• Posted December 10, 2025

GLP-1 Medications Show Little Effect on Cancer, Study Shows

A new study suggests popular GLP-1 drugs, like Ozempic and Zepbound, may not lower cancer risk as some had hoped.

Researchers analyzed 48 randomized trials including 94,245 adults who were overweight, obese or had type 2 diabetes. More than 51,000 people took a GLP-1 drug, and nearly 43,000 received a placebo and were followed for about 70 weeks.

The team wanted to know whether these medications change someone’s risk of developing any of the 13 cancers linked to obesity. The results showed GLP-1 drugs had little to no effect on the risk of cancers such as breast, thyroid, pancreatic or kidney cancer.

“It’s not that GLP-1 does not reduce the risk of cancer; I don’t think we can make that conclusion from our study,” study co-author Dr. Cho-Han Chiang, a medical oncology fellow at Northwell Health Cancer Institute, told NBC News.

"I would say GLP-1 [drugs] probably do not increase the risk of cancer. It’s a little different," Chiang explained.

Earlier observational studies had suggested GLP-1 drugs might help prevent cancer, but those studies were based on existing patient data, not controlled trials, and may have included healthier patients with better access to care.

Several experts say longer research is still needed. Since many cancers grow slowly, tracking patients for only a year or two may not show the full picture.

Patients prescribed GLP-1s should be monitored for far longer, particularly for slow-growing diseases like breast and thyroid cancers, Dr. Kandace McGuire, a breast surgeon at Virginia Commonwealth University in Richmond who was not involved in the study, told NBC News.

The U.S. Food and Drug Administration (FDA) does, however, warn that folks with a personal or family history of a rare thyroid cancer should avoid certain GLP-1 drugs, Chiang said. But that warning is based on older studies done in rodents. Results of animal studies are often different in people.

Some experts say the findings are reassuring.

“This study gives us more reassurance about using these drugs in the treatment of things like obesity and type 2 diabetes,” Dr. Bassel El-Rayes, deputy director of the O’Neal Comprehensive Cancer Center at the University of Alabama at Birmingham, explained.

“There are questions left unanswered, like, Could it be protective against cancer? Could there be a small increase of risk that we’re not recognizing yet?” El-Rayes said.

What's more, doctors say most people are taking GLP-1 medications to manage weight, heart failure or sleep apnea, not to prevent cancer.

“Nobody comes to me and says, ‘I’d like to go on some medication to reduce my cancer risk,’ ” Dr. Susan Wolver, director of the Medical Weight Loss Program at VCU Health, told NBC News. 

Researchers say longer clinical trials will be needed before making any final conclusions about GLP-1 drugs and cancer.

More information

The Cleveland Clinic has more on GLP-1s.

SOURCE: NBC News, Dec. 8, 2025