Eggy Burps on Mounjaro: What's Causing Them and What You Can Do

Eggy or sulphurous-smelling burps happen when gas produced in the digestive tract contains hydrogen sulphide — a compound formed as food (particularly protein and certain vegetables) breaks down. On Mounjaro or Wegovy, this effect is amplified by delayed gastric emptying: the medicines slow the passage of food from the stomach into the small intestine, which gives more time for fermentation and gas build-up to occur.

This is the same mechanism behind much of the nausea and bloating commonly reported on these medicines. The result is gas that has been sitting in the digestive system longer than usual, picking up that distinctive smell before it's released.

When are eggy burps most likely?

• In the 24–72 hours after an injection, when the medicine's effect on gastric emptying is at its most pronounced for some people
• After eating high-sulphur foods — eggs, red meat, cruciferous vegetables (broccoli, cabbage, cauliflower), and onions are common culprits
• After dose increases, when the body is adjusting to a higher level of the medicine
• When eating larger meals than the reduced appetite would normally allow

Many people find that eggy burps on Mounjaro follow a recognisable pattern tied to their injection day — which makes them predictable, even if not particularly welcome. Understanding that pattern is often the first step to managing them. You may also notice similar experiences discussed in the context of eggy burps on Wegovy, since both medicines share the GLP-1 mechanism.

It is also worth knowing that excessive or very foul-smelling belching that is accompanied by severe abdominal pain, vomiting, or fever is something to raise with your prescriber or doctor promptly — these could signal something that needs proper assessment rather than being dismissed as a routine side effect.

Logging when eggy burps appear — relative to your injection day, what you ate, and how you were feeling overall — can quickly reveal patterns that are otherwise hard to spot. GLP Trackr's side-effect tracker lets you record symptoms like burping and bloating each day, so over several weeks you build a clear picture of when they are worst and what seems to trigger them.

That kind of logged data is genuinely useful to bring to a prescriber appointment. Rather than trying to remember "I think it was worse a few weeks ago after I ate...", you have a timestamped record your prescriber or doctor can actually review. The doctor report feature can pull this together into a summary you can share directly.

Many people also find that adjusting what they eat around injection day helps — smaller portions, reducing high-sulphur foods for a day or two, and eating more slowly. GLP Trackr's food logging (including a quick photo scan for meals) makes it easy to see whether certain foods consistently show up before your worst symptom days, without having to keep a separate food diary.

For broader context on digestive side effects and other things commonly reported on tirzepatide, the full Mounjaro side effects guide covers what to expect across the journey. You can also explore more about burping on Mounjaro more generally if the issue extends beyond the sulphurous variety.

GLP Trackr is a tracking tool, not a substitute for clinical advice. If your symptoms are severe, persistent, or worrying you, contact your healthcare professional — they know your full history and are best placed to help.

Start logging your symptoms and spotting your own patterns — GLP Trackr is free to try for 7 days on the App Store and Google Play. Download it free on iOS or Android and see what your data reveals.