U.K. agency issues warning over Ozempic, other GLP-1 drugs for potential vision loss

A file photo of semaglutide injections.

The United Kingdom’s regulatory body for medicine and health-care products issued a warning for patients using semaglutide – a glucagon-like peptide-1 receptor agonist (GLP-1s) sold under Ozempic, Wegovy and Rybelsus brands – for a rare risk of vision loss.

The U.K.’s Medicines and Healthcare products Regulatory Agency (MHRA) published a press release last Thursday, saying the medicine, usually prescribed to patients with Type 2 diabetes or for weight management, can cause an “extremely rare ischemic event,” resulting in reduced blood flow to the front of the optic nerve.

This event – called non-arteritic anterior ischemic optic neuropathy (NAION) – causes “sudden, painless vision loss in one eye,” with patients describing it as “blurring or cloudiness of vision,” the press release said.

Dr. Mahyar Etminan, a drug safety epidemiologist with Epilytics, told CTVNews.ca in an email that use of GLP-1 agonists like Ozempic and Wegovy can increase the risk of vision loss, independent of other risk factors.

“Those with diabetes and cardiovascular disease might be at a higher risk, but we are also seeing them in people otherwise healthy who are taking these drugs to just lose a few pounds,” Etimnan said Monday.

The MHRA warns that patients who are taking semaglutide and experiencing a change in their eyesight should “urgently” seek medical attention, preferably eye-care specialists.

“While the potential risk of NAION for patients prescribed semaglutide is extremely small, it is important that patients and health-care professionals are alert to the associated symptoms,” Dr. Allison Cave, the MHRA’s chief safety officer, said in the news release.

According to the MHRA, studies suggest that this event could affect up to one in 10,000 people who are taking semaglutide.

‘Seek medical advice immediately’ if vision changes: doctor

Since the use of semaglutide was first authorized in the U.K. in 2018, three “spontaneous” reports of vision impairment associated with the drug have been reported as of August 2025, the press release added.

“The MHRA is reviewing any evidence for an association with other GLP-1 agonists,” it said.

However, Etminan said it was important to tell people that it is a rare occurrence.

“People should not be alarmed, but if anyone on these drugs notices a change in vision, they need to seek medical advice immediately,” he added.

Meanwhile, Etminan said he is not aware of any cases of vision loss connected with semaglutide reported in Canada.

While Ozempic and other prescription-based semaglutide medications are authorized in Canada to treat Type 2 diabetes and cardiovascular diseases, Wegovy is known to be approved for prescription for weight loss, according to the Canadian Medical Association.

Canadians can only get GLP-1 drugs with a prescription from their health-care provider.

In January, Health Canada issued a public advisory warning that counterfeit versions of Ozempic, Rybelsus and Wegovy were being sold in various retailers in Canada.

“Some websites and social media advertisements misuse official Health Canada logos and display fake endorsements to mislead consumers,” the advisory said.

Diabetes Canada has previously warned Canadians about a surge in misleading online advertisements that use forged logos from Diabetes Canada or Health Canada, claim counterfeit endorsements and promote products that don’t exist, or are not approved.

With files from CTV News’ Dorcas Marfo