Ozempic, Wegovy and Zepbound: Why They Can Cause Diarrhea

Starting a new weight loss treatment can bring a lot of questions, especially about side effects. If you've noticed changes to your digestion since starting semaglutide, Ozempic, Wegovy, Mounjaro or Zepbound, you're not on your own. Diarrhea is one of the most common digestive side effects of these medicines, and there's a lot you can do to feel more comfortable while your body adjusts.

Article Summary:

• Diarrhea is a very common side effect of GLP-1 medicines like semaglutide, Ozempic, Wegovy, Mounjaro and Zepbound.
• It happens because these medicines change how quickly food moves through your digestive system.
• It's usually mild and short-lived, but you should get medical help if your symptoms are severe or don't improve.

Why do Ozempic, Wegovy and Zepbound cause diarrhea?

Ozempic, Wegovy, Mounjaro and Zepbound all belong to a group of medicines that work by mimicking a gut hormone. GLP-1 stands for glucagon-like peptide-1, a hormone your gut releases after you eat. These medicines mimic this hormone to help you feel full and to slow down stomach emptying. This slower gut motility is part of how these medicines support weight loss, but it can also lead to digestive side effects like diarrhea.[1]

In clinical studies, these are sometimes called gastrointestinal adverse events, or gastrointestinal adverse effects. This simply means side effects that affect your digestive system.[1]

Diarrhea is one of the most common of these gastrointestinal reactions.[1] It's most likely to happen in the first few weeks of treatment, or after your dose goes up. Your healthcare provider will usually start you on a low dose and may increase it over time, depending on side effect tolerability and rate of weight loss. This is called titration, and it gives your body time to adjust, which can help reduce side effects.

Ozempic and diarrhea

Ozempic contains semaglutide. It's licensed to treat type 2 diabetes, though some people are also prescribed it for weight loss. Because semaglutide slows down digestion, it can cause diarrhea, particularly when you first start treatment.[1]

Wegovy and diarrhea

Wegovy also contains semaglutide, at a higher dose than Ozempic, and it's licensed specifically for weight loss. It works in the same way, so it can lead to the same digestive side effects, including diarrhea.[1]

Zepbound and diarrhea

Zepbound contains a different active ingredient called tirzepatide. Instead of mimicking one gut hormone, it copies two: GLP-1 and a second hormone called GIP. This dual action can make Zepbound very effective for weight loss, but it can also cause diarrhea and other digestive side effects, in a similar way to Ozempic and Wegovy.

Other common side effects

Diarrhea isn't the only digestive side effect linked to these medicines. Nausea, vomiting, constipation, bloating and wind are also common gastrointestinal disturbances.[1] Research shows this happens to a lot of people when they start treatment or increase their dose.[2] The good news is these adverse events are usually mild and don't last long.

Rarer risks to know about

Most digestive side effects are mild, but it's worth knowing about a few rarer risks.

• Kidney problems. Ongoing diarrhea or vomiting can lead to dehydration, which can affect your kidney function.
• Gallbladder issues. Losing weight quickly can increase your risk of gallbladder issues, such as gallstones. If you get sudden pain in the upper middle or right side of your stomach, your right mid back or shoulder, please seek medical attention. Pain may also spread to your right upper back or shoulder blade area. When gallstones block a bile duct, you may have pain with fever and chills.

When to get medical help

Diarrhea is usually mild and goes away on its own. But you should get medical advice if you have:

• signs of severe dehydration, like feeling more thirsty than usual, dark urine, going to the toilet less often, tiredness or feeling light-headed
• Yellow skin
• diarrhea that lasts more than two days
• severe stomach pain
• a high fever, above 38°C (100.4°F)
• blood in your stool

If you get severe, ongoing pain in your stomach that spreads to your back, this could be a sign of pancreatitis, which is inflammation of your pancreas. It may also occur alongside vomiting. If this happens, stop taking your treatment and get urgent medical help right away by calling 911.

How to manage digestive side effects at home

Small lifestyle adjustments can help you feel more comfortable while your body adjusts to treatment.

• Hydration tips. Diarrhea can lead to dehydration, so drink plenty of clear fluids.[3] Water, herbal teas, oral rehydration solutions and electrolyte solutions can all help.
• Make dietary adjustments. Certain dietary factors can make diarrhea worse, including fatty foods, sugary foods, caffeine intake and dairy products.[4] Keeping a food diary can help you spot your triggers.
• Eat smaller meals. Smaller, more frequent meals can be easier to manage while your body adjusts.
• Ask about over-the-counter medications. Some over-the-counter anti-diarrhea medications may be suitable, but check with your healthcare provider before you take anything new.
• Get enough rest. Give your body a chance to recover. Experts recommend seven to nine hours of sleep a night to support your health.[5]

Diarrhea and other digestive side effects are common with semaglutide, Ozempic, Wegovy, Mounjaro and Zepbound and similar medicines. They're usually part of your body adjusting, and they tend to settle down within a few days. These treatments work best alongside a low-calorie diet and regular physical activity, not on their own. If you have any concerns about your side effects, talk to your healthcare provider.

Find out what treatment could be right for you with MedExpress.

References

1. Ismaiel A, Scarlata GGM, Boitos I, Leucuta DC, Popa SL, Al Srouji N, et al. Gastrointestinal adverse events associated with GLP-1 RA in non-diabetic patients with overweight or obesity: a systematic review and network meta-analysis. International Journal of Obesity. 2025 Aug 13.
2. Gorgojo-Martínez JJ, Mezquita-Raya P, Carretero-Gómez J, Castro A, Cebrián-Cuenca A, de Torres-Sánchez A, et al. Clinical recommendations to manage gastrointestinal adverse events in patients treated with GLP-1 receptor agonists: a multidisciplinary expert consensus. Journal of Clinical Medicine.
3. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of diarrhea [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases; 2019.
4. Canadian Digestive Health Foundation. Diarrhea [Internet]. Canadian Digestive Health Foundation; 2025.
5. Government of Canada, Statistics Canada. Catching zzz's on World Sleep Day [Internet].