- GLP-1 receptor agonists, a class of medication used to treat type 2 diabetes and obesity, are sold under many brand names, including Wegovy, Ozempic, and Mounjaro.
- Although rare, these injections have been linked to a few side effects, including acute pancreatitis, or the inflammation of the pancreas.
- Following a recent rise in such reports, the U.K. has updated its guidance on weight-loss injections.
- Experts agree that this should not be a cause for alarm, but that people should be informed about this risk and the signs of pancreatitis to look out for.
GLP-1 agonists like Wegovy, Ozempic, and Mounjaro, which are used to treat type 2 diabetes and obesity, have been growing in popularity — so much so that in December 2025, the Food and Drug Administration (FDA) approved an oral pill form of Wegovy for weight loss.
However, as life changing as these medications have been for some people, they have also been linked to a few serious but rare side effects. One of these effects, which has come under scrutiny recently, has been acute pancreatitis.
The latest body to take action on this is the Medicines and Healthcare Products Regulatory Agency (MHRA) in the United Kingdom, which recently updated its guidance on these weight loss jabs, citing a rise in cases of acute pancreatitis reported to the Yellow Card scheme, which monitors adverse reactions to medications.
Acute pancreatitis is the inflammation of the pancreas, presenting with symptoms such as sudden abdominal pain, nausea, and swelling. The patient information leaflets for drugs such as Wegovy, Ozempic, and Mounjaro state that pancreatitis is an “uncommon” side effect, affecting about one in 100 patients.
Data shows that 1.6 million adults in England, Wales, and Scotland used a GLP-1 medication for weight loss between 2024 and 2025.
In the U.K., between 2007 and October 2025, 1,296 yellow card reports of pancreatitis linked to GLP-1 receptor agonists or dual GLP-1/GIP receptor agonists were reported, of which 19 were fatal.
Medical News Today spoke to three medical experts — Hector Perez, MD, a board-certified bariatric surgeon at Renew Bariatrics and an advisor at BestSurgeons, Mir Ali, MD, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, and David Cutler, MD, a board-certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA — about weight loss injections, their side effects, and how to spot signs of acute pancreatitis.
Describing the MHRA update as “responsible risk management”, Perez said that the decision was in line with real-world data.
“GLP-1 receptor agonists and related incretin therapies absolutely have a known pancreatic signal in post-marketing surveillance and case reports. It’s rare, but serious enough that regulators in multiple countries are now watching more closely. What’s different here is that U.K. clinicians and regulators are reacting to clusters in real patients rather than just isolated reports, and that matters,” he told MNT.
Ali said the updated guidance should not scare users and that the decision took patient safety into account.
“The risk of pancreatitis with GLP-1 agonist medications is well-documented, though the incidence remains very low (0.27% to 2.2%, depending on the study). The increase in reported cases is likely due to the widespread use of these medications. The U.K.’s updated guidance is consistent with existing medical guidelines,” he said.
Meanwhile, Cutler reassured GLP-1 users that “pancreatitis is a recognized, but uncommon risk” associated with the injections.
“While a recent medication warning from the United Kingdom recognized this risk, there are other studies citing no increased risk,” he said.
How safe are GLP-1s?“What this means for most people, is that if they do not stand to benefit significantly from GLP-1 medication the risks may very well exceed any potential benefits. For those without pre-existing pancreatic disease, GLP-1 medications are considered to have a favorable safety profile, with pancreatitis being rare and not definitively proven to increase in well-controlled trial data.”
— David Cutler, MD
Cutler said that for most people, the absolute risk of experiencing pancreatitis will be very low. However, he did single out a few factors that may contribute to increased risk.
“[P]atients with diabetes and obesity, which are the reasons for using GLP-1 medications often have existing risk factors for pancreatitis like gallstones, very high triglycerides, heavy alcohol use, or a history of pancreatitis. These factors must be taken into account when assessing the balance of benefits and risks for using GLP-1 medications,” he said.
Meanwhile, Perez underscored that pancreatitis is a rare side effect of GLP-1 drugs but that people should be aware of the signs.
“Most patients should be aware but not panicked because acute pancreatitis remains rare, just not vanishingly rare. We worry about it most in patients who also have gallstones, heavy alcohol use, hypertriglyceridemia, or pre-existing pancreatic disease,” he told us.
“For someone with metabolic syndrome who jumps on a GLP-1 and drinks heavily every weekend, that’s a different risk profile than someone with well-controlled diabetes, normal lipids, and no alcohol use,” Perez said.
Ali described the symptoms of pancreatitis to watch out for.
“The most common sign of pancreatitis is severe, persistent pain in the upper-middle abdomen that may radiate to the back. This is often accompanied by nausea and vomiting. As inflammation progresses, fever and chills may occur. If a patient experiences these symptoms, they should seek immediate medical attention,” he explained.
“Watch out for sudden, severe mid-epigastric pain that radiates to the back, pain that’s worse after eating or lying down, nausea or vomiting that doesn’t subside, and a tender or distended abdomen. Pain that doesn’t feel like typical [gastrointestinal] upset and is disproportionate to meals or exercise should be taken really seriously.”
— Hector Perez, MD
Perez also noted that GLP-1–associated pancreatitis may not always present with “textbook” symptoms.
“Some patients present with vague discomfort, bloating, or early satiety that doesn’t respond to antiemetics, and a high index of suspicion is what saves them from late diagnosis. Unfortunately, patients who get diagnosed often do when other things are ruled out, and by that time, they’ve been in a lot of pain,” he said.
Cutler urged patients to seek care promptly if they experience any symptoms such as severe abdominal or back pain, nausea and/or vomiting.
“While most cases [of pancreatitis] resolve with supportive care and discontinuation of the medication, pancreatitis can progress to a more serious condition,” Ali added.
Ali said that patients should receive all necessary information about potential side effects before starting the medication.
“While the most common side effects are gastrointestinal — such as nausea, vomiting, and diarrhea — serious complications like pancreatitis are much less frequent. To minimize risks, medications are started at a low dose and increased gradually. This advice remains the same whether the medication is used for diabetes or weight loss,” he said.
Cutler detailed some of the most common adverse reactions with GLP-1s:
“The most common reactions are nausea, vomiting, diarrhea, abdominal pain, constipation, and gastroesophageal reflux. Less common reactions associated with these medications are medullary thyroid cancer risk, severe allergic reactions, and pancreatitis.”
He added that, as is the case with any other medication, doctors and patients should weigh the risks against their benefits.
While acknowledging the benefits of GLP-1 drugs for weight loss, blood sugar management, and lowering cardiometabolic disease risk, Perez said people should be aware of a few lesser-known side effects.
“I’ve found out about lesser-known GLP-1 side effects directly from my patients, with a handful of them describing ‘debilitating brain fog,’ another symptom that is underdiscussed but existent. I’ve heard of people reporting ‘the worst upper stomach pain imaginable’ along with persistent nausea, thankfully not my own patients, and that’s exactly the symptom cluster we worry about with pancreatitis,” he said.
Both GLP-1 and GLP-1/GIP receptor agonists, which include dulaglutide, exenatide, liraglutide, semaglutide, and tirzepatide, have been linked to rare pancreatitis cases.
However, Ali said that the safety and side-effect profile may vary from person to person.
“Tirzepatide, which stimulates both GLP-1 and GIP receptors, appears to have fewer side effects; however, individual sensitivity varies,” he said.
“I believe we should neither demonize these medications nor minimize real harm signals. The MHRA update is simply a reminder that powerful drugs require powerful vigilance, and until we have larger, long-duration real-world safety data, clinicians should err on the side of specificity in monitoring and patients should be taught exactly what to look for.”
— Hector Perez, MD
