Medications widely used for weight loss may have health effects that extend beyond changes on the scale. In a large study of adults with obesity who did not have diabetes, people prescribed GLP-1-based medications had a lower incidence of obesity-related cancers than similar patients who received counseling on diet and exercise alone.
The observational study, published in the Annals of Oncology, does not prove that medications such as semaglutide and tirzepatide prevent cancer. Researchers followed patients for only two years, and people who receive prescription medications may differ from those who receive lifestyle counseling in ways that cannot be fully captured in medical records. Still, the findings add to growing interest in whether treatments that support weight loss may also affect longer-term health risks.
Researchers analyzed health records from 229,467 U.S. adults with obesity who did not have diabetes. The average age was 47. The records came from TriNetX, a nationwide database covering 113 million patients.
Among the patients included in the initial analysis, 86,422 had prescriptions for semaglutide or tirzepatide and 143,045 received advice about diet and exercise. The researchers then matched patients in the two groups based on factors that could affect cancer risk, creating two comparison groups of 80,899 people each.
Over an average follow-up period of two years, patients prescribed the medications had a 41% lower incidence of obesity-related cancers than those in the diet and exercise counseling group.
Excess body weight has been linked to 13 types of cancer, including endometrial, breast, colorectal, kidney, pancreatic, thyroid, ovarian, esophageal, stomach, liver and gallbladder cancers, as well as multiple myeloma and meningioma.
The researchers also found a 58% lower incidence of endometrial cancer among patients prescribed the medications. This finding is notable because endometrial cancer is closely linked to obesity.
Some subgroup findings raised additional questions. Among men, medication use was associated with a nearly 70% lower incidence of obesity-related cancers. The reduction was approximately 50% among white patients, but researchers did not observe the same association among Black patients. The study could not determine the reasons for that difference. The authors said access to care, different risk profiles and biological factors may warrant further investigation.
The strongest association among the medications studied was observed in patients prescribed tirzepatide. Tirzepatide acts on both GLP-1 and GIP receptors, while semaglutide acts on GLP-1 receptors. However, the findings do not establish that one medication is more effective than another at lowering cancer risk.
GLP-1-based medications were originally developed to treat diabetes. Some are now prescribed for weight management because they can reduce appetite, increase feelings of fullness and support substantial weight loss.
Researchers have been examining whether these medications may also affect other health outcomes. Because obesity is associated with an increased risk of several cancers, it is plausible that treatments supporting weight loss could influence cancer risk. The medications may also affect inflammation, metabolism or other biological pathways. This study was not designed to determine which mechanisms may be involved.
“Our study suggests GLP-1 RAs may have benefits that extend beyond weight management,” said Pedro Ramirez, chair of the Department of Obstetrics and Gynecology at Houston Methodist Hospital and the study’s second author. “It should be noted that while the findings do not prove that GLP-1 drugs directly prevent cancer, they provide early evidence that deserves further study in long-term clinical trials.”
That distinction matters. The study was based on health records, not a randomized controlled trial. Researchers used statistical methods to make the two groups more comparable, but those methods cannot account for every possible difference between patients.
The comparison group also consisted of people who received diet and exercise counseling. The study did not measure whether patients followed that advice or whether their eating habits, physical activity levels or weight changed over time.
The relatively short follow-up period is another important limitation. Many cancers develop over a longer timeframe, so researchers will need longer studies to understand whether the association persists and whether the medications directly affect cancer risk.
The findings do not mean that people should take GLP-1-based medications solely to prevent cancer. These medications have potential benefits, side effects and costs that should be discussed with a health care provider based on a person’s individual needs.
“Our findings do not prove causation, and cancer risk reduction should not yet be a stand-alone reason to prescribe GLP-1 RAs,” said Aparna Kamat, director of the Division of Gynecologic Oncology at Houston Methodist Hospital and the study’s senior author.
For people who are already considering medication as part of obesity treatment, the study offers an encouraging but preliminary signal. It also gives researchers another reason to continue examining how weight-loss treatments may affect health well beyond the scale.
The authors reported no funding for the study and declared no conflicts of interest.