A new study found that women who take GLP-1 medications are about 30% less likely to develop breast cancer than women who do not use those drugs. The research, conducted at the University of Pennsylvania, focused on women who were overweight or obese and adds to a growing list of potential health benefits being studied for this class of medications.
According to Healthline, the study was presented at the 2026 American Society of Clinical Oncology Annual Meeting and published on June 2 in JCO Oncology Practice. The research team used electronic health records from the University of Pennsylvania Health System, which spans both academic and community medical sites across Pennsylvania and New Jersey.
The study identified 217,624 females who underwent breast imaging between January 1, 2022, and June 30, 2025. Researchers narrowed that group to 111,646 females between ages 45 and 80 who were overweight or obese, defined as having a BMI of 25 or higher, and who had documented breast imaging outcomes. Of those, 15,264, or about 13.7%, had been prescribed GLP-1 medications before their imaging exam. The remaining 86.3% had no record of GLP-1 use.
To reduce bias, researchers performed one-to-one matching. Each woman taking a GLP-1 drug was paired with a woman not taking one, matched on factors including age, race, ethnicity, BMI, breast density, and diabetes status. The goal was to isolate the effect of GLP-1 use from other variables that could independently affect breast cancer risk.
The results showed that women taking GLP-1 medications had about 35% lower odds of developing breast cancer in the full cohort. In the matched cohort, which controlled for those confounding factors, GLP-1 use was associated with a 30.5% reduction in breast cancer incidence.
GLP-1 medications work by mimicking a hormone called glucagon-like peptide-1, which helps regulate blood sugar and appetite. Semaglutide, the active ingredient in drugs like Ozempic and Wegovy, was originally developed to treat type 2 diabetes and is now widely prescribed for weight loss. Researchers believe the cancer risk reduction seen in the study may be related to the metabolic improvements these drugs produce, though the exact mechanism is not yet fully understood.
Scientists are also investigating GLP-1 drugs for use in other conditions beyond diabetes and obesity, including sleep apnea and addiction. The breast cancer findings add another dimension to that research, though experts say the drugs cannot yet be recommended specifically for cancer prevention. Regular screening and a healthy lifestyle remain the primary recommended preventive measures. More research is needed before clinical guidance changes.
The study's retrospective design means it drew on existing records rather than following patients through a controlled experiment. That limits the conclusions researchers can draw about cause and effect. Still, the size of the dataset and the careful matching process make the findings notable. Researchers are expected to continue investigating how GLP-1 medications affect cancer risk, particularly among women at higher risk due to weight or metabolic conditions.
