Popular Weight Loss Drugs Linked to Lower Risk of Breast Cancer

The potential benefits of GLP-1 drugs, like Ozempic or Wegovy, are stacking up.

These novel medications were originally designed to treat diabetes, and now, millions more use the injections to help with weight loss.

But the perks may extend far beyond the metabolism.

As GLP-1s like semaglutide and liraglutide explode in popularity, scientists are noticing a striking pattern:

People taking these drugs tend to have lower rates of disease, such as brain disease, kidney disease, heart disease, liver disease, and even cancer.

Now, three new observational studies suggest there are perks for breast cancer, specifically.

Their results suggest that not only do people who take GLP-1 medications have 30 percent lower odds of developing breast cancer, but those who are diagnosed are also half as likely to see their breast cancer spread and 6 percent less likely to die of the disease.

These hopeful outcomes were shared ahead of publication at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

The results of the first study were presented by Elizabeth McDonald, a practicing breast radiologist at the University of Pennsylvania.

She and her team considered health data from more than 110,000 women aged 45 to 80 with a BMI of 25 or higher (considered the “overweight” threshold).

Of the women enrolled between 2022 and 2025, nearly 14 percent had documented prescriptions for GLP-1 medication.

The study did not account for how long participants used GLP-1 drugs; however, it found that anyone who had taken the drugs was 30.5 percent less likely to be diagnosed with breast cancer.

This was true even when accounting for age, race, ethnicity, BMI, breast density, and diabetes status.

“Our study was observational and does not definitively confirm an association between GLP-1 medications and reduced breast cancer incidence,” explains McDonald.

“It does add to the growing body of evidence suggesting that it’s worth investigating these weight loss drugs as potential cancer prevention tools.”

McDonald and her collaborators are now working on a clinical trial to test whether these drugs can lower breast cancer incidence in women who are at high risk.

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“GLP-1 medications are intriguing from a cancer research perspective because they weren’t designed for cancer therapy, but they do affect many different targets and pathways associated with cancer development, so we’re eager to study them in this context,” says McDonald.

Another recent study, presented at the same conference, also supports future investigations into breast cancer and GLP-1 drugs.

Among more than 12,000 people with lung, breast, colorectal, or liver cancer, those who took GLP-1’s in the analysis showed a significantly lower risk of spread, compared with people taking a different diabetes medication.

For breast cancer, progression to a more advanced stage occurred in 10 percent of patients taking GLP-1 drugs, compared with 20 percent of those on another diabetes drug.

“Our study found that use of GLP-1 drugs… was associated with a meaningful reduction in cancer progression across 4 solid tumor types,” says lead study author Mark David Orland, an oncologist from the Taussig Cancer Institute at Cleveland Clinic.

“It provides early evidence that future studies are worth pursuing.”

The third study on breast cancer presented at ASCO’s annual conference further underscores this pursuit.

It found that among 137,493 breast cancer patients, those treated with GLP-1 drugs for at least three continuous months had a 6 percent higher overall survival rate at five years.

The authors conclude that future studies are warranted to determine whether this association is driven by a biological mechanism.

Related: Weight Loss on GLP-1 Drugs Linked to Lower Risk of Disease, Study Finds

GLP-1 drugs are designed to mimic natural hormones in the body, which suppress appetite and promote weight loss. But emerging research suggests that’s just the tip of the iceberg. These drugs also seem to impact inflammation and immune function.

So while obesity is linked to worse outcomes in patients with breast cancer, weight loss may not be the only way that GLP-1 drugs are lowering risk.

“GLP-1 receptor agonists have never been just glucose-lowering drugs,” says Marcin Chwistek, an oncologist at Fox Chase Cancer Center and an ASCO Expert in supportive care.

“Their anti-inflammatory and immune-modulatory properties have long suggested broader effects. What’s new here is the consistency across tumor types, and data this large and this consistent warrant a prospective randomized trial.”

This year, estimates predict more than 320,000 women in the US will be diagnosed with breast cancer, and about 40,000 will die of the disease.

If we are lucky, we may already have a medication on hand that can improve those rates.

All three paper findings were shared at the American Society of Clinical Oncology’s annual meeting in Chicago.