Sulphur burps on Mounjaro: causes, how long they last and how to stop them

Mounjaro can come with side effects like nausea and constipation, but sulphur burps are the one that catches most people off guard. If yours smells like rotten eggs, you're not imagining it and you're definitely not alone.

Also called eggy burps, they're caused by hydrogen sulphide gas building up in your digestive system as Mounjaro slows your digestion. They're not dangerous, but they are hard to ignore. (Taking Wegovy instead? See our guide to sulphur burps on Wegovy.)

A number of factors can increase the likelihood of getting them, from what you eat to the makeup of your gut bacteria. But there are also plenty of simple lifestyle adjustments and over-the-counter remedies that can make a real difference. Here's what you need to know.

Key takeaways

• Sulphur burps are caused by hydrogen sulphide gas building up as Mounjaro slows your digestion
• They are harmless and usually at their worst around weeks 2 to 3, easing significantly by weeks 6 to 8
• Reducing high-sulphur foods like eggs, red meat, and cruciferous vegetables can make a noticeable difference
• Over-the-counter remedies like simethicone (Wind-Eze) and peppermint can provide quick relief
• If symptoms are persistent, affecting your daily life, or not improving after dietary changes, speak to your clinician

What are sulphur burps (eggy burps)?

Sulphur burps are burps that smell or taste like rotten eggs. The smell comes from hydrogen sulphide (H2S) gas, which is produced in the digestive system when sulphur-containing compounds are broken down by gut bacteria. Foods particularly high in sulphur include eggs, dairy, red meat, onions, garlic, cruciferous vegetables like broccoli and cabbage, beans, and alcohol like beer and wine.

Sulphur burps can occur outside of weight loss medication, usually linked to eating high-sulphur foods, gut infections like H. pylori, or digestive conditions like IBS. But people taking Mounjaro (tirzepatide) tend to experience them more frequently, and that's directly related to how it works.

Why does Mounjaro cause sulphur burps?

Mounjaro works by slowing down gastric emptying, the rate at which food moves out of your stomach. It does this through two separate pathways, targeting both GLP-1 and GIP receptors, which is part of what makes it so effective. The downside is that food sits in your stomach for longer, giving gut bacteria more time to ferment sulphur-containing compounds and produce hydrogen sulphide gas, the source of that rotten egg smell.

There is also early evidence that Mounjaro may alter gut bacteria composition, contributing further to sulphur burps. Up to one in ten people experience burping as a side effect of Mounjaro.

Burps often start when you first begin Mounjaro or after a dose increase, then settle as your body adjusts or once you make a few lifestyle changes. If yours started before you began Mounjaro, or are getting worse rather than better over time, the cause may be something other than the medication, such as an H. pylori infection, which we cover below.

Here, Dr Earim Chaudry explains why some people experience sulphur burps on Mounjaro, when they're most likely to happen, and what you can do about them.

How long do sulphur burps last?

How long sulphur burps last depends on what's triggering them, how your body responds to the medication, and any lifestyle changes you make. That said, there are general patterns that can help set expectations. Here's a typical timeline:

If you've recently increased your dose, they may return briefly but usually settle faster than the first time, as your body has already been through the adjustment process once.

If your burps are particularly persistent and not improving, it may be worth reviewing your diet or speaking to your prescriber about whether your current dose is right for you. Reducing to a lower dose temporarily can sometimes make a noticeable difference within a week or two.

How to get rid of sulphur burps instantly

There's no single remedy that suits everyone, but a few options work quickly. If you need relief within 30 to 60 minutes, these can help:

OTC remedies for sulphur burps

Simethicone

Anti-gas tablets available over the counter (Wind-Eze, Infacol). They break up gas bubbles in the gut and work quickly. They are safe to take alongside Mounjaro.

Bismuth subsalicylate (Pepto-Bismol)

Helps neutralise the rotten egg smell rather than just masking it. Safe for occasional use but avoid long-term use without medical advice.

Peppermint

Peppermint relaxes smooth muscle in the digestive tract, easing gas and bloating. Try peppermint tea for gentle relief, or enteric-coated peppermint oil capsules such as Colpermin, which reach the small intestine intact and may offer more targeted relief.

Ginger tea

Well known for its anti-nausea properties, ginger can also help speed up digestion and reduce gas build-up. Safe to take with Mounjaro.

Activated charcoal capsules

Can absorb gas and reduce odour. Do not take them within two hours of Mounjaro, or any other medication as they can reduce absorption.

Water

Simple but effective. A large glass of water helps flush the system and dilute gas-producing compounds in the stomach.

Important safety note:

Over the counter (OTC) remedies are generally well tolerated but are not risk-free. Some may interact with Mounjaro and other medications. Always check with your clinician or pharmacist before starting any new supplement or OTC medication.

How to stop sulphur burps on Mounjaro

Adjust what you eat

Foods high in sulphur give gut bacteria more material to produce H2S gas. Temporarily reducing these can make a noticeable difference:

• Eggs and dairy products
• Red meat and poultry
• Cruciferous vegetables: broccoli, cauliflower, cabbage, brussels sprouts, kale
• Onions and garlic
• Beans and lentils
• Alcohol and carbonated drinks

You don't need to cut these out forever, just reduce them while your body is adjusting, then reintroduce gradually. Increasing your fibre intake at the same time may help, as some research suggests fibre can lower H2S levels. If you want to get the most out of your medication, your wider Mounjaro diet is worth thinking about too.

Eat smaller, more frequent meals

Less food in your stomach at any one time means less fermentation and less gas. Shifting from three large meals to five or six smaller ones throughout the day can make a noticeable difference for some people.

Don't eat late at night

Food sitting in a slowed stomach overnight is a recipe for morning eggy burps. Try to finish eating at least two to three hours before bed.

Move after meals

Even a 10 to 15 minute walk after eating can help food move through your digestive system more efficiently, reducing gas build-up. Aim for around 150 minutes of moderate movement per week alongside two strength sessions, which supports your weight loss progress on Mounjaro.

Think about injection timing

Some people find that taking their injection in the evening helps reduce the intensity of side effects during the day. There is no clinical trial data to confirm this definitively, but it is a practical adjustment worth trying if daytime burps are affecting your work or social life.

Try probiotics

Probiotics are live bacteria that can help rebalance the gut microbiome and may help regulate H2S production over time. They are not a quick fix but can complement dietary changes well. Check with your clinician first as probiotics are not recommended for everyone.

Digestive enzyme supplements

Products containing amylase, lipase, and protease can help break down food more efficiently and reduce gas production. These are particularly useful if certain foods consistently trigger your symptoms. Alpha-galactosidase is worth considering specifically if beans, lentils or cruciferous vegetables are your main triggers, as it helps digest the complex sugars in these foods before they reach your gut bacteria.

Treating sulphur burps on Mounjaro: at a glance

A combined approach often works best. A daily probiotic, simethicone after meals, and some simple dietary changes can make a real difference within a few weeks.

Sulphur burps and diarrhoea on Mounjaro

Some people experience sulphur burps and diarrhoea at the same time on Mounjaro. This isn't unusual. Both happen because Mounjaro slows down digestion, and both tend to be most common in the first few weeks of treatment or after a dose increase.

The good news is that the same adjustments help with both. Smaller meals, avoiding high-fat foods, staying hydrated, and not eating late at night can all help.

That said, diarrhoea is worth mentioning to your prescriber if it's severe, not improving after a few days, or comes with other symptoms like fever, stomach pain, or blood in your stool.

Could it be H. pylori rather than Mounjaro?

If your sulphur burps started before you began Mounjaro or are getting worse rather than better over time, or are accompanied by symptoms like persistent stomach pain, nausea, bloating, or vomiting, it is worth considering whether H. pylori might be a contributing factor.

H. pylori is a bacterial infection of the stomach lining that affects up to 2 in 5 people in the UK, often without causing obvious symptoms. Most people who carry it never develop any problems at all, with 8 to 9 in 10 experiencing no symptoms from the infection. Research has found that H. pylori infection is associated with elevated sulphur compound levels, the same gases that produce the rotten egg smell, particularly in people with erosive stomach damage.

This doesn't mean your burps aren't related to your medication. They may very well be. But if symptoms are unusually severe or don't improve as expected, it is worth mentioning to your clinician. H. pylori is straightforward to test for and treatable with a short course of antibiotics.

When should you speak to your clinician about sulphur burps?

Sulphur burps on Mounjaro are usually harmless and temporary, but there are situations where it's worth getting in touch with your clinician:

• Your burps are severe and not improving after several weeks despite dietary changes
• You have diarrhoea, vomiting, or stomach pain alongside your burps that isn't settling
• Your symptoms started or significantly worsened after a dose increase and aren't easing
• You are concerned your symptoms might be related to something other than your medication, such as H. pylori

If you are a Voy patient, you can message your clinician directly through the app at any time.

Side effects support at Voy

"If you're using Voy and you experience any side effects, rest assured that our expert clinicians are just a message or phone call away. They can adjust your dose, prescribe medication to ease your symptoms, or simply offer reassurance.

Everyone responds differently to weight loss treatment and we'll help you find what feels right for you."

Phoebe Fox - Weight Loss Specialist

Your weight loss journey

Weight loss medications can drive serious results, though they can also come with not-so-glamorous side effects. Most of the time these are mild and clear on their own. It's understandable to be concerned. Our research found that two in three people felt side-effect risks were a major barrier to starting weight loss medication. But for people who have tried to lose weight another way and didn't see the results they wanted, weight loss injections can be a game changer.

With weight loss medication and healthy lifestyle changes, you could lose up to 25% of your starting weight if you stick with your routine for over a year.