Written by Douglas Feil, NBCF Chief Program Officer
The information provided in this article is for educational and informational purposes only and is not intended to provide medical advice, diagnosis, or treatment. Every person’s health and breast cancer experience is different. If you have questions about GLP-1 medications, breast cancer risk, recurrence, or treatment, talk with your healthcare provider or oncology team. Do not start, stop, or change any medication without first consulting your health care provider.
Over the last several years, GLP-1 medications have become increasingly common for treating certain conditions, such as type 2 diabetes and obesity. As GLP-1 use grows, people with breast cancer and those concerned about their breast cancer risk may have questions about whether these medications affect cancer risk, recurrence, or treatment.
With so much information in the news and online about GLP-1 medications and breast cancer, it can be hard to know what’s accurate—and what’s not. Below are frequently asked questions about GLP-1 medications and their connection with breast cancer.
Research into GLP-1 medications and how they affect breast cancer is new and still ongoing. At this time, long-term data on GLP-1 medications’ outcomes on breast cancer risk, recurrence, and side effects are still developing. Because research is still emerging, it is important to carefully discuss GLP-1 medication use with your healthcare provider or oncology team, and how it may affect your personal health.
Throughout the day, your body naturally produces a hormone called glucagon-like peptide-1 (GLP-1). This natural hormone helps regulate your blood sugar and tells your brain and digestive system that you’re full after eating.
GLP-1 medications are prescription drugs that mimic the effects of the naturally occurring GLP-1 hormone in the body. The synthetic (non-natural) medication binds to the same receptors as the natural GLP-1 hormone, creating similar effects of lowering blood sugar and helping the body know when it’s full (reducing appetite).
Examples of GLP-1 medications include:
At this time, current research has not shown that GLP-1 medications increase the risk of developing breast cancer. Some research has even found an association between GLP-1 use and lower breast cancer incidence rates. A possible explanation for this association is that GLP-1 medications typically help reduce body weight and obesity. Because obesity is a known risk factor for breast cancer, weight loss through GLP-1 medications may help lower breast cancer incidence.
A 2026 study conducted by researchers at Penn Medicine analyzed the health records of 111,646 women between the ages of 45 and 80 who were either overweight or obese, and who had undergone breast imaging. After accounting for differences between the groups (matched analysis), women with documented GLP-1 prescriptions had approximately 30% lower odds of a new breast cancer diagnosis than women who did not have documented GLP-1 use.
However, the study was observational, meaning it analyzed existing health records rather than conducting its own trial that randomly assigned people to receive GLP-1 medications. While the study found an association between GLP-1 use and lower breast cancer incidence, it cannot establish that GLP-1 medications cause the lower incidence.
The findings do not establish that GLP-1 medications prevent breast cancer. More clinical trials are needed to determine whether GLP-1 medications could play a role in breast cancer prevention. [2]
Early research suggests the GLP-1 medications may be associated with improved outcomes for some breast cancer survivors, but their effect on breast cancer recurrence is not yet established.
A 2026 study published in JAMA Network Open examined more than 841,000 people diagnosed with Stage 1-3 breast cancer and found associations between GLP-1 use and improved overall survival and recurrence-free survival. However, the study was observational, so the findings do not establish that GLP-1 medications reduce breast cancer recurrence or improve survival.
More research and clinical studies are needed to determine if GLP-1 medications play a role in preventing breast cancer recurrence. [3]
Research on using GLP-1 medications during breast cancer treatment is still limited. There is currently no evidence establishing that GLP-1 medications reduce the effectiveness of standard breast cancer treatments, but potential interactions and side effects are being studied.
It’s important to note that GLP-1 medications can cause certain side effects, such as nausea, vomiting, diarrhea, constipation, and decreased appetite. These may overlap with some side effects of breast cancer treatment, particularly chemotherapy. This may make it difficult for some patients to maintain adequate nutrition and hydration and to feel well during treatment.
Additionally, GLP-1 medications also slow gastric emptying (the process of food moving from your stomach into your small intestine), which may affect the absorption of some oral medications. Researchers are studying whether these effects have implications for specific breast cancer treatments.
If you are receiving chemotherapy, hormone therapy, radiation, immunotherapy, or targeted therapy for breast cancer, talk with your care team before starting or stopping a GLP-1 medication. They will consider your specific case and treatment, other medications, nutritional needs, and potential side effects before making a recommendation.
If you have breast cancer, are a breast cancer survivor, or have concerns about your breast cancer risk, talk with your healthcare team or provider before starting a GLP-1 medication.
Your oncologist can help you understand whether GLP-1 medication use may be appropriate during or after your breast cancer treatment. Likewise, your primary care provider or endocrinologist can also help evaluate your overall health, medical history, current medical conditions, and treatment goals.
[1] Williams S. GLP-1s 101: What the Science Says About Weight Loss, Side Effects, Safety. Stanford Medicine. June 29, 2026.
[2] Penn Medicine. GLP-1 use linked to lower breast cancer incidence in large cohort study. June 2, 2026.
[3] Tatum KL, et al. Survival and Recurrence With GLP-1 Receptor Agonists in Breast Cancer. JAMA Network Open. 2026;9(5):e2612133.
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