GLP-1 medications have transformed the way people lose weight. But emerging evidence suggests the popular drugs may also carry serious health risks.

GLP-1 receptor agonists — commonly prescribed to treat Type 2 diabetes and for chronic weight management — include semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).

According to a survey by the Kaiser Family Foundation, an estimated 12% of Americans are taking GLP-1 receptor agonists. As use has surged, however, so have lawsuits alleging harmful side effects.

In recent years, thousands of lawsuits have been filed against the manufacturers of GLP-1 drugs. Plaintiffs claim the pharmaceutical companies failed to adequately warn patients and doctors about potential side effects, including severe gastrointestinal problems and other serious health complications.

According to USA Today, the cases include a Maryland truck driver who suffered an “eye stroke” that left him blind, a Louisiana woman diagnosed with a brain dysfunction linked to a vitamin deficiency, and an Oklahoma real estate agent who experienced a ruptured colon.

Since the first lawsuit was filed in 2023, at least 4,400 patients have joined consolidated federal and state litigation.

The suits target Danish pharmaceutical company Novo Nordisk, which manufactures Ozempic and Wegovy, and Indiana-based Eli Lilly, the maker of Trulicity, Mounjaro, and Zepbound.

The alleged health complications are serious:

• About 75% of federal cases involve gastroparesis, a condition in which the stomach empties too slowly. Gastroparesis can cause persistent nausea, vomiting, abdominal pain, and severe bloating, significantly affecting quality of life. Plaintiffs argue manufacturers did not provide adequate warnings about this risk.

• Roughly 18% of lawsuits allege the drugs caused ileus, a condition in which the intestines fail to move food and waste through the body.

• Another 18% claim intestinal obstructions.

• About 8% report gallbladder problems, some requiring surgery.

• An additional 8% allege serious gastrointestinal complications — including vomiting, chronic acid reflux, or abdominal pain — that required hospitalization.

The totals exceed 100% because some patients reported multiple conditions, according to USA Today.

Both major manufacturers maintain that their products’ safety profiles are well established and that labeling has been approved by the U.S. Food and Drug Administration.

Company representatives say they will continue working closely with regulators to ensure product safety.

While current product labels warn of potentially severe gastrointestinal complications, other reported conditions — including the blindness experienced by the Maryland truck driver — are only now gaining attention.

The 63-year-old man, who is now legally blind, was diagnosed with non-arteritic anterior ischemic optic neuropathy, known as NAION.

European regulators recently updated Wegovy and Ozempic labels to warn that the drugs may cause NAION in up to 1 in 10,000 cases. U.S. labels for GLP-1 drugs warn of vision changes but do not specifically mention NAION.

The American Academy of Ophthalmology has not issued a blanket warning against using the drugs, stating that a “review of the available data has not established that semaglutide causes NAION, only a potential link between the two.”