A recent study has linked popular GLP-1 weight-loss drugs to a rare brain disorder, raising concerns about vitamin B1 deficiency among users.
Researchers are sounding the alarm over a rare but potentially life-threatening brain condition associated with popular GLP-1 weight-loss medications. A new study published in Clinical Nutrition has identified 15 reported cases of Wernicke encephalopathy, a neurological disorder stemming from severe vitamin B1 deficiency, in individuals taking GLP-1 receptor agonists.
The majority of these reported cases involved semaglutide, marketed under the brand names Ozempic and Wegovy, as well as tirzepatide, sold as Mounjaro and Zepbound. The researchers uncovered these cases through the FDA’s Adverse Event Reporting System (FAERS), published medical literature, and their own medical center.
Patients in the study commonly reported gastrointestinal symptoms or nutritional issues, including weight loss, vomiting, loss of appetite, or malnutrition. Notably, the incidence of Wernicke encephalopathy appeared more frequently among those using GLP-1 medications compared to individuals taking other drugs. However, the researchers stressed that the study does not establish a direct causal link between the medications and the condition.
Vitamin B1 plays a crucial role in brain function, and severe deficiencies can lead to confusion, difficulty walking, balance issues, and changes in vision. If left untreated, Wernicke encephalopathy can result in permanent neurological damage or even death.
Karthik Achari, a clinician based in Chicago and founder of PepMD, emphasized the need to view the findings in 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 told Fox News Digital. “That’s out of millions of people on these medications. So this is rare.”
However, he acknowledged the seriousness of the findings. “It’s real, it’s serious, and the mechanism makes sense,” he added. Achari explained that GLP-1 medications can suppress appetite while also causing nausea and vomiting, which may lead some individuals to become deficient in vitamin B1.
“The drug shrinks your appetite. It doesn’t shrink your body’s requirements,” he noted. “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.” Individuals experiencing persistent nausea and vomiting, rapid weight loss while consuming minimal food, those with a history of bariatric surgery, and heavy alcohol users may be at a heightened risk for vitamin B1 deficiency.
Erin Palinski-Wade, a New Jersey-based nutritionist and author of The Sleepdemic Solution, stressed the importance of proper nutrition and hydration as part of the treatment plan for those taking GLP-1 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 told Fox News Digital.
Palinski-Wade also warned that ongoing vomiting or diarrhea can increase the risk of dehydration and kidney problems. She advised patients to seek medical guidance if these symptoms persist for approximately 24 hours. “Don’t assume every side effect is just part of being on a GLP-1,” she cautioned. “Severe or persistent symptoms deserve attention.”
The researchers acknowledged that their study relied heavily on reports submitted to the FDA and cannot definitively prove that GLP-1 medications caused Wernicke encephalopathy. They called for further research to explore this potential link. Experts have advised that patients should not discontinue their prescribed GLP-1 medications based solely on these findings.
Fox News Digital reached out to Novo Nordisk, Eli Lilly, and the researchers for comment regarding the study and its implications.