Mounjaro, Wegovy and Ozempic linked to pancreatic inflammation. But new drugs are on the way

Originally written on 7 July 2025, updated on 27 February 2026

Orforglipron appears to be as effective as a weekly Ozempic injection in inducing weight loss and lowering blood glucose levels. It is just one of more than a dozen experimental drugs whose data researchers are expected to present.

Some of these drugs are still in the early stages of development, while others could reach the market as early as next year. Among them are treatments that may lead to greater weight loss than the 15–20% of body weight typically achieved with current medications. They may also be easier to take than weekly injections and help patients lose weight without excessive loss of muscle mass.

Greater competition — and, in the case of oral formulations, lower production costs — could ultimately mean lower prices for patients.

“Many people say, ‘Oh, we have Ozempic, everything is fine now,’” said Megan Capozzi, Associate Research Professor at Washington University School of Medicine, who studies diabetes and obesity treatments. “But I think there is still a great deal of room for improvement.”

According to some estimates, one in eight adults in the United States has already taken a drug such as Wegovy or Zepbound. Researchers believe that many more people would use — and continue using — weight-loss medications if they did not require weekly injections.

Put simply, Dr Capozzi noted, “people prefer taking pills to injections.”

That is why physicians and investors are particularly enthusiastic about Orforglipron. Like Ozempic and other drugs currently on the market, Orforglipron mimics a hormone that regulates blood sugar and suppresses appetite. In data presented at a conference, researchers following more than 500 patients with type 2 diabetes reported that those taking the highest dose lost an average of approximately 7.5 kilograms after nine months. Around two-thirds of participants also saw their blood glucose levels fall into the target range.

Weight-loss and diabetes injections linked to potentially fatal side effects

New data from the UK Medicines and Healthcare products Regulatory Agency (MHRA) show that the class of drugs including Mounjaro, Wegovy and Ozempic may be associated with pancreatic inflammation.

According to the UK regulator, more than one million people in the United Kingdom have used these diabetes and weight-loss injections, which have been linked to a potentially serious side effect, with some reported deaths.

The MHRA reports 181 cases of acute or chronic pancreatitis associated with Mounjaro, including five deaths. Wegovy and Ozempic have been linked to 113 cases of pancreatitis and one death. Other, less widely used GLP-1 drugs have also been associated with cases and fatalities.

There is no evidence that the medications directly caused the deaths, and the available data are not strong enough for the MHRA to restrict access to them.

Pancreatitis also occurs in individuals who do not take GLP-1 drugs, with approximately 560 cases per million people annually in the general population. Gallstones and alcohol are the primary causes.

Individuals who reported pancreatitis via the MHRA’s Yellow Card reporting system while using the medication will be asked to provide saliva samples for genetic testing.

“It felt like someone had just stabbed me”

Lorna Edgar, from Lancashire, developed acute pancreatitis, underwent gallbladder removal and now lives with chronic health problems. She told Sky News that she believes her condition was a side effect of Saxenda, another GLP-1 weight-loss drug in the same class as Wegovy and Ozempic.

“I was in excruciating pain, crying, sweating, shaking… I just had tears running down my face. Then the ambulance arrived and I was rushed to hospital,” she said.

Ms Edgar legally purchased the injections through an online pharmacy after her GP determined that her BMI was not high enough to qualify for treatment through the National Health Service. She said her weight had affected her self-esteem: “It made me feel unattractive. I just desperately wanted to lose weight.”

She described Saxenda as “very easy to obtain.” Within days of completing an online form, she received a repeat prescription and began injecting the drug at a cost of about £200 per month.

“My appetite completely disappeared. The weight dropped off. I was very pleased with the results and had no side effects. I felt great.”

However, about five weeks after starting the injections, she woke up with severe abdominal pain. “When I went to the bathroom, I was in agony. I had a fever. I was doubled over with stomach pain. It felt like someone had just stabbed me in the stomach.”

She spent five days in hospital, receiving painkillers and intravenous treatment. Following acute pancreatitis and months of medical care, including gallbladder removal, she says she developed irritable bowel syndrome (IBS) and other digestive problems.

“It has caused long-term health problems, worse than being overweight or obese… every day I am reminded of what those injections did to my health, my digestive system and my gut. It’s simply awful.”

There is no proven direct link between Ms Edgar’s experience and Saxenda. Novo Nordisk UK stated that side effects are possible with any medication.

Professor Matt Brown, Chief Scientific Officer at Genomics England, commented:
“GLP-1 medicines such as Ozempic and Wegovy have made headlines, but like all medicines they carry the risk of serious side effects.

“We believe there is real potential to minimise such adverse effects, as many of these reactions have a genetic basis.

“This next phase of our partnership with the MHRA will generate data and evidence to support safer and more effective treatments through more personalised prescribing.”

The main symptoms of pancreatitis are severe central abdominal pain, fever and nausea. Acute cases are treated in hospital with fluids and oxygen and generally resolve within a few days. Complications can occur, and approximately 5% of acute cases are fatal.

As with all medications, there is a balance between risks and benefits.

For people with type 2 diabetes or obesity, the injections offer clear benefits: lowering blood sugar levels, promoting rapid weight loss and reducing cardiovascular mortality by around 20%.

However, for individuals who are only slightly overweight and purchase injections privately to lose a few kilograms before summer holidays, the health benefits are far less clear. For them, this serves as a warning.

These are powerful drugs that act not only on appetite but on multiple organs, including the brain.

Patients are advised to take these medications only for approved indications and under the close supervision of a healthcare professional, who can provide information about potential side effects.

One documented side effect is possible dysesthesia.