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    Sulphur Burps on Mounjaro: Why They Happen and How to Stop Them

    Sulphur or "rotten egg" burps are a common Mounjaro side effect. A pharmacist explains the cause, which foods make it worse, and what genuinely helps.

    Jimah Alsaai MPharmJimah Alsaai MPharmSuperintendent Pharmacist
    GPhC 2232652     Reviewed September 2026
    Updated July 2026 · 5 min read

    If you've started Mounjaro and developed burps that taste or smell of rotten eggs, you're not imagining it and you're not alone. It's an unpleasant but generally harmless side effect with a clear mechanism, and it usually responds well to a few changes.

    What causes sulphur burps on GLP-1 treatment

    Tirzepatide slows gastric emptying, which is part of how it keeps you full. Food therefore sits in the stomach longer. Sulphur-containing proteins in that food are broken down by gut bacteria, producing hydrogen sulphide gas, which is what gives the rotten-egg smell. Slower transit means more time for that process. It's a predictable consequence of the mechanism, not a sign that something has gone wrong.

    Foods that commonly make it worse

    • High-sulphur foods: eggs, red meat, garlic, onions, broccoli, cauliflower, cabbage, Brussels sprouts.
    • Dairy, for some people.
    • Protein shakes containing whey.
    • Carbonated drinks, which add gas and encourage burping.
    • Very high-fat meals, which slow gastric emptying even further.

    What helps

    1. Smaller, more frequent meals rather than a couple of large ones.
    2. Temporarily reduce very high-sulphur foods, especially around dose increases.
    3. Lower the fat content of meals, since fat slows gastric emptying further.
    4. Avoid fizzy drinks.
    5. Stay upright for a while after eating.
    6. Stay hydrated.
    7. Eat slowly, swallowed air worsens belching.
    8. If it's severe, discuss slowing your titration with your prescriber.

    How long does it last?

    Usually worst in the days after a dose increase, and settling within one to two weeks as the gut adapts. Persisting or severe symptoms warrant review.

    See also Mounjaro side effects and what to eat on Mounjaro.

    When to see your pharmacist or doctor

    • Sulphur burps with severe abdominal pain, persistent vomiting, or inability to keep fluids down. This needs prompt medical assessment.
    • Severe upper abdominal pain radiating to the back, a possible sign of pancreatitis, so seek urgent care.
    • Symptoms that don't settle within a couple of weeks of a dose increase.
    Urgent help, genuine medicines and the official leaflets

    Frequently asked questions

    Usually not. They're a consequence of slowed digestion. But combined with severe pain or persistent vomiting they need assessment.

    Usually within one to two weeks of a dose increase as the gut adapts.

    Not necessarily, but if they're severe, a slower titration is a reasonable conversation to have with your prescriber.

    Yes, both slow gastric emptying.

    Speak to your pharmacist first, as some remedies interact or mask symptoms that are worth investigating.

    Keep reading

    Sources · 2Show
    1. Mounjaro Summary of Product Characteristics, electronic medicines compendium.
    2. Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med 2022.

    Reviewed by Jimah Alsaai MPharm, GPhC 2232652, Superintendent Pharmacist, QuickCare Pharmacy.

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