US warns of rare vision loss risk linked to Ozempic, Wegovy, Mounjaro

The US Food and Drug Administration (FDA) has issued a new warning about several widely used diabetes and weight-loss medications, including Ozempic, Wegovy, Mounjaro, and Zepbound, after identifying a possible link to an increased risk of a rare eye condition known as non-arteritic anterior ischemic optic neuropathy (NAION), which can lead to vision loss.

The FDA informed patients and healthcare providers that it will require manufacturers of these drugs to add a warning about this risk to the 'Warnings and Precautions' section of their prescribing information. This decision follows a review of clinical trial data, animal studies, post-marketing reports, observational studies, and case reports.

NAION is one of the most common causes of sudden, painless vision loss and can sometimes result in permanent impairment. The condition occurs due to reduced blood flow to the front part of the optic nerve, though its underlying causes are not yet fully understood.

Commenting on the decision, Eli Lilly, which manufactures Mounjaro and Zepbound, said the warning applies to all drugs acting on GLP-1 receptors and does not point to specific findings about its own products. The company added that it is reviewing the update and will respond to the FDA. Novo Nordisk, which produces Ozempic and Wegovy, stated that it does not believe current data establish a causal relationship between its medications and the condition, expressing confidence in the overall benefit-risk profile of its treatments.

In June 2025, the European Medicines Agency's safety committee indicated that up to one in 10,000 people using semaglutide—the active ingredient in Ozempic and Wegovy—for at least a year could be affected, marking the first regulatory confirmation of this potential side effect. A large-scale study published in March 2025 involving about 175,000 diabetes patients treated with semaglutide and a similar group on other medications found that the risk of NAION more than doubled after two years of GLP-1 therapy compared to other drugs.

Denmark's patient compensation authority has also awarded compensation to four patients who experienced vision loss after using Novo Nordisk medications.

Despite the warning, analysts at Citi noted that the rarity of the condition, along with the proven benefits of these drugs for weight loss, blood sugar control, and improvements in heart, kidney, and sleep apnea outcomes, may limit the impact on prescribing, according to CNN.

The US warning has renewed focus on the potential risks associated with GLP-1 drugs, which are widely used for diabetes and weight management, even as manufacturers maintain that current data do not prove a direct causal link to vision loss.