Pancreatitis Risks From Ozempic, Mounjaro Being Investigated by U.K. Regulators

At least 10 pancreatitis deaths among users of Ozempic and other GLP-1 medications have occurred in the U.K. since the new class of weight loss and diabetes were first introduced.

Health officials in the United Kingdom want users of Ozempic, Mounjaro, Wegovy, Saxenda and similar medications to report any experiences with acute pancreatitis while, or after, using the popular diabetes and weight loss drugs.

The U.K.’s Medicines and Healthcare products Regulatory Agency (MHRA) issued the request in a press release late last month, as part of a broader investigation into the potential side effects of GLP-1 receptor agonists, and an investigation into whether certain genetic factors may make some users more likely to develop pancreatitis.

The most widely used GLP-1 medication is Novo Nordisk’s Ozempic (semaglutide), which was originally approved in 2017 to treat type 2 diabetes. However, its weight loss effects later led to the development of Wegovy, a version approved specifically for obesity. Eli Lilly’s competing drug, Mounjaro (tirzepatide), is also approved for diabetes, with a weight loss counterpart marketed as Zepbound. Other drugs in the GLP-1 class include Saxenda, Byetta, Victoza, Trulicity, Rybelsus and others.

Since their introduction onto the market, Ozempic and other GLP-1s have become wildly popular, and there is growing evidence that the drugs may effectively treat a wide range of ailments. However, a growing number of individuals across the U.S. are now pursuing Ozempic lawsuits, Mounjaro lawsuits, Wegovy lawsuits and claims against the makers of other GLP-1 medications, indicating that all of the potential side effects and health risks were not adequately disclosed to users and the medical community.

Most of the concerns over GLP-1 drug side effects have focused on the risks of gastrointestinal problems, such as gastroparesis, also known as stomach paralysis, intestinal blockages and ileus. Recent months have also seen new scientific evidence of Ozempic vision problems, which can lead to sudden and permanent vision loss.

However, data released by the MHRA in early June revealed the agency was receiving a high number of pancreatitis cases that may be linked to GLP-1 use, some of them fatal. Pancreatitis has long been linked to the class, with the U.S. Food and Drug Administration (FDA) issuing a Byetta pancreatitis alert in 2008.

As of the end of May 2025, the MHRA has linked at least five pancreatitis-related deaths to users of Mounjaro and Wegovy, and one death linked to Ozempic. In addition, the agency received at least 116 reported cases of acute and chronic pancreatitis by users of Saxenda, which resulted in at least one death. Another 101 incidents were linked to Byetta, resulting in three deaths.

“GLP-1 medicines like Ozempic and Wegovy have been making headlines, but like all medicines there can be a risk of serious side effects. We believe there is real potential to minimise these with many adverse reactions having a genetic cause.”

-Matt Brown, Chief Science Officer for Genomics England, MHRA press release

The MHRA’s investigation, through its Yellow Card Biobank and a company known as Genomics England, will attempt to determine if there is a genetic cause as to why some users suffer severe pancreatitis problems while others do not. The Yellow Card system is the MHRA’s adverse drug event reporting program.

GLP-1 Lawsuits in the U.S.

There are nearly 2,000 GLP-1 lawsuits currently being pursued throughout the United States’ federal court system, focusing on gastrointestinal injuries, which have been centralized in the Eastern District of Pennsylvania under U.S. District Judge Karen Marston, as part of a GLP-1 lawsuit multidistrict litigation (MDL).

To help test how juries may respond to certain evidence and testimony that will be central throughout thousands of individual claims, Judge Marston is presiding over coordinated discovery and pretrial proceedings to prepare a small group of cases for early trial dates.

While the outcomes of these early test cases will not be binding on other claims, they will be closely watched and may help the parties negotiate GLP-1 settlements to resolve large numbers of lawsuits in the future.

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