There’s no question that the wildly popular injectable weight-loss drugs help people drop pounds, lower heart-disease risk, manage obstructive sleep apnea, and more. But as more people use these drugs, which target hormones including GLP-1, doctors are learning more about the potential downsides, as well.

In the latest study published on MedRxiv—a site that hosts early research not yet peer reviewed by experts—scientists in Canada report that using GLP-1 drugs can contribute to a higher risk of hair loss, especially among women.

Dr. Mohit Sodhi, a resident in emergency medicine at University of British Columbia, and his colleagues analyzed data from just over 1,900 people who were prescribed semaglutide and 1,300 who were prescribed bupropion-naltrexone—an older obesity treatment known as Contrave. Semaglutide is the compound in the drugs Ozempic, which treats diabetes, and Wegovy, which treats obesity. Sodhi focused only on people taking Wegovy to treat overweight or obesity to avoid any potential confounding effects of diabetes on hair loss.

He and his team then compared the diagnoses for hair loss in these patients’ medical records and found that those prescribed semaglutide had a 50% higher risk of being diagnosed with a hair-loss condition compared to those prescribed Contrave. That risk was twice as high for women as for men.

Read More: The Health Risks and Benefits of Weight-Loss Drugs