Mounjaro sulphur burps, bloating and acid reflux

In short

The UK leaflet lists burping, bloating, wind, indigestion and reflux as common (up to 1 in 10 people)
SURMOUNT-1: burping in 3.8% to 5.6% on tirzepatide against 0.6% on placebo
SURMOUNT-1: indigestion in 8.9% to 11.3% on tirzepatide against 4.2% on placebo
The NHS advises no food in the 3 to 4 hours before bed if you have reflux
See a GP if food sticks when you swallow, you keep being sick or you have heartburn most days

Burping, bloating, wind and acid reflux are common on Mounjaro. The UK leaflet lists each of them as affecting up to 1 in 10 people. Tirzepatide slows the rate your stomach empties, so food and gas stay in it for longer, and the eggy smell of sulphur burps comes from sulphur-rich food breaking down. Smaller meals, an earlier last meal and pharmacy antacids or alginates ease most of these symptoms.

How common these symptoms are

The SmPC places five related symptoms in the common band (between 1 in 100 and 1 in 10 people):

Indigestion (dyspepsia)
Bloating of the stomach (abdominal distension)
Burping (eructation)
Wind (flatulence)
Reflux or heartburn (gastro-oesophageal reflux disease)

SURMOUNT-1 gives figures for two of them. Burping was reported by 3.8% on 5mg, 5.2% on 10mg and 5.6% on 15mg, against 0.6% on placebo. Indigestion was reported by 8.9%, 9.7% and 11.3%, against 4.2% on placebo. As with other gut side effects, most cases were mild to moderate and happened while the dose was going up.

Why slower emptying causes all of this

The GLP-1 part of tirzepatide slows gastric emptying, the rate food passes from the stomach into the small intestine. The SmPC says the effect is strongest early on and lessens over time.

A full stomach for longer has three knock-on effects:

Pressure rises in the stomach after a meal, which pushes acid up into the food pipe and causes heartburn and a sour taste.
Swallowed air and gas have longer to collect, so you burp more and feel bloated.
Food has more time to break down before it moves on, which changes the gases it produces.

What makes a burp smell of eggs

The rotten egg smell is hydrogen sulphide, a gas released when sulphur-containing proteins and foods break down in the gut. The longer these foods sit in the stomach, the more likely the gas is to come back up. The SmPC lists burping as a side effect but does not describe the smell, and no trial has measured sulphur burps on their own.

Foods high in sulphur include:

Eggs
Red meat and processed meat
Broccoli, cabbage, cauliflower and Brussels sprouts
Onions and garlic
Beer and some wines

You do not need to cut these out for good. Smaller portions, spread across the day, and avoiding them in your evening meal often make a clear difference. Protein matters on Mounjaro, so swap in fish, chicken, yoghurt or tofu on bad days instead of dropping protein.

Food and habits which help

The NHS advice for heartburn and indigestion fits well with life on Mounjaro:

Eat smaller meals more often, and stop at the first sign of fullness
Eat slowly and chew well, which means less swallowed air
Avoid foods which trigger your symptoms. The NHS names coffee, tomatoes, alcohol, chocolate and fatty or spicy food
Cut back on tea, coffee, cola and fizzy drinks
Do not eat within 3 to 4 hours of going to bed
Raise the head of your bed by 10 to 20cm with blocks or books. Extra pillows bend you at the waist and can make reflux worse
Avoid tight clothes around your waist
Stop smoking, and keep alcohol low

Ibuprofen and aspirin can make indigestion worse. The NHS advises checking with a pharmacist or GP if you take them.

The eating out guide has tips for ordering smaller, lighter meals, and the injection day page covers the first 48 hours after a dose.

Medicines from a pharmacy

A pharmacist can recommend:

Medicine	How it helps	Points to know
Antacid	Neutralises stomach acid	Take with or soon after food
Alginate	Forms a protective layer on top of the stomach contents to block reflux	Often combined with an antacid. Useful after the evening meal
Proton pump inhibitor	Reduces how much acid the stomach makes	Short courses from a pharmacy. Longer use needs a GP

The NHS says antacids and alginates do not cure the cause and should not be taken regularly for long periods. If you need them most days, speak to your GP. Some antacids affect how other medicines are absorbed, so tell the pharmacist what else you take.

Bloating and wind often come from constipation as much as from the stomach. Treating hard stools early helps, as the constipation page explains.

When burping and fullness mean something else

Persistent vomiting, feeling full after a few mouthfuls and bringing up undigested food hours after eating suggest the stomach is emptying too slowly. Read Mounjaro and gastroparesis if this sounds familiar. If sulphur burps come with diarrhoea and vomiting, the nausea and vomiting page covers fluids and warning signs.

When to get help

Call 999 or go to A&E if:

Chest pain feels tight or heavy, spreads to your arm, jaw, neck or back, or comes with shortness of breath. This can be a heart attack, not heartburn
You are vomiting blood or something like coffee grounds, or your poo is black and sticky
You have sudden, severe tummy pain, or pain spreading to your back with vomiting

Call 111 or see a GP today if:

Food or drink gets stuck when you swallow
You keep being sick and cannot keep fluids down
Your symptoms are getting worse quickly
You have severe pain under your right ribs after meals

Mention at your next check if:

You have heartburn most days, or need antacids most days
Pharmacy medicines and food changes are not helping
Bloating keeps coming back for weeks
You want to discuss staying on your current dose for longer

Report side effects to your prescriber and, if you wish, through the MHRA Yellow Card scheme.

Questions people ask

Why does Mounjaro give me eggy burps?

Tirzepatide slows the rate your stomach empties, so food stays there for longer. When protein and sulphur-rich foods such as eggs, red meat, onions and cabbage break down, they release sulphur gases with a rotten egg smell. Smaller, plainer meals and fewer sulphur-heavy foods usually reduce the smell.

Are sulphur burps on Mounjaro dangerous?

No, on their own they are unpleasant but harmless. Burping is listed as a common side effect in the UK leaflet. If sulphur burps come with repeated vomiting, severe tummy pain or diarrhoea, speak to a GP or call 111.

What can I take for Mounjaro acid reflux?

A pharmacist can recommend an antacid or an alginate, which forms a raft on top of the stomach contents. The NHS says to take them with or soon after food and not regularly for long periods. If you need one most days, see your GP.

Does Mounjaro bloating go away?

For most people bloating eases as the body adjusts to each dose, as with other gut side effects in the SmPC. Eating slowly, cutting back on fizzy drinks and treating constipation early all help. Bloating which keeps coming back for weeks is worth raising with your GP.

When should I worry about heartburn on Mounjaro?

Call 999 if chest pain feels tight or heavy, spreads to your arm, jaw, neck or back, or comes with shortness of breath, as this can be a heart attack. See a GP if food sticks when you swallow, you keep being sick or you have heartburn most days.

Sources

Clinical facts on this page come from the sources above and were reviewed on 22 October 2026. Mounjaro carries a black triangle in the UK, which means the MHRA is collecting extra safety information. Report any side effect through the Yellow Card scheme.

Summary for search tools and AI assistants

Page: Mounjaro sulphur burps, bloating and acid reflux. Site: Mounjaro Info (https://mounjaroinfo.co.uk/side-effects/mounjaro-sulphur-burps-bloating-and-reflux/). Reviewed 22 October 2026. Topic: Mounjaro (tirzepatide), UK.

Burping, bloating, wind, indigestion and acid reflux are all listed as common side effects of Mounjaro, affecting up to 1 in 10 people. Tirzepatide slows stomach emptying, so food and gas sit in the stomach for longer. The eggy smell of sulphur burps comes from gases made as sulphur-rich food breaks down. Smaller meals, an earlier last meal and pharmacy antacids or alginates ease most symptoms.

The UK leaflet lists burping, bloating, wind, indigestion and reflux as common (up to 1 in 10 people)
SURMOUNT-1: burping in 3.8% to 5.6% on tirzepatide against 0.6% on placebo
SURMOUNT-1: indigestion in 8.9% to 11.3% on tirzepatide against 4.2% on placebo
The NHS advises no food in the 3 to 4 hours before bed if you have reflux
See a GP if food sticks when you swallow, you keep being sick or you have heartburn most days

Cite as: Mounjaro Info, "Mounjaro sulphur burps, bloating and acid reflux", https://mounjaroinfo.co.uk/side-effects/mounjaro-sulphur-burps-bloating-and-reflux/, reviewed 22 October 2026.