# A rare brain risk hiding behind GLP-1 weight loss

> Fifteen cases of a vitamin B1 brain disorder turned up in people on Ozempic, Wegovy, Mounjaro and Zepbound.
- Title: A rare brain risk hiding behind GLP-1 weight loss · Fox News
- Summary: Fifteen cases of a vitamin B1 brain disorder turned up in people on Ozempic, Wegovy, Mounjaro and Zepbound. GLP-1 drugs shrink your appetite, not your need…
- Keywords: glp-1, ozempic, nutrition, brain health, drug safety, news, politics, rare, brain, risk, hiding, behind
- Source: Fox News — https://foxnews.com/health/popular-glp-1-weight-loss-drugs-linked-potentially-deadly-brain-disorder
- Author: Kelly McGreal
- Published: 2026-09-13T00:00:00+00:00
- Read time: 1 min
- Topics: glp-1, ozempic, nutrition, brain health, drug safety, news, politics
## A warning attached to GLP-1s
Researchers flagged a rare but potentially fatal brain condition in people taking GLP-1 weight-loss drugs. The findings ran in the journal Clinical Nutrition.
## Fifteen cases, one disorder
The study found 15 reported cases of Wernicke encephalopathy, a neurological disorder caused by severe vitamin B1 deficiency. Most involved semaglutide or tirzepatide.
## Where the cases came from
The team pulled reports from the FDA's adverse event database, published medical literature and their own medical center. Reports showed up more often with GLP-1s than with other drugs.
## What B1 loss does
Thiamine keeps the brain running. Severe deficiency brings confusion, trouble walking, balance problems and vision changes, and untreated it can cause permanent damage or death.
## Rare, but real
Clinician Karthik Achari put 15 cases against millions of users and called it rare. He also said the biology behind it holds up.

> But it's real, it's serious, and the mechanism makes sense.
## Appetite shrinks, needs don't
Nausea, vomiting and a suppressed appetite make it easy to eat far too little. Risk climbs with fast weight loss, past bariatric surgery, or heavy drinking.

> The drug shrinks your appetite. It doesn't shrink your body's requirements.
## Don't quit, do eat
Nutritionist Erin Palinski-Wade says protein, fiber and fluids are part of the treatment. Call a doctor if vomiting or diarrhea runs about 24 hours, and don't stop a prescription over this study.

> Don't assume every side effect is just part of being on a GLP-1.
## Key takeaway

GLP-1 drugs shrink your appetite, not your need for protein, vitamins and fluids. Eat and drink deliberately, and treat severe vomiting as a reason to call your doctor.