Pharmacist warns of potential permanent gut damage from weight-loss injections

A growing cohort of patients using GLP-1 receptor agonist injections for weight loss and metabolic conditions report severe digestive problems, including gastroparesis, a condition in which the stomach moves too slowly or stops moving altogether. A pharmacist with more than three decades of experience says the problems, while not universal, are accumulating as these medications — among them Mounjaro — are prescribed at higher doses to maximize weight loss and improve glucose control. The drugs work by slowing gastric emptying, a mechanism that helps curb appetite but can become a source of chronic difficulty for some patients. Doctors and patients are increasingly seeking clarity on how often these side effects occur, how long they last, and what steps should be taken when symptoms emerge.

Daily Mail columnist Nadine Dorries publicly described severe heartburn within days of her first Mounjaro injection last June, after being prescribed the drug for pre-diabetes, fatty liver disease and high cholesterol. She stopped injections in January, but acid reflux worsened, and she later required an endoscopy. She was diagnosed with Barrett’s esophagus, a condition in which changes in the lining of the esophagus can raise the risk of cancer. Dorries is not alone; a growing number of patients on GLP-1 medications report reflux-like symptoms and other digestive complaints that prompt further medical evaluation. In the clinic, the same specialist notes that the standard response — increasing proton pump inhibitor (PPI) therapy — may help acid-related pain but does not address the underlying issue of delayed gastric emptying. Some patients experience persistent symptoms even after stopping treatment, a development that alarms clinicians who had hoped the problems would reverse.

Gastroparesis is a rare, chronic condition. In the United Kingdom, about 14 in every 100,000 people are diagnosed with it, with women twice as likely as men to be affected. The condition typically emerges in young adults, with the most common age range cited as 18 to 39, according to health charity Guts UK. In the United States, hundreds of patients have joined a multi-state class-action lawsuit against the makers of Mounjaro, Eli Lilly, and another GLP-1 drug, Ozempic, which is prescribed for diabetes but also used off-label for weight loss. Lawyers say more patients with gastroparesis and other severe side effects are expected to join as the litigation progresses. The suits accuse Eli Lilly and Novo Nordisk of failing to warn patients and physicians about certain adverse effects of these drugs; both companies say they will vigorously defend themselves against the claims.

One plaintiff described the personal impact: a 56-year-old woman diagnosed with gastroparesis who now faces the prospect of lifelong feeding via tube. The larger concern cited by clinicians is that the very mechanism that helps patients lose weight or improve metabolic markers can, for some, translate into long-lasting or even permanent digestive impairment. The consequences extend beyond discomfort. When the stomach empties slowly, people report early satiety, persistent nausea, vomiting, bloating and abdominal pain. The fear among practitioners is that prolonged symptoms lead to reduced nutritional intake and, in severe cases, malnutrition. The problem can also drive continued reliance on acid-suppressing medications, which, in the long term, carry their own risks.

From a medical perspective, GLP-1 therapies offer clear benefits for obesity and type 2 diabetes, including better cardiovascular outcomes and, in some patients, reduced risk-taking behaviors related to substance use. Yet the balance of benefit and risk becomes more complex as higher doses are used and as reports of gastroparesis and other gut-related side effects accumulate. Some patients observe that even after discontinuing the injections, digestion does not revert to baseline quickly, if at all. That reality underscores the need for careful patient selection, thorough counseling before starting therapy, and vigilant follow-up to detect early signs of delayed gastric emptying.

Health professionals emphasize that patients considering GLP-1 injections should receive full disclosure about potential digestive side effects, including the possibility of persistent symptoms. Clinicians are encouraged to monitor for new or worsening nausea, vomiting, bloating, early satiety and reflux, and to explore alternatives for people with a history of gastrointestinal issues. For patients who develop persistent symptoms, early referral to gastroenterology may help manage or mitigate the condition before it becomes chronic. While the therapies remain a valuable tool for obesity and metabolic disease, awareness of the risks is critical to informed decision-making and safe use.

As litigation unfolds and regulators continue to evaluate the safety profile of these medications, clinicians and patients alike are urged to maintain open communication and document any adverse experiences. In the meantime, the medical community stresses that not every patient will experience severe side effects, and GLP-1 therapies can be appropriate for many individuals when used with careful monitoring and individualized care plans. The conversations around these drugs will likely continue as more real-world data emerge and as legal claims advance, shaping how providers discuss risk, benefit, and alternatives with patients seeking weight loss or glucose control.