Some people taking glucagon-like peptide 1 (GLP-1) receptor agonists — a type of medication used to support weight loss and manage type 2 diabetes — experience gastrointestinal (GI) side effects, including diarrhea. This is one of the most common side effects of GLP-1 medications, along with nausea, vomiting, and stomach discomfort or abdominal pain.

If you’re living with this side effect, talk with your doctor or pharmacist. They can help you find ways to manage diarrhea while continuing your treatment. Here’s what to know about GLP-1 receptor agonists and digestive issues.

How Do GLP-1 Drugs Cause Diarrhea?

GLP-1 medications may lead to diarrhea in a couple of ways. Diarrhea — frequent, loose, or watery bowel movements — can be more than just uncomfortable or inconvenient. It may cause dehydration, nutrient loss, and fatigue, especially if it continues over time. In some cases, severe or long-lasting diarrhea can interfere with daily life and overall health. That’s why it’s important to understand why this happens and how to manage it.

First, though, it helps to understand how these medications work in your body.

How Do GLP-1 Drugs Work?

GLP-1 is a hormone your body makes naturally. It plays a role in digestion, blood sugar control, and appetite regulation.

GLP-1 receptor agonists are medications that mimic this hormone. When you take a GLP-1 drug, it activates the same hormone receptors in your body. This action tells your body to:

• Release insulin (a hormone that lowers blood sugar)
• Slow down stomach emptying
• Reduce appetite

These combined effects help lower blood glucose levels and support weight loss, which is why GLP-1 receptor agonists are used to treat type 2 diabetes and obesity.

GLP-1 Drugs and Diarrhea

Health experts don’t know exactly why GLP-1 receptor agonists sometimes cause diarrhea, but they believe a couple of processes may be involved. One is that GLP-1 medications slow down the movement of your GI tract. This change in how your gut works can lead to diarrhea in some people and constipation in others.

Another theory is that these drugs influence certain pathways in your brain and nervous system that also affect your digestive system. This brain-gut connection may help explain why some people experience diarrhea with GLP-1 medications.

Some GLP-1 drugs appear more likely to cause gastrointestinal side effects than others. Earlier studies suggest that semaglutide (sold as Ozempic, Wegovy, and Rybelsus) may cause more digestive issues, including diarrhea, than older GLP-1 medications like liraglutide (Saxenda and Victoza). However, newer drugs like tirzepatide (Mounjaro or Zepbound) appear to have similar rates of gastrointestinal side effects compared to semaglutide. Ongoing research is evaluating whether future GLP-1 medications may reduce these effects.

Diarrhea may also occur because some GLP-1 drugs have a longer half-life — meaning they stay in your system longer. This extended exposure might increase the chance of side effects.

In addition, different GLP-1 medications affect the digestive system at different times. Some act quickly, while others take longer to produce an effect. Starting at a lower dose and increasing gradually can help reduce GI side effects, including diarrhea. You’re most likely to notice these effects when starting a new medication or moving to a higher dose.

Other Possible Causes of Diarrhea in People Taking GLP-1 Drugs

Even if you’re taking a GLP-1 medication, that may not be the only reason — or even the main reason — you’re experiencing diarrhea. Other causes could be at play, especially if you’ve been on the same dose for a while and are just now noticing this symptom.

Diarrhea can have a lot of different causes, including:

• Infections (such as a stomach virus)
• Other medications, such as metformin
• Food poisoning
• Food intolerances or sensitivities
• Digestive conditions, like gastroesophageal reflux disease (GERD)
• Recent medical procedures that may affect your digestive system

Some causes may be easy to spot — for example, if you recently had a procedure. Others, like a food sensitivity or an undiagnosed condition, may be harder to identify. That’s why it’s a good idea to talk to your doctor. They can help figure out what’s causing your symptoms and suggest the right steps for relief.

Treating Diarrhea Connected to GLP-1 Drugs

There are several ways to manage diarrhea and other digestive side effects from GLP-1 medications. The right approach often depends on how severe your symptoms are. Mild to moderate symptoms can usually be treated with simple changes, while more serious or long-lasting diarrhea may need medical treatment.

Managing Mild to Moderate Diarrhea

If you’re experiencing mild or moderate diarrhea — especially after starting or increasing the dose of a GLP-1 medication — it’s important to talk to your healthcare provider or pharmacist. They can help you manage your symptoms and monitor for complications if things don’t improve.

Your doctor will likely talk to you about making some lifestyle changes, mostly to how you eat. They may include:

• Eating smaller, more frequent meals
• Avoiding getting overly full
• Staying away from certain foods that seem to trigger your symptoms
• Skipping alcohol and carbonated drinks
• Drinking plenty of fluids to stay hydrated

If your diarrhea lasts more than a few days, your doctor might recommend an over-the-counter antidiarrheal medication. In some cases, they may prescribe a medication or suggest a probiotic or supplement to help rebalance your digestive system.

Dealing With Severe or Persistent Diarrhea

If your diarrhea doesn’t go away or starts getting worse, it’s time to talk with your doctor about next steps. Most healthcare providers don’t recommend using antidiarrheal medications long-term. Instead, they’ll help you find other ways to manage the problem.

This may involve adjusting your GLP-1 medication. You might pause dose increases, return to a lower dose, or try switching to a different medication altogether.

Your doctor may also want to double-check whether the GLP-1 medication is really the cause of your diarrhea. If they find another reason — such as a digestive condition, food sensitivity, or another medication — they can help treat that issue so you can continue using your GLP-1 treatment safely.

In some cases, GLP-1 medications may not be a good fit. If you and your doctor find that none of them work for you without causing severe or long-lasting diarrhea, you may decide together to stop treatment and try another type of weight management medication.

Talk With Others Who Understand

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