How GLP-1 Medications Work in the Gut
GLP-1 receptor agonists are a class of medications designed to mimic a naturally occurring hormone in the gut. It’s the key hormone that helps regulate blood sugar levels, and it also slows digestion and reduces hunger and appetite cues.
Semaglutide is sold under brand names you may be familiar with — Ozempic and Wegovy are key examples. Tirzepatide (Mounjaro, Zepbound) is a related drug that mimics the GLP-1 hormone and also targets GIP receptors (GIP is glucose-dependent insulinotropic polypeptide, another hormone involved in blood sugar regulation and appetite).
“These drugs slow gastric emptying, help people feel fuller longer, and can reduce overall food intake, which is why they may be effective for weight loss,” says Danielle Gaffen, RDN, the San Diego–based founder of Eat Well Crohn’s Colitis, which provides personalized nutrition counseling for people living with IBD and other digestive conditions.
While weight loss is part of the appeal of these medications, that can be complicated for people with UC. Weight in UC tends to be highly variable, Gaffen says.
Some people with UC struggle with unintentional weight loss during flares. But others may gain weight due to limited safe foods, reduced exercise because of symptoms, or medications that can increase appetite and cravings, like corticosteroids, Gaffen says. For them, GLP-1s may offer an additional tool for weight management that can be difficult to achieve through diet and exercise alone.
There’s also growing interest in how these medications may influence inflammation in the gut, which is a key driver of UC.
- A study published in 2023 found that GLP-1 medications may help reduce inflammation and strengthen the gut lining in people with UC, though it notes that most of the evidence so far comes from animal and lab-based studies, not large trials in people.
- A review published in 2025 in the Journal of Crohn’s and Colitis suggests that GLP-1 medications have both metabolic and anti-inflammatory benefits for people with IBD, with early studies linking them to improved outcomes like fewer hospitalizations.
- A large real-world study published in 2026 in the journal Inflammatory Bowel Diseases found that GLP-1 use in people with UC and Crohn’s disease was linked to lower rates of steroid use, hospitalization, and intestinal surgery. The researchers used the Mayo Clinic Platform, a healthcare database covering 8 million patients, to find about 580 people with IBD who had taken GLP-1 drugs. They note that their findings are observational and need confirmation in clinical trials.
Even with these promising results, the research has a long way to go, Moss says. “I’d call the data intriguing but not yet practice changing,” he says.
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