Diarrhoea on Wegovy: What to Expect and How to Manage It

Wegovy contains semaglutide, a GLP-1 receptor agonist. One of the ways GLP-1 receptor agonists work is by slowing gastric emptying — the rate at which food moves from the stomach into the small intestine. While this effect contributes to a greater sense of fullness, it can also disrupt the normal rhythm of the digestive system, leading to symptoms such as nausea, constipation, or, in some people, diarrhoea.

When is it most likely to happen?

Diarrhoea is most commonly reported in the first few days after starting Wegovy or after moving to a higher dose. According to information in the electronic Medicines Compendium (eMC), gastrointestinal side effects are among the most frequently listed adverse reactions for semaglutide. For most people, symptoms ease as the body acclimatises — though the timeline varies from person to person.

At the higher 2.4 mg maintenance dose, some people notice gastrointestinal symptoms returning temporarily, even if earlier doses were well tolerated. This is a commonly reported pattern rather than a sign that something has gone wrong, but it is always worth mentioning to your prescriber or doctor if it is affecting your daily life.

When should you contact a healthcare professional?

Mild, short-lived diarrhoea is generally considered a known side effect. However, you should contact your healthcare professional promptly if diarrhoea is severe, persistent (lasting more than a few days), accompanied by significant dehydration, or if you notice any other concerning symptoms alongside it. Never try to self-manage serious or ongoing symptoms without professional guidance.

If you are also taking medicines for diabetes or other conditions, speak to your prescriber or doctor about how diarrhoea could affect their absorption or your overall management. For related gut side effects that can overlap with this experience, it is worth reading about diarrhoea on tirzepatide (Mounjaro) and how diarrhoea patterns compare across GLP-1 medicines — the underlying mechanisms share similarities. You can also explore foods to avoid when experiencing diarrhoea on Wegovy for practical dietary context.

One of the most useful things you can do when a side effect like diarrhoea appears is record it consistently — not to treat it yourself, but to build a clear picture to share with your prescriber or doctor.

GLP Trackr's side-effect tracker lets you log gut symptoms each day, noting severity and timing alongside your dose schedule. Over days and weeks this creates a timeline that can reveal whether symptoms cluster around injection day, improve with dietary changes, or ease at a particular point in your titration. That kind of structured record is far more useful to bring to an appointment than trying to recall how things felt several weeks ago.

The app's daily check-in also captures energy levels, mood, and food intake alongside symptoms, so you can see the full picture of how your body is responding — not just a single data point in isolation. If you want to understand how what you eat on injection days might be affecting your gut, the food logging feature (including AI photo scan and barcode) makes it straightforward to keep a record without adding to the burden of an already uncomfortable day.

GLP Trackr is a tracking and journaling tool — it does not replace the advice of your prescriber or doctor, and any decision about how to manage a side effect or adjust your treatment belongs with them. If symptoms are severe or persistent, please contact your healthcare professional promptly rather than waiting for a scheduled appointment. You can also report side effects to your national scheme for monitoring medicines (such as the UK's Yellow Card scheme or the equivalent body in your country).

For a broader overview of what to expect on semaglutide, the GLP-1 side effects hub covers the full range of commonly reported symptoms across both Mounjaro and Wegovy.

Start logging your symptoms and spotting your own patterns — GLP Trackr is available free on the App Store and Google Play, with a 7-day trial so you can see whether it works for you before committing.