Popular GLP-1 weight-loss drugs linked to potentially deadly brain disorder
Study Finds 15 Cases of Vitamin‑B1 Deficiency Disorder in GLP‑1 Weight‑Loss Drug Users
A recent analysis published in Clinical Nutrition identified 15 reports of Wernicke encephalopathy—a brain disorder caused by severe thiamine (vitamin‑B1) deficiency—in patients taking glucagon‑like peptide‑1 (GLP‑1) receptor‑agonist medications. The cases were located through the U.S. Food and Drug Administration’s Adverse Event Reporting System (FAERS), peer‑reviewed literature, and an independent medical center.
The patients were prescribed the most widely used GLP‑1 drugs, including semaglutide (sold under the brand names Ozempic and Wegovy) and tirzepatide (marketed as Mounjaro and Zepbound). Most of the reported cases involved gastrointestinal complaints such as nausea, vomiting, loss of appetite, and rapid weight loss, all of which can impair nutritional intake.
Although the study did not establish a direct causal link, the authors noted that the frequency of reported cases appeared higher among GLP‑1 users compared with users of other medications. “We cannot prove that the medications caused the condition,” the researchers said, adding that further investigation is needed.
Wernicke encephalopathy can manifest as confusion, difficulty walking, balance problems, and visual disturbances. If left untreated, the disorder may progress to permanent neurological damage or death, underscoring the seriousness of the condition.
Karthik Achari, a Chicago‑based clinician and founder of PepMD who was not involved in the study, emphasized the rarity of the reports. “Out of millions of people on these medications, 15 cases is rare,” he told Fox News Digital. “But it’s real, it’s serious, and the mechanism makes sense.” Achari explained that GLP‑1 drugs reduce appetite while also producing nausea and vomiting, which can lower intake of essential nutrients without reducing the body’s requirement for them.
He identified several groups that may be at higher risk: individuals with persistent nausea or vomiting, those experiencing rapid weight loss with minimal food consumption, patients who have undergone bariatric surgery, and heavy alcohol users.
Nutritionist Erin Palinski‑Wade, based in New Jersey, stressed the importance of adequate nutrition and hydration while on GLP‑1 therapy. “These medications can dramatically reduce appetite, so patients may unknowingly miss out on protein, fiber, and fluids,” she said. Palinski‑Wade cautioned that ongoing vomiting or diarrhea can exacerbate dehydration and lead to kidney problems. She urged patients to seek medical guidance if such symptoms persist for about 24 hours, noting that “severe or persistent symptoms deserve attention.”
The researchers acknowledged that their analysis relied heavily on voluntary reports submitted to the FDA, limiting the ability to draw firm conclusions. They called for additional studies to better understand the relationship between GLP‑1 medications and thiamine deficiency.
Medical experts advised patients not to discontinue their prescribed GLP‑1 therapy based solely on the findings. “The benefits of these drugs for weight management and cardiovascular risk reduction are well documented,” one clinician noted. “Patients should continue to monitor their symptoms and discuss any concerns with their healthcare provider.”
Fox News Digital reached out to the manufacturers Novo Nordisk and Eli Lilly, as well as the study’s authors, for comment. No responses were received at the time of publication.