Mounjaro and Diverticulitis: What People on Tirzepatide Should Know

Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist taken as a once-weekly injection. One of its well-documented effects is slowing the rate at which the stomach empties — a mechanism that contributes to the reduced appetite many people experience. This slower transit can have knock-on effects throughout the digestive system.

Diverticulitis occurs when small pouches (diverticula) that form in the wall of the colon become inflamed or infected. Changes in bowel habits — whether constipation or diarrhoea — are among the most commonly reported gastrointestinal side effects of tirzepatide, and both can be relevant for people with diverticular disease. Constipation in particular may increase pressure within the colon, which is thought to be a contributing factor in diverticular flares.

Commonly reported bowel-related side effects of Mounjaro

• Constipation — reported by a significant proportion of users, particularly during dose increases
• Diarrhoea — also common, especially in the earlier weeks
• Nausea and reduced appetite, which can affect food and fluid intake
• Bloating and indigestion

If you have a history of diverticulitis and notice changes in your bowel habits after starting or increasing Mounjaro, it is worth keeping a clear record of what you are experiencing. According to NHS guidance, people with diverticular disease are generally advised to maintain adequate fibre and fluid intake — factors that can be disrupted when appetite drops significantly on a GLP-1 medicine.

This is not a reason to stop or change your medication without speaking to your prescriber first. Any concerns about how Mounjaro may be interacting with your digestive health should be raised with your healthcare professional promptly. People managing other conditions alongside tirzepatide — such as those exploring Mounjaro alongside endometriosis — often find that careful symptom tracking helps them have more productive conversations with their care team. It is also worth being aware that some other medications used alongside Mounjaro may affect gut function; for example, see general information on codeine and Mounjaro, since opioids are known to slow gut motility and can compound constipation.

For a broader overview of what Mounjaro is and how it works, visit the Mounjaro information hub.

When you are managing an underlying condition like diverticular disease alongside a GLP-1 medicine, detailed symptom records can be genuinely useful — both for spotting your own patterns and for informing your prescriber appointments.

GLP Trackr's side-effect and symptom tracking feature lets you log digestive symptoms — such as constipation, bloating, or changes in bowel habits — against your dose log and daily check-in data. Over time, this can reveal whether symptoms cluster around injection day, after certain foods, or during dose increases. That kind of personal record is far more useful to bring to a prescriber than a vague recollection.

The daily check-in also lets you log water intake and food, which is relevant here: staying hydrated and maintaining fibre intake are practical considerations your healthcare team may discuss with you in the context of diverticular health. If your appetite has dropped significantly on tirzepatide — as many people find — tracking what you are actually eating and drinking helps ensure you are not inadvertently falling short on fluids or dietary fibre without realising it.

GLP Trackr can also generate a summary report of your logged symptoms and trends, which you can bring to an appointment rather than starting from scratch each time.

Important: If you experience severe abdominal pain, fever, or symptoms that feel unusual or alarming, contact your healthcare professional promptly rather than waiting. GLP Trackr helps you record information to discuss with your prescriber — it does not replace their guidance, and it is not a diagnostic tool. Any decisions about whether Mounjaro is appropriate for you given your diverticular history are for your prescriber to make, not for you to navigate alone.

Start logging your symptoms and daily patterns with GLP Trackr — available free on the App Store and Google Play, with a 7-day free trial to explore everything the app offers.