New FDA warning: The Food and Drug Administration is requiring updated safety labels on all GLP-1 medications because of a possible link to a rare eye condition that can cause permanent vision loss.
Risk is small but serious: An FDA analysis found approximately 6.4 cases of the condition per 100,000 patient-years among GLP-1 users, compared with 3.8 among patients receiving other treatments or a placebo.
Patients should watch for symptoms: Sudden, painless vision loss, blurred vision or blind spots may signal the condition and require immediate medical attention.
Millions of Americans taking popular weight-loss and diabetes medications are being warned about a potentially serious side effect that could threaten their eyesight.
The U.S. Food and Drug Administration announced November 9 that it is requiring new safety warnings on all GLP-1 receptor agonist medications, including Ozempic, Wegovy, Mounjaro and Zepbound, because of evidence suggesting they may increase the risk of a rare eye condition that can cause permanent blindness.
The condition, known as non-arteritic anterior ischemic optic neuropathy, or NAION, occurs when blood flow to the optic nerve is reduced, damaging the nerve that carries visual information from the eye to the brain.
Although the condition is uncommon, the FDA said the potential consequences are serious enough to warrant additional warnings for patients and health care providers.
The agency emphasized that the evidence points to a possible increased risk, not definitive proof that the medications cause the condition.
What the FDA found
The FDA's warning follows an extensive review of clinical trials, observational studies and reports of adverse events involving GLP-1 medications.
According to the agency's November 9 safety communication, researchers analyzed 126 randomized clinical trials involving more than 134,000 patients.
The analysis identified 15 probable cases of NAION. Ten occurred among patients taking GLP-1 medications, while five occurred among patients receiving a placebo.
That translated into approximately 6.4 cases per 100,000 patient-years among GLP-1 users, compared with 3.8 cases among patients receiving a placebo or another type of diabetes medication.
A patient-year represents one patient being followed for one year.
While the difference is relatively small in absolute terms, the FDA said additional observational studies also suggested an increased risk.
The agency's own analysis of real-world diabetes patients found a statistically significant increase in risk compared with one class of diabetes drugs, but not another.
The FDA also acknowledged that patients taking GLP-1 medications frequently have other conditions, including diabetes and high blood pressure, that independently increase their risk of NAION.
That makes determining whether the drugs themselves are responsible especially difficult.
What is NAION?
NAION is sometimes described as an eye stroke because it involves an interruption or reduction of blood flow to the optic nerve.
Unlike some other eye disorders, it typically develops suddenly and without pain.
Patients may wake up one morning and discover that vision in one eye has become noticeably worse.
Symptoms can include blurred vision, blind spots, missing portions of the visual field, distorted colors and reduced sharpness of central vision.
In some cases, the damage can be permanent. There is currently no established treatment that reliably reverses vision loss caused by NAION.
The FDA identified several factors that may increase a person's risk, including diabetes, high blood pressure, smoking, sleep apnea, anemia and kidney disease.
People who have experienced NAION in one eye also face an increased risk of developing the condition in the other eye.
Warning applies to entire class of drugs
The new FDA requirement extends beyond semaglutide, the active ingredient in Ozempic, Wegovy and Rybelsus.
It also covers other GLP-1 medications, including Trulicity, Victoza and Saxenda, as well as the dual-action medications Mounjaro and Zepbound.
The FDA said cases of NAION have been reported among users of all currently marketed GLP-1 medications.
Concerns about a possible connection first attracted widespread attention in 2024, when researchers at Massachusetts Eye and Ear published a study in JAMA Ophthalmology identifying an association between semaglutide use and NAION.
European regulators subsequently reviewed the evidence and concluded in 2025 that NAION was a very rare side effect of semaglutide medications.
The FDA's latest action is broader, requiring the warning across the GLP-1 drug class rather than limiting it to semaglutide.
What patients should do
The FDA is not recommending that everyone taking GLP-1 medications stop treatment.
These medications can provide substantial benefits, including improved blood sugar control, weight reduction and, for certain products and patients, reduced risks of serious cardiovascular and kidney complications.
However, patients should be aware of changes in their vision and seek immediate medical attention if symptoms develop.
Sudden vision loss should be treated as a medical emergency, even if there is no pain.
The FDA is advising health care providers to promptly refer patients with suspected NAION to an ophthalmologist.
If the condition is diagnosed, doctors should consider discontinuing the GLP-1 medication unless its benefits clearly outweigh the potential risks.
Patients who have previously experienced NAION should also discuss their medical history and treatment options with their physicians.
Balancing benefits and risks
The new warning comes as GLP-1 medications have become increasingly important in treating obesity and type 2 diabetes.
For many patients, these medications can improve health outcomes that would otherwise be difficult to achieve.
The FDA's findings suggest that the risk of NAION remains very low, but the consequences can be severe for those affected.
Researchers still do not fully understand why the condition develops or whether GLP-1 medications directly contribute to it. The FDA said animal studies have not identified a biological mechanism explaining the suspected connection.
The agency's message is one of awareness rather than alarm: Patients should understand the potential risk, recognize the warning signs and work with their health care providers to determine whether the benefits of treatment outweigh the risks.
The FDA is also encouraging patients and medical professionals to report suspected adverse reactions through its MedWatch safety reporting program.