GLP-1 Weight Loss Drugs Linked to 30% Lower Breast Cancer Risk in Major Study
Research involving over 110,000 women found those taking Ozempic, Wegovy, and similar medications had significantly reduced cancer rates, though clinical trials are still needed.
Popular weight-loss medications including Ozempic, Wegovy, Mounjaro, and Zepbound may offer an unexpected benefit beyond helping people manage weight and diabetes. A large-scale study involving more than 110,000 women found that those taking GLP-1 drugs were approximately 30% less likely to develop breast cancer compared to women not using these medications.
The findings were presented at the 2026 American Society of Clinical Oncology Annual Meeting and published in JCO Oncology Practice. Dr. Elizabeth McDonald, a professor of Radiology at the University of Pennsylvania Perelman School of Medicine, emphasized that while the observational study does not definitively confirm a direct association, it adds to growing evidence suggesting these medications may have cancer prevention potential.
GLP-1 medications work by mimicking a naturally occurring hormone called glucagon-like peptide-1, which helps regulate appetite and blood sugar levels. The drug class includes semaglutide medications like Ozempic and Wegovy, as well as tirzepatide drugs such as Mounjaro and Zepbound. Originally developed for type 2 diabetes treatment, these drugs have become some of the most widely prescribed weight-loss medications in the United States.
The research team reviewed electronic health records from 111,646 women between ages 45 and 80 who had a body mass index of 25 or higher and underwent breast imaging within the Penn Medicine health system between January 2022 and June 2025. Among these women, 15,264 had documented prescriptions for GLP-1 medications, representing 13.7 percent of the study population.
Dr. McDonald noted that GLP-1 medications are particularly intriguing from a cancer research perspective because they affect many different targets and pathways associated with cancer development, despite not being designed for cancer therapy. The research team is now working to launch a multisite clinical trial examining whether GLP-1 medications can lower breast cancer incidence in women considered high risk, including those with a previous history of breast cancer.
