What happened
Researchers at Penn Medicine tracked more than 110,000 women aged 45 to 80 and found that those taking GLP-1 drugs, the class behind Ozempic, Wegovy, Mounjaro, and Zepbound, were about 30% less likely to develop breast cancer. In a tightly matched analysis of 30,528 women, paired on age, BMI, breast density, and diabetes status, the reduction held at 30.5%. The findings were presented at the 2026 ASCO Annual Meeting and published in JCO Oncology Practice.
Why this matters: current options to lower breast cancer risk are thin. Tamoxifen works but many women decline it over side effects, and preventive surgery is a drastic step. GLP-1 drugs are already taken by millions, and they touch many pathways tied to cancer, weight, inflammation, metabolism, even gene activity. Lead author Dr. Elizabeth McDonald is careful here: this is observational, not proof, which is why a multisite prevention trial is now being planned.
Observational data cannot confirm cause, and weight loss alone may explain part of the signal. But a medication millions already take quietly lowering cancer risk is exactly the kind of lead worth a real trial. If a drug you took for metabolism also cut your cancer risk, how much would that change the conversation with your doctor?
Source
Reported by Ozempic and similar weight-loss drugs linked to 30% lower breast cancer risk via sciencedaily.com, published June 6, 2026.