GLP-1 drugs like Ozempic or Zepbound may not affect risk of 13 obesity-related cancers

Popular weight-loss drugs “probably have little or no effect” on a person’s risk of developing one of the 13 obesity-related cancers, new research suggests.

Despite previous excitement around a potential link between GLP-1 drugs and a reduced risk of cancer, new research suggests the popular medications “probably have little or no effect” on a person’s risk of developing one of the 13 obesity-related cancers.

The findings, published Monday in the Annals of Internal Medicine, may seem counterintuitive, said co-author Dr. Cho-Han Chiang, who conducted the study earlier this year as an internal medicine resident at Mount Auburn Hospital, a Harvard Medical School teaching hospital in Cambridge, Massachusetts.

“GLP-1 can make people lose weight, and so, if obesity increases the risk of cancer, then, hypothetically speaking, losing weight through GLP-1 may actually reduce the risk of developing cancer,” said Chiang, now a medical oncology fellow at the Northwell Health Cancer Institute in New York. “That was the excitement in this whole research of GLP-1 and cancer risk.”

Accordingly, previous research had suggested the drugs — which include Ozempic and Zepbound — may help lower cancer risk. For example, a 2024 study published in the journal JAMA Network Open showed that people with Type 2 diabetes who took GLP-1s had significantly reduced risks of 10 obesity-related cancers. However, that study was observational, Chiang said, meaning it analyzed existing patient data rather than performed a clinical trial. The patients who took GLP-1s may have had access to better health care and a lower risk of cancer to begin with, he said.

Chiang and his colleagues, on the other hand, reviewed 48 randomized controlled trials with a combined 94,245 patients who had Type 2 diabetes, overweight or obesity. Of those, more than 51,000 took a GLP-1 medication, while nearly 43,000 took a placebo. Patients were observed for a median follow-up period of 70 weeks.