Serious 'Unusual' Ozempic Side Effect Becoming 'Increasingly Common'

New research shows that popular GLP-1 weight-loss drugs such as Ozempic, Wegovy and Mounjaro may be throwing off critical medical imaging scans, which could lead to delayed diagnoses and treatments for serious diseases, according to EurekAlert!

The medications, which were initially intended to treat Type 2 diabetes, have seen a 700% increase in usage between 2019 and 2023 in the United States due to their powerful weight-loss effects as they mimic the natural GLP-1 hormone that regulates blood sugar and appetite, while also boosting insulin production, slow digestion and having the patient feel full longer. These factors can lead to record weight loss and improved health, but also potentially interfere with PET-CT scans used by doctors to detect cancer and inflammatory diseases.

Unusual patterns of hot spots that can mask signs of cancer or make healthy tissues in the body seem diseased have reportedly been found in the bodies of patients who take GLP-1s.

“We noticed unusual uptake in one of our patients on a GLP-1 agonist, which prompted a wider review across our network,” said Dr. Peter Strouhal, medical director at Alliance Medical Ltd in the UK and lead author of the new study, in a statement.

“We found that these altered patterns are increasingly common, yet there is currently no national or international guidance in the UK addressing this emerging issue,” he added.

About 1 in 8 adults in the United States have used a GLP-1 medication, according to a survey conducted by the Kaiser Family Foundation in 2024, which doctors say is concerning given the potential cancer detection issues.

“Recognizing the characteristic uptake associated with GLP-1 agonists helps avoid unnecessary anxiety and interventions, ensuring patients receive the right care, at the right time, without detours or doubt,” Strouhal said.

Strouhal and his colleagues are recommending patients stop taking GLP-1 medications prior to undergoing PET-CT scans and that imaging teams carefully document the patients' medication histories so doctors have a better understanding on the situation.