Sulphur Burps, Nausea & Vomiting on Mounjaro: Causes and Solutions

Mounjaro has quickly become one of the most effective medications for weight loss and type 2 diabetes. However, like all GLP 1 based treatments, it can cause gastrointestinal side effects, particularly during the early stages of treatment or dose increases.

One symptom that often surprises patients is sulphur burps. These are burps with a strong egg like smell, sometimes accompanied by nausea, bloating or vomiting. While unpleasant, they are usually harmless and manageable.

This article explains why sulphur burps can occur on Mounjaro, what other stomach related side effects you might experience, and what you can do to reduce or prevent them.

What is Mounjaro and how does it affect digestion?

Mounjaro contains tirzepatide, a dual GIP and GLP 1 receptor agonist. It works by:

Reducing appetite

Increasing feelings of fullness

Slowing stomach emptying

Improving blood sugar control

The slowing of gastric emptying is one of the main reasons Mounjaro is so effective for weight loss. However, it is also the reason gastrointestinal side effects can occur.

When food stays in the stomach for longer, it has more time to ferment. This can lead to gas production, bloating, nausea and in some cases sulphur burps.

What are sulphur burps?

Sulphur burps are burps that smell like rotten eggs. The smell comes from hydrogen sulphide gas, which is produced when certain foods are broken down by bacteria in the gut.

This gas can build up when digestion slows down. Because Mounjaro delays gastric emptying, food can sit in the stomach for longer than usual, increasing the chance of fermentation and gas production.

Sulphur burps are not dangerous, but they can be uncomfortable and socially awkward.

Why does Mounjaro cause sulphur burps?

There are several reasons why sulphur burps may occur while taking Mounjaro.

Slower stomach emptying

Mounjaro intentionally slows digestion. This allows food to ferment for longer, increasing hydrogen sulphide gas production.

Changes in gut bacteria

GLP 1 medications can temporarily alter the balance of gut bacteria. This can change how food is broken down and increase gas production.

Diet related triggers

Certain foods are more likely to cause sulphur gas, especially when digestion is slowed. These include:

Eggs

Red meat

Onions and garlic

Cruciferous vegetables such as broccoli and cauliflower

High fat or greasy foods

Dose escalation

Sulphur burps are more common when starting Mounjaro or moving up to a higher dose. The digestive system often needs time to adapt.

Nausea and vomiting on Mounjaro

Nausea is one of the most common side effects of Mounjaro. Vomiting can occur but is less common and usually happens early in treatment or after a dose increase.

These symptoms are caused by:

Slower gastric emptying

Effects on the brain’s appetite and nausea centres

Eating too quickly or eating large meals

In most people, nausea improves within a few weeks as the body adjusts.

When should you be concerned?

In most cases, sulphur burps, nausea and mild vomiting are temporary and improve over time.

You should speak to your clinician if:

Vomiting is persistent or severe

You cannot keep fluids down

You experience signs of dehydration

Abdominal pain is severe or worsening

Symptoms do not improve after several weeks

Very rarely, severe vomiting may require dose adjustment or temporary treatment interruption.

Practical ways to reduce sulphur burps and nausea

Eat smaller, slower meals

Large meals are harder to digest when gastric emptying is slowed. Smaller portions reduce fermentation and gas buildup.

Avoid trigger foods

Temporarily reducing sulphur rich foods such as eggs, red meat and cruciferous vegetables can help.

Limit fatty and greasy foods

High fat meals stay in the stomach longer and often worsen nausea and burping.

Stay well hydrated

Sip water regularly throughout the day. Dehydration can worsen nausea.

Do not lie down after eating

Remaining upright for at least two hours after meals can help digestion and reduce reflux and burping.

Review your dose escalation

If symptoms started after a dose increase, slowing down the titration schedule may help. This should always be discussed with your prescriber.

Consider meal timing

Some people find symptoms are worse in the evening. Having your main meal earlier in the day may reduce overnight symptoms.

Can medication help?

In some cases, short term treatments may be useful, such as:

Antacids

Acid reducing medications

Anti nausea medication

These should only be used under guidance from a healthcare professional. Over the counter remedies may provide temporary relief but do not address the underlying cause.

Will these side effects go away?

For most people, yes.

Sulphur burps, nausea and vomiting are most common:

In the first few weeks of treatment

After dose increases

As the body adapts, symptoms usually become milder or disappear completely. Many patients find that once they reach a stable maintenance dose, gastrointestinal side effects settle significantly.

Should you stop Mounjaro if you get sulphur burps?

Not necessarily.

Sulphur burps alone are not a reason to stop treatment. They are uncomfortable but usually manageable with dietary and behavioural changes.

However, if side effects are severe, persistent or affecting your quality of life, you should speak to your prescribing clinician. Dose adjustment or a slower titration schedule can often resolve the issue.

Final thoughts

Sulphur burps, nausea and occasional vomiting can occur on Mounjaro, particularly early in treatment. These symptoms are linked to slower digestion and changes in gut function and are usually temporary.

Understanding why they happen and making small adjustments to diet, portion size and eating habits can make a significant difference. Most people find that symptoms improve as their body adapts to the medication.

If you are experiencing ongoing or severe side effects, support is available. A personalised approach to dosing and lifestyle adjustments can help you stay on treatment safely and comfortably.

Reviewed by Irfan Mahmud, Pharmacist and Independent Prescriber (GPhC Reg. No: 2080386)

Irfan is a UK registered pharmacist and independent prescriber with expertise in weight management, metabolic health and lifestyle medicine. As the founder of Cuva Health, he is committed to providing safe, evidence based treatments and clear, trustworthy medical guidance.