FDA orders blindness risk warning on weight loss drugs

Companies making popular weight loss drugs, including Ozempic and Wegovy, will be required to add a warning label about a rare eye condition that can cause blindness, the US Food and Drug Administration (FDA) has said.

The FDA said the condition, called non-arteritic anterior ischemic optic neuropathy (NAION) - which can cause permanent vision loss - was reported with all GLP-1 drugs, the medications used to treat obesity, diabetes and several other medical conditions.

The new requirement applies to a dozen injectable or pill-based drugs, including widely used brands such as Zepbound and Mounjaro.

NAION is caused by decreased blood flow to the optic nerve, although the underlying cause is not understood, the FDA said.

Symptoms of the condition include blurred vision, blind spots, distorted colours and other visual disturbances, according to the FDA, which urged patients experiencing such problems to contact a healthcare professional immediately.

The agency said it began looking into the issue following the publication of a 2024 medical paper linking the condition to certain patients taking semaglutide - the active drug in Ozempic, which is produced by pharmaceutical company Novo Nordisk.

An FDA analysis of more than 125 clinical trials found that the problem occurred in roughly six of every 100,000 patients who took a GLP-1 for at least one year.

The comparable rate for people taking a placebo or other types of glucose-lowering medications was less than four in every 100,000 patients, the FDA said.

It added that it also found reports of the problem in its electronic reporting system for drug injuries and side effects.

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Novo Nordisk, which also manufactures Wegovy, said it "continues to believe the data do not establish a cause-and-effect relationship and we remain confident in the benefit-risk profile of our ‌GLP-1 medicines".

A spokesperson for Eli Lilly, which produces Mounjaro and Zepbound, said: "FDA's drug safety communication applies to all medicines with GLP-1 RA activity and does not reference any findings specific to Lilly medicines.

"We are carefully ​evaluating the update and will respond to FDA promptly."

According to a Gallup poll, the percentage of US adults who take GLP-1 medications for weight loss purposes has risen from 3% in 2024 to 11% in 2026.

In the UK, Wegovy is regularly prescribed on the NHS to treat weight loss, while Ozempic is given out for the treatment of type 2 diabetes, according to the Department of Health.

Earlier this year, researchers found that weight loss drugs were linked to an increased risk of hair loss following a study on about 50,000 people.

(c) Sky News 2026: FDA orders blindness risk warning on weight loss drugs