Sulfur burps, those belches that taste like rotten eggs, are a common and usually harmless part of starting a GLP-1 medication, and they are not your fault. Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) slow down how fast your stomach empties. Food sits longer, and the natural bacteria in your gut have more time to break down its sulfur-rich parts into hydrogen sulfide, the gas behind that rotten-egg smell. They show up most when you first start or move up a dose, and for most people they settle within a few days to a few weeks. Smaller meals, easing off high-sulfur foods, staying hydrated, and a pharmacist-suggested over-the-counter remedy usually help. This is general information, not medical advice.
Why this is happening
First, the reassuring part: sulfur burps are one of the most common things people quietly look up after starting the shot, and on their own they are far more embarrassing than dangerous.
Here is what is actually going on. GLP-1 medications work partly by slowing gastric emptying, which is just the medical way of saying they slow how quickly food leaves your stomach. Cleveland Clinic explains this is part of how these medicines lower blood sugar and curb appetite. It is also why a meal can suddenly feel like it is just sitting there.
When food lingers, the sulfur-containing parts of it (found in eggs, meat, dairy, garlic, and vegetables like broccoli and cauliflower) spend more time with the bacteria in your gut. Those bacteria ferment it and release hydrogen sulfide, the exact same compound that gives rotten eggs their smell. The burp is simply that gas finding its way back up. It feels alarming and tastes worse, but it is a plumbing slowdown, not a sign that something is broken.
How long do sulfur burps last?
If you are hoping for a date on the calendar, here is the honest answer: sulfur burps are common enough that people compare notes about them constantly, but they have not been carefully counted in clinical trials, so no one can give you an exact percentage or a guaranteed end date without guessing. We would rather tell you that than make a number up.
What we do know is the pattern, and it is encouraging. Like the other digestive side effects of the shot, sulfur burps are most likely when you first start the medication or right after a dose increase, and they tend to ease as your body settles in. Cleveland Clinic notes the common stomach-related effects are more likely when you start the medication or take an increased dose. For most people that means a rough patch of a few days to a few weeks, especially when the dose is raised slowly.
If yours are dragging on, getting worse instead of better, or making it hard to eat, that is worth a message to your prescriber. For the bigger picture on what eases and when, see how long GLP-1 side effects last.
What you can do tonight
None of these will change your medication, and none of them are a reason to skip or alter a dose on your own. They are the gentle, prescriber- and pharmacist-approved things most people try first.
- Eat smaller, slower meals. A big or rushed meal sits and ferments. Smaller portions, chewed well, move through more comfortably. This is the single most helpful habit for most people.
- Ease up on high-sulfur foods for a little while, especially around a dose increase. The usual suspects are eggs, red meat, dairy, garlic, onions, and cruciferous vegetables like broccoli, cauliflower, cabbage, and Brussels sprouts. Sugar-free products with sorbitol, mannitol, or xylitol can ferment too. Our foods to eat and avoid guide has the full picture.
- Drink water and take a short walk after eating. Both gently help things keep moving instead of stalling.
- Ask your pharmacist about an over-the-counter option. Simethicone for gas and bismuth subsalicylate are the ones people ask about most. Your pharmacist can tell you in two minutes whether one fits with your other medicines.
- Talk to your prescriber about your titration. Moving up to the next dose more slowly is the most powerful lever there is, and it belongs to them, not to a forum. If side effects are rough, they may keep you at your current dose a little longer rather than push ahead.
When to call someone
Sulfur burps by themselves are almost never an emergency. The reason to know the warning signs is simply so you can tell the difference quickly and stop worrying about the ordinary ones.
Most of the time, though, a sulfur burp is just your digestion running in slow motion. Unpleasant, yes. Dangerous, almost never.
Questions people ask at 11pm
Why do my burps smell like rotten eggs on Ozempic? Because semaglutide slows your stomach down, food lingers, and gut bacteria turn its sulfur-rich parts into hydrogen sulfide gas, which smells like rotten eggs. It works the same way on tirzepatide (Mounjaro, Zepbound). It is a normal quirk of slowed digestion, not a sign the medicine is harming you.
How long do sulfur burps last on the shot? Usually a few days to a few weeks. They flare most when you start or increase your dose and calm down as your body adjusts, which a slow, prescriber-guided titration helps with. Burps that keep going or get worse are worth a call to your prescriber.
What stops sulfur burps fast? There is no guaranteed instant fix, but the things that help most people are smaller meals, cutting back on high-sulfur foods for a bit, drinking water, and a pharmacist-recommended over-the-counter remedy like simethicone. Please do not skip or change your dose to chase relief. Talk to your prescriber first.
How we reviewed this: this page was written from authoritative medical sources, including Cleveland Clinic's overview of GLP-1 agonists and a medically reviewed explainer on GLP-1 sulfur burps. See our editorial and review policy and sourcing standards. Where the evidence is thin, like the exact frequency of sulfur burps, we tell you that instead of inventing a number.
Every medical claim above is cited to a primary source such as an FDA label, the NIH, or a named clinical trial. See how we review and our sourcing & fact-check standards.