either obesity or overweight ^[1]. A further analysis of SELECT presented in May 2025 reported that the reduction in cardiovascular events appeared early, before patients had lost a clinically meaningful amount of weight ^[1].

Tirzepatide, sold as Mounjaro and Zepbound, does not currently have an FDA-approved cardiovascular risk-reduction indication based on the sources reviewed here. The sources do not describe a randomized head-to-head cardiovascular outcomes trial comparing semaglutide and tirzepatide directly, so it is not yet known how the two drugs would compare under trial conditions rather than in real-world use.

Why it matters for patients

For people with obesity and existing heart disease who are choosing between GLP-1 medications, cardiovascular risk is often a central concern. This new real-world study adds another data point suggesting a possible advantage for Wegovy, but the 57% figure should be read cautiously because of the study's observational design ^[1]. Patients and prescribers weighing this information alongside Wegovy's randomized-trial-based FDA approval for cardiovascular risk reduction may find the totality of evidence more informative than any single study ^[1].

It is not yet known from these sources whether tirzepatide would show similar or different cardiovascular results in a randomized trial designed to test that question directly. Readers should also note that this analysis was published by Novo Nordisk, the maker of Wegovy, which has a commercial interest in the comparison ^[1].

What happens next

The sources reviewed do not describe a planned randomized trial directly comparing semaglutide and tirzepatide for cardiovascular outcomes. Novo Nordisk has continued to release additional Wegovy data through 2025 and 2026, including further analyses on weight loss, liver health, and cardiovascular findings, but none of the listed items announce a head-to-head randomized cardiovascular trial against tirzepatide ^[1]. Until such a trial is conducted, comparisons between the two drugs on heart outcomes will likely remain based on observational data, which carries the inherent limitations described above.