The latest findings about GLP-1s may leave you feeling queasy.
These blockbuster weight-loss and diabetes treatments have exploded in popularity in recent years, with about one in eight US adults saying they were taking a medication like Ozempic or Wegovy in late 2025.
Now, new research suggests patients taking GLP-1s could face an increased risk of a frightening complication during surgery or in the moments after waking up.
The study was presented earlier this month at the annual meeting of the Association of Anaesthetists of Great Britain and Ireland.
Researchers examined the medical records of 47,039 adults who underwent elective or emergency procedures under the care of an anesthetist across the United Kingdom. About 1,348 patients — or 2.9% — reported taking GLP-1 drugs.
The team found that those patients were more likely to experience regurgitation — that is, they vomited. Most of these cases happened as patients were waking up from anesthesia, though some occurred at the start of surgery or while the procedure was underway.
In all, 17 patients taking GLP-1s suffered regurgitation. Troublingly, two of those cases progressed to aspiration, when stomach contents are accidentally inhaled into the lungs.
That can be incredibly dangerous. Aspiration can cause serious lung damage, including chemical burns, severe breathing problems and aspiration pneumonia. In the most severe cases, it can lead to low blood oxygen, lung infections, respiratory failure or a completely blocked airway.
Overall, the researchers found that pulmonary aspiration and/or regurgitation occurred in about one in 71 patients taking GLP-1s. Among patients not taking the drugs, the rate was about one in 802 — roughly 11 times lower.
Why are weight loss drug users at risk for throwing up?
GLP-1s mimic hormones naturally released by the gut after eating, which help regulate blood sugar, curb hunger and, importantly, slow digestion. That means food can remain in the stomach longer rather than moving rapidly into the intestines.
Anesthesia, meanwhile, relaxes the body and suppresses normal protective reflexes.
Put the two together, and there is a potential problem: If stomach contents come back up while a patient is unconscious or groggy, they can end up in the lungs instead of being swallowed or spit out.
That’s one reason patients are routinely told to fast before surgery. But people taking GLP-1s may still have food or liquid sitting in their stomach longer than expected, even after following standard fasting instructions.
In the UK study, nearly one-third of patients taking the drugs had been advised to stop them eight to 14 days before surgery.
The researchers noted, though, that newer evidence suggests that may not be long enough for the drugs’ effects on the stomach to fully wear off.
“Since tirzepatide and semaglutide have an elimination half-life of 5 and 7 days, respectively, cessation of 25 and 35 days (five half-lives) would be required to effectively eliminate the drug,” the study authors wrote.
Tirzepatide is the active ingredient in drugs including Mounjaro and Zepbound, while semaglutide is the ingredient in Ozempic and Wegovy.
But the study findings don’t mean you should be afraid if you’re taking one of these drugs and need to go under the knife.
The actual chance of a GLP-1 user experiencing regurgitation or aspiration during or shortly after surgery is small. But the potential consequences are serious — and patients may face greater risks if they don’t tell their surgeon or anesthesiologist they’re taking the medications.
That could be more common than doctors realize.
More than 40% of the GLP-1 users in the UK study had obtained their medications outside traditional general-practice or hospital prescribing routes, including through online telehealth services.
“Consequently, people undergoing surgery may not readily report their use, and standard approaches to medicines reconciliation might not include them on admission for surgery,” the researchers wrote.
But the authors did note that their study had some limitations. For example, obesity and diabetes are both known risk factors for pulmonary aspiration, and both conditions are more common among people taking GLP-1 drugs.
That makes it difficult to determine exactly how much of the increased risk can be traced back to the medications themselves.
Even still, the researchers said their findings warrant further studies to identify ways to reduce the risk of aspiration and improve outcomes for surgical patients taking GLP-1s.
That could become increasingly important.
The global GLP-1 boom shows little sign of slowing, with several newer drugs promising even greater biological effects in the pipeline.
In the US, more than 30 million people are expected to be taking GLP-1 drugs by 2030 — about 10 million more than the number estimated to be taking branded versions in 2026, according to JPMorgan projections.
