European health officials are warning that the popular weight-loss drugs Ozempic and Wegovy can cause a potentially dangerous eye condition as a side effect.

The European Medicines Agency’s safety committee says a review of drugs containing semaglutide, otherwise known as GLP-1 drugs, showed a possible increased risk in users of developing non-arteritic anterior ischemic optic neuropathy, an eye condition that may cause vision loss. A type 2 diabetes drug, Rybelsus, is also included in the warning.

The safety committee calls the side effect “very rare,” affecting up to 1 in 10,000 people, but still recommends that the side effect be added to the product information for the Novo Nordisk-produced drugs.

The European Union’s health body warns patients if they experience a sudden loss of vision or rapidly worsening eyesight during treatment with semaglutide, they should immediately contact a doctor. If the condition is confirmed, treatment with semaglutide should be stopped.

Government health officials say results from several large studies suggest that exposure to semaglutide in adults with type 2 diabetes doubles the risk of developing the condition compared with people not taking the medicine. This corresponds to approximately one additional case per 10,000 people.

Data from clinical trials also point to a slightly higher risk of developing the condition in people taking semaglutide, compared with people taking placebo.

Semaglutide acts in the same way as GLP-1 — a natural hormone in the body — by increasing the amount of insulin that the pancreas releases in response to food. This helps with the control of blood glucose levels. Semaglutide also regulates appetite by increasing a person’s feelings of fullness, while reducing hunger and cravings.

Use of the drugs for weight loss has exploded in the United States, with one in eight people taking a GLP-1 agonist at some point, and 6 percent currently taking the drug, according to a 2024 KFF report.

The new labeling recommendations will now be sent to another committee to adopt the agency’s opinion. The European Commission will then issue a final, legally binding decision to be followed by the entire EU.