The legal scrutiny surrounding some of the biggest names in weight loss medicine is widening as patients claim popular GLP-1 drugs caused sudden and potentially permanent vision loss.
The latest GLP-1 lawsuits center on nonarteritic anterior ischemic optic neuropathy, known as NAION, a rare condition caused by reduced blood flow to the optic nerve. According to The Wall Street Journal, patients have sued Novo Nordisk and Eli Lilly alleging medications including Ozempic, Wegovy and Zepbound caused the condition and that they were not adequately warned about the risk. Both drugmakers dispute the allegations and have challenged claims that their medications caused the injuries.
The cases have grown into a significant federal proceeding. According to the U.S. Judicial Panel on Multidistrict Litigation, the NAION litigation is being coordinated as MDL No. 3163 in the Eastern District of Pennsylvania before U.S. District Judge Karen S. Marston. The panel’s September 1, 2026 statistics show 216 actions pending in the vision loss MDL.
The vision claims arrive as regulators outside the United States have taken stronger action on semaglutide, the active ingredient in Ozempic, Wegovy and Rybelsus. In June 2025, the European Medicines Agency concluded that NAION should be classified as a very rare side effect of semaglutide. Its safety committee said epidemiological studies suggested roughly a twofold increase in risk among adults with type 2 diabetes, translating to approximately one additional NAION case per 10,000 person-years of treatment.
The EMA recommended that patients experiencing sudden vision loss or rapidly worsening eyesight seek medical attention immediately and that semaglutide treatment be stopped if NAION is confirmed. The United Kingdom later updated semaglutide product information, while Australia’s Therapeutic Goods Administration announced broader GLP-1 class warnings in July 2026 covering drugs including semaglutide, tirzepatide and dulaglutide.
The situation is different in the United States. The Wall Street Journal reported that the FDA continues to investigate the issue. Current U.S. prescribing information for Ozempic contains warnings involving other eye complications, but NAION is not listed among its warnings and precautions. That difference between U.S. labeling and overseas regulatory action has become an important part of the expanding GLP-1 lawsuits.
Researchers are still working through the strength of the association. A 2025 JAMA Network Open study involving more than 1.5 million eligible patients with type 2 diabetes found that treatment with semaglutide or tirzepatide was associated with increased risks of NAION and certain other optic nerve disorders compared with other diabetes medications, although researchers stressed that the overall absolute risk was low.
Another study published in JAMA Ophthalmology found a modest increase in NAION risk associated with semaglutide, but researchers said an additional study was necessary to understand causality and clinical significance. Other research has produced inconsistent results, which is one reason the medical and legal questions remain contested even as regulators in some countries have changed warning labels.
Vision loss is also only one part of the safety debate.
A separate wave of GLP-1 lawsuits has been underway for years over gastrointestinal injuries. Federal court records show those cases are being handled separately as MDL No. 3094. According to the September 1 report from the Judicial Panel on Multidistrict Litigation, that proceeding had 4,022 pending actions, making it far larger than the newer vision loss litigation.
According to the federal court overseeing MDL 3094, plaintiffs have raised claims involving gastroparesis, ileus, intestinal obstruction, gallbladder disease and gallstones, severe gastrointestinal disease, deep vein thrombosis and secondary malnutrition. Novo Nordisk and Eli Lilly deny the allegations. The existence of the litigation does not establish that the medications caused any individual plaintiff’s condition.
Some serious gastrointestinal risks are already recognized in U.S. prescribing information. The current Wegovy prescribing information warns about acute pancreatitis, acute gallbladder disease, kidney injury related to dehydration, and severe gastrointestinal reactions. Wegovy is not recommended for patients with severe gastroparesis.
The current Ozempic label similarly warns about pancreatitis, diabetic retinopathy complications, kidney injury related to volume depletion, severe gastrointestinal reactions, and gallbladder disease. It also warns about rare reports of pulmonary aspiration during general anesthesia or deep sedation because semaglutide can delay stomach emptying.
Eli Lilly’s Zepbound prescribing information carries warnings involving severe gastrointestinal reactions, acute kidney injury due to dehydration, gallbladder disease, pancreatitis, diabetic retinopathy complications, and pulmonary aspiration. Both semaglutide and tirzepatide products also carry boxed warnings concerning thyroid C-cell tumors observed in animal studies, while the labels state that it remains unknown whether the drugs cause those tumors in humans.
Those warnings exist alongside documented benefits. U.S. prescribing information shows Ozempic is approved not only to improve blood sugar control in adults with type 2 diabetes but also for certain cardiovascular and kidney risk reductions. That makes the developing safety picture less about declaring GLP-1 drugs universally dangerous and more about determining which risks are real, how frequently they occur, and whether patients received adequate information before treatment.
As GLP-1 lawsuits involving gastrointestinal injuries move through one federal proceeding and vision loss cases move through another, courts, regulators, and researchers are now examining the same central question from different angles: whether the rapidly expanding use of these medications has moved faster than the understanding and communication of some of their rare but potentially serious risks.
