Are the weight loss GLP-1 drugs also capable of reducing breast cancer risk? Research says it’s possible.
A large study involving more than 110,000 women found that those taking GLP-1 medications were significantly less likely to develop breast cancer than women who were not using the drugs.
The findings were presented at the 2026 American Society of Clinical Oncology Annual Meeting and published in JCO Oncology Practice.
Researchers reported that women using GLP-1 medications had about a 30% lower likelihood of being diagnosed with breast cancer.
The results are attention-getting, but researchers say that the study doesn’t actually prove GLP-1 drugs directly prevent breast cancer or cut the risk.
Because the research was observational, it can only show an association between medication use and cancer risk. Cause-and-effect was not established.
Still, the findings can’t be kicked aside. They suggest that GLP-1 drugs may affect biological processes involved in cancer development.
There will be more investigation into these findings.
What Are GLP-1 Medications?
GLP-1 drugs mimic a naturally occurring hormone called glucagon-like peptide-1, which helps regulate appetite, blood sugar levels and insulin release.
This class of drugs does NOT increase metabolism or rev up fat burning.
So when one loses weight on Ozempic, Wegovy or Zepbound, it’s due to eating less via the reduced appetite and blunted “food noise” that the drugs bring on.
Their growing popularity has attracted the attention of cancer researchers.
Study Examined More Than 111,000 Women
Researchers reviewed electronic health records from 111,646 women between 45 and 80 who had a body mass index of 25 or higher and underwent breast imaging within the Penn Medicine health system between 2022 and 2025.
More than 15,000 women had been prescribed a GLP-1 medication, while around 96,000 had not used the drugs.
To strengthen the analysis, researchers also created a matched comparison group that paired GLP-1 users with nonusers who had similar characteristics, including age, BMI, race, ethnicity, breast density and diabetes status.
The results remained consistent across both analyses.
Lower Breast Cancer Rates Among GLP-1 Users
In the overall study population, women taking GLP-1 medications had 35.1% lower odds of developing breast cancer.
In the matched comparison group, they had 30.5% lower odds.
Though this is an observational result, researchers are taking it very seriously.
They propose that the association could be explained by the weight loss from a GLP-1.
Obesity is a well-established risk factor for breast cancer, especially after menopause.
Researchers also believe other biological mechanisms may be involved.
GLP-1 drugs can reduce chronic inflammation, which has long been linked to cancer development.
They also influence metabolism and may affect epigenetic processes that regulate gene activity.
Scientists suspect these combined effects could help create an environment that is less favorable for cancer growth.
Could GLP-1 Drugs Help Prevent Breast Cancer?
The study authors are eager to investigate if these drugs might possibly have a preventive effect on breast cancer development.
However, they are not yet recommending these drugs as part of any breast cancer prevention regimen.
Future clinical trials are in the works.
