A new study is drawing attention to a rare but serious brain condition that researchers say may be connected to popular weight-loss and diabetes drugs known as GLP-1 receptor agonists.
The study, published in the journal Clinical Nutrition, identified 15 reported cases of Wernicke encephalopathy in people taking these medications. Wernicke encephalopathy is a neurological disorder caused by a severe deficiency of vitamin B1, and it can lead to confusion, trouble walking, balance problems and vision changes. Left untreated, it can cause permanent neurological damage or death.
Most of the 15 cases involved semaglutide, sold as Ozempic and Wegovy, or tirzepatide, sold as Mounjaro and Zepbound. Researchers pulled the cases from the FDA’s Adverse Event Reporting System, published medical literature and their own medical center’s records.
Most of the patients had reported gastrointestinal symptoms or nutritional problems beforehand, including weight loss, vomiting, loss of appetite or malnutrition. The researchers found that reports of the disorder showed up more often among people taking GLP-1 drugs than among people taking other medications, but they were careful to note the study cannot prove the drugs caused the condition.
Rare, but plausible
Karthik Achari, a Chicago-based clinician and founder of PepMD who was not involved in the study, said the findings deserve context.
“Researchers went through adverse event reports and the medical literature and found a small number of cases, 15, of Wernicke encephalopathy in people taking GLP-1 drugs,” Achari said. “That’s out of millions of people on these medications. So this is rare.”
“But it’s real, it’s serious, and the mechanism makes sense,” he added.
Achari explained that GLP-1 drugs reduce appetite while also causing nausea and vomiting in some patients, which can make it easier for a vitamin B1 deficiency to develop unnoticed.
“The drug shrinks your appetite. It doesn’t shrink your body’s requirements,” he said. “You can now eat very little without feeling it, which is the point of the medication, but your need for protein, vitamins, and fluids didn’t go anywhere.”
Achari said people with persistent nausea and vomiting, those losing weight very quickly while eating little, people with a history of bariatric surgery, and those who drink heavily may be at higher risk.
What patients should watch for
Erin Palinski-Wade, a New Jersey-based nutritionist and author of “The Sleepdemic Solution,” said nutrition and hydration should be treated as part of the treatment plan for anyone on these medications.
“GLP-1 medications can dramatically reduce appetite, but that also means people may unintentionally under-eat the very things their bodies need most, especially protein, fiber and fluids,” she said.
Palinski-Wade warned that ongoing vomiting or diarrhea can raise the risk of dehydration and kidney problems, and said patients should seek medical guidance if those symptoms persist for roughly 24 hours.
“Don’t assume every side effect is just part of being on a GLP-1,” Palinski-Wade said. “Severe or persistent symptoms deserve attention.”
The study’s authors acknowledged their findings rely largely on voluntary reports submitted to the FDA and cannot establish that the medications cause the disorder. They called for further research, and outside experts said patients should not stop taking prescribed GLP-1 medications based on this study alone.
Fox News Digital reported that it reached out to Novo Nordisk, Eli Lilly and the study’s researchers for comment.
