GLP-1 weight-loss drugs may lower the risk of developing certain cancers and slow tumor progression in patients with existing tumors [1, 2, 3].

These findings suggest a potential shift in how medications like Ozempic, Wegovy, and Zepbound are used, moving beyond diabetes and obesity treatment into oncology. Because one in eight U.S. adults currently takes a GLP-1 drug [1], any proven cancer-preventative benefit would have a massive impact on public health.

Researchers presented the data in early June 2026 at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago [2, 4]. The studies indicate that the metabolic and hormonal effects of GLP-1 agonists may interfere with the pathways that drive tumor growth [1, 5].

"Weight‑loss drugs like Ozempic are showing promise beyond diabetes and obesity, including a possible role in cancer prevention," William Brangham said [6].

Data from pooled analyses suggests that overall cancer risk was cut by approximately 20% [7]. Some specific cohorts showed even more significant results, with breast-cancer risk reductions of up to 30% [3].

Dr. Michael O'Connor, lead author of the study, said, "These findings suggest a substantial potential for GLP‑1 drugs to be repurposed in oncology, with breast‑cancer risk reductions of up to 30% in some cohorts" [3].

The research also focused on patients who already have cancer. Dr. Emily Chen, a senior researcher at the University of California, said, "Our data indicate that patients on semaglutide had roughly a 20% lower incidence of cancer progression across several tumor types" [4].

While some data indicate a clear reduction in progression, other researchers noted that the link exists but more studies are needed to confirm the findings [5, 4]. The variation in risk reduction across different tumor types suggests that the drugs may not be equally effective for all forms of cancer.

“One in eight American adults is currently taking a GLP-1 drug.”

If clinical trials confirm these results, GLP-1 agonists could transition from lifestyle and metabolic aids to essential preventative oncology tools. This would likely expand the indicated use of these drugs, potentially increasing global demand and placing further pressure on pharmaceutical supply chains while offering a new non-chemotherapeutic pathway to slow tumor growth.