Does Wegovy Give You Diarrhoea?

Semaglutide, the active substance in Wegovy, works by activating GLP-1 receptors involved in appetite regulation. One well-documented effect of this mechanism is a slowing of gastric emptying — food moves through the digestive system more slowly than usual. While this contributes to the feeling of fullness many people experience, it can also unsettle the gut in various ways, including diarrhoea, constipation, nausea, indigestion, and heartburn.

Why some people get diarrhoea and others get constipation

Interestingly, Wegovy can cause both diarrhoea and constipation — sometimes at different points in the same person's journey. The gut's response to altered motility is individual: some people find things speed up, others find them slow down, and some cycle between the two. Neither pattern is unusual, and both are documented in the medicine's patient information.

When it tends to happen

Gastrointestinal symptoms are most commonly reported in the first few days after a new or increased dose. For many people, symptoms ease within one to two weeks as the body adjusts. They may return if the dose is increased again. Eating very fatty, rich, or large meals can also make gut symptoms more pronounced, which is why many people on GLP-1 medicines find smaller, lower-fat meals sit more comfortably.

Wegovy is a prescription-only medicine subject to additional monitoring. If you experience any side effects, you can report them to your healthcare professional and, if relevant to you, to your national reporting scheme — such as the UK's Yellow Card scheme — via the MHRA's Yellow Card service.

If you are curious how diarrhoea symptoms compare between semaglutide and tirzepatide, our guide to whether Mounjaro causes diarrhoea covers similar ground for that medicine. You may also find it useful to read about diarrhoea and Mounjaro in more detail, particularly if you are considering or have switched medicines. For a broader look at gastrointestinal and other side effects across GLP-1 treatments, the GLP-1 side effects hub is a good place to start.

One of the most practical things you can do when experiencing diarrhoea or any other digestive symptom on Wegovy is to log it consistently, so you can spot patterns and have a clear, detailed picture to share with your prescriber.

GLP Trackr's side-effect tracker lets you record symptoms — including diarrhoea, constipation, heartburn, nausea, and fatigue — each day, with notes on severity and timing. Over time, the app's insights surface patterns you might not notice otherwise: for example, whether symptoms are worse after certain meals, on dose-change days, or at a particular point in your weekly cycle. That kind of pattern data is genuinely useful to bring to a prescriber appointment rather than trying to recall it from memory.

The app's food logging feature — including an AI photo scan and barcode scanner — also makes it easy to track what you ate alongside how you felt, helping you identify whether specific foods are contributing to gut discomfort. Many people find that high-fat or high-fibre meals are harder on the stomach during the adjustment period, and seeing that connection in your own data can be clarifying.

You can also use the doctor report feature to pull together a summary of your symptoms, doses, and wellbeing for a prescriber conversation — no scrambling to remember when things were worst.

GLP Trackr is free to try for 7 days — download it on the App Store or Google Play and start building a picture of your own journey from day one.

Important: if diarrhoea is severe, persistent, or accompanied by symptoms that worry you — such as significant dehydration, abdominal pain, or blood in stools — contact your healthcare professional promptly. GLP Trackr helps you record what you are experiencing so you can discuss it with your prescriber; it is not a substitute for their advice. Any decisions about your dose or treatment should always be made with your prescriber, not on your own.

You might also find our page on headaches on GLP-1 medicines helpful if you are experiencing more than one side effect at once — a common experience in the early weeks.