A British mother has revealed how her dramatic weight-loss journey took a terrifying turn after one of her organs began “rotting”- a complication she says was linked to the popular diabetes and weight-loss drug Mounjaro.Emma McDonald, 38, turned to Mounjaro after struggling to lose weight gained during pregnancy. Following the birth of her daughter, her weight increased from 15st (95.2kg) and a size 12 to 21st (133.3kg) and a size 24. She was also told that the drug might help manage her polycystic ovary syndrome (PCOS) symptoms, including irregular periods. “Mounjaro was my last resort,” Emma told LADbible. “I had a massive weight gain after giving birth and my PCOS made it difficult to lose it.”Within weeks of starting the GLP-1 drug in June 2024, Emma began noticing results. “When my work clothes stopped fitting, that was my wake-up call,” she said. “I started Mounjaro in June 2024 – within the year I lost 8st.”However, only two months into the treatment, Emma began experiencing “excruciating” indigestion pain. Initially, she blamed the discomfort on an increased dosage of the medication, but the truth was far more serious.After a visit to her GP, an ultrasound revealed a gallstone blocking her bile duct and a condition known as cholecystitis, an inflammation of the gallbladder. The diagnosis explained her persistent “stinging” rib pain and the need for hot showers to relieve it.She recalled, “By this point, I was about 19st. I cracked on with the recovery period, it was painful and I had four holes in my stomach.”In October 2025, doctors discovered that her gallbladder had started ‘rotting’, prompting an urgent cholecystectomy (surgical removal of the organ).“I was told my gallbladder had gone rotten and Mounjaro was an exacerbating factor, but overall, I’m much healthier now so I don’t have any regrets,” she said.
What doctors say about gallbladder risks
Drugs like Mounjaro and Ozempic belong to a class known as GLP-1 receptor agonists, which slow digestion and suppress appetite by making the stomach feel full for longer. While highly effective for weight loss, they have also been associated with gallbladder complications in some patients.According to the National Institutes of Health (NIH), women are two to three times more likely to develop cholecystitis than men. Risk factors include birth control use, childbirth, and rapid weight loss, all of which applied in Emma’s case.“It was a perfect storm of having PCOS, a massive weight gain after giving birth and using Mounjaro,” Emma said. “But I don’t have any regrets, Mounjaro has helped me take control of my life.”Since her surgery, Emma continues to take 7.5mg doses of Mounjaro, maintaining a weight of 12st 9lbs (80.2kg) and a size 12. She admits recovery has been challenging: “I’m transitioning back into eating more food now, I’ve been finding meat really hard to digest since the operation.”In a statement to LADbible, an Eli Lilly spokesperson said: “Patient safety is Lilly’s top priority. We take any reports regarding patient safety extremely seriously and actively monitor, evaluate, and report safety information for all our medicines.The Mounjaro (tirzepatide) Patient Information Leaflet warns that gallstones is a common side effect when used for weight management, and an uncommon side effect when used for type 2 diabetes. We encourage patients to consult their doctor or other healthcare professional regarding any side effects they may be experiencing and to ensure that they are getting genuine Lilly medicine.”
