Mounjaro Diarrhoea: Tips for Quick Relief

Summary Box

• Mounjaro may cause diarrhoea because it slows down digestion.
• Stay hydrated, drink plenty of water.
• Choose a light diet with easy to digest foods.
• Over-the-counter medicines may help.
• If your diarrhoea lasts for a long time, consult a doctor.

 

Introduction

Mounjaro is becoming popular in the UK for weight loss. It was first approved to treat type 2 diabetes, but people use it now to help manage their weight. Patients often notice weight loss within a few months, along with managed blood sugar level and appetite regulation.

The most common side effect of Mounjaro is diarrhoea. This is usually short-term but can feel uncomfortable. Some people get it in the first few weeks, while others notice it after the dose increases. What is good about it is, there are ways to make it easier to manage.

Related read: Mounjaro Side Effects: What Every Patient Should Know

 

Understanding Mounjaro Diarrhoea

Mounjaro diarrhoea is part of gastrointestinal (GI) issues that can also include nausea, vomiting, bloating, constipation, and indigestion. These happen because Mounjaro changes how food moves through your GI tract.

Common signs of diarrhoea on Mounjari include:

• Loose or water stools
• Going to the toilet more frequently
• Stomach cramps
• Feeling tired or fatigued after using the toilet

Although nausea and constipation are common, many find diarrhoea more uncomfortable because of its urgency. The positive side is that, unlike constipation, diarrhoea usually settles down more quickly after your body adjusts to Mounjaro.

Related read: Is Mounjaro Safe? Expert Insights & UK Patient

 

Why Does Mounjaro Cause Diarrhoea?

The reason Mounjaro causes diarrhoea is because of how it works in the body.

• Hormone effects: Mounjaro copies the GLP-1 and GIP hormones that help control blood sugar, slow digestion and reduce appetite.
• Slower gastric emptying: When food remains for a longer period in your stomach, it makes you feel full and sometimes upset stomach.
• Bowel reaction: The gut may respond by moving food through more quickly, which can cause diarrhoea.
• Gut bacteria changes: Some studies suggest these types of medicine may briefly change the balance of gut bacteria, that may add to the symptoms.

In short, because of the changes on how you digestive system works, Mounjaro can trigger diarrhoea, and for most people, the condition improves after a few weeks as the body adjusts.

Want tips on gentle foods that help digestion? See our guide: What to Eat on Mounjaro.

 

How Common Is It?

Study shows that diarrhoea is one of the most common side effects of Mounjaro.

• In a large weight loss trial, (SURMOUNT-1 trial) 12-18% of individuals had diarrhoea.
• Nausea and constipation are also common, but diarrhoea was one of the top digestive issues.
• No serious cases were reported, only mild to moderate.

Having diarrhoea on Mounjaro is almost never an urgent matter. Most people will start feeling better within days or weeks, especially by following easy tips to help the digestion process.

 

Managing Mounjaro Diarrhoea

There are many simple tips to help diarrhoea tolerable on Mounjaro.

 

Stay hydrated

Diarrhoea can make you dehydrated and lose minerals, keeping yourself hydrated is the first and most important step.

Tips to try:

• Sip water every hour, rather than big amounts all at once.
• For frequent diarrhoea, you can try oral rehydration salts.
• Diluted sugar-free sports beverages will help replace lost electrolytes.
• Herbal teas such as chamomile and peppermint could help soothe the stomach.

Look out for signs of dehydration which could include dizziness, dark urine, tiredness, or a dry mouth. Consider replacing fluids immediately.

Further reading: Mounjaro Dosage Chart: Weekly Dosing Guide for Weight Loss & Diabetes

 

Dietary Adjustments

Food has a large part to play while managing diarrhoea. Small adjustments can soothe your stomach and help your gut adjust.

• Go on a BRAT diet. Bananas, rice, applesauce, and toast are gentle on the stomach.
• Eat small but frequent, smaller meals digest more easily.
• Avoid fatty, spicy, or fried foods, it can make your diarrhoea worse.
• Temporarily stop eating fibre-rich foods until diarrhoea resolves.
• Choose proteins like chicken, fish, or eggs that can soothe digestion.

When your stool begins to normalise, reintroduce fibre to maintain a healthy gut.

For meal ideas, see our guide: What to Eat on Mounjaro: 10 Healthy Choices

 

Over-the-Counter (OTC) Solutions

If you want a quick relief, here are some non-prescription medications and supplements you might consider buying:

• Loperamide: Slows down the diarrhoea and delays going to the toilet.
• Activated charcoal: It can provide relief from gas and bloating.
• Probiotics: Help restore healthy gut bacteria, especially if you have had diarrhoea often.

Always check with your doctor before using any of these, especially if you have already taken other medicines.

 

Sulphur Burps and Diarrhoea: A Hidden Connection

Others taking Mounjaro experience sulphur burps and diarrhoea at the same time.

• What are sulphur burps? These are burps that smell like rotten eggs, due to a gas called hydrogen sulphide.
• Why do they happen? As the digestive process slows, food can sit in the stomach longer and start to ferment, creating the smell.
• Why with diarrhoea?When they occur together, it may be due to food sensitivities or a stronger digestive reaction to Mounjaro.

 

How to manage sulphur burps and diarrhoea

• Avoid foods that are high in sulphur, like onions, garlic, broccoli, and eggs.
• Sip ginger tea or lemon water
• Try probiotics to support gut health
• Eat slowly and chew food well to decrease the amount of gas.

 

Verified Before & After

Verified Before & After

 

When to Seek Medical Advice

Diarrhoea from Mounjaro usually improves within a few days. But you should contact your GP or healthcare provider if you have:

• Diarrhoea that persist longer than 7 days.
• Signs of severe dehydration like dizziness, rapid heartbeat, fainting.
• Blood in your stools, or black tar-like stools
• Strong stomach cramps and pain
• Symptoms that suddenly get worse after improving.

Also keep in mind, alcohol and some medicines can make stomach side effects worse.

For more details, see our guide on Mounjaro and Alcohol: Safe Drinking Practices Explained

 

Conclusion and Final Tips

Mounjaro works very well for weight loss and blood sugar control, but diarrhoea is a common side effect, especially at the start. The good news is that most people can manage it with simple steps.

Key takeaways:

• Diarrhoea happens because Mounjaro slows digestion and changes how the gut works.
• Drink plenty of fluids to prevent dehydration.
• Follow a gentle diet, such as the BRAT diet, to calm your stomach.
• Probiotics and some over the counter medicines may help, but always check with your GP first.
• If side effects are severe or do not go away, seek medical advice.

Most importantly, diarrhoea is usually temporary. For many patients, it improves within a few weeks, making it easier to stay on treatment with confidence.

 

FAQs

• Can Mounjaro diarrhoea be prevented?

Not fully, but starting with the lowest dose, eating smaller meals, and drinking enough fluids can help lower the risk.

• How long does diarrhoea usually last?

Most people feel better within a few days to a few weeks as their body gets used to the medicine.

• Are sulphur burps linked to diarrhoea?

Yes both can happen because digestion slows down and food ferments in the gut.

• Is it safe to use anti-diarrhoea medicine with Mounjaro?

Sometimes, over the counter medicines like loperamide can help, but only if your doctor says it is safe for you.

• When should I see a doctor about diarrhoea?

If it lasts more than a week, causes dehydration, or you notice blood in your stools, contact your GP.