Sulfur burps — belches that smell like rotten eggs — are a common and usually harmless side effect of GLP-1 medications (semaglutide, sold as Ozempic and Wegovy; tirzepatide, sold as Mounjaro and Zepbound). They happen because these medicines slow how fast your stomach empties: food lingers, and gut bacteria ferment the sulfur-rich parts of it into hydrogen sulfide — the gas behind that rotten-egg smell. They are most likely when you start the medication or move up a dose, and they usually settle within days to a few weeks as your body adjusts. Smaller meals, easing off high-sulfur foods, and a pharmacist-suggested over-the-counter remedy often help. This is general information, not medical advice — talk to your prescriber about your own situation.
Why a GLP-1 makes your burps smell like sulfur
GLP-1 receptor agonists work partly by slowing gastric emptying — the rate at which food leaves your stomach. Cleveland Clinic notes this is part of how the medicines lower blood sugar and curb appetite, and it is also why meals can feel heavier than they used to.
When food sits longer, the sulfur-containing amino acids in it — cysteine and methionine, found in eggs, meat, dairy, and cruciferous vegetables — give gut bacteria more time to break them down. That fermentation produces hydrogen sulfide, the same compound responsible for the rotten-egg odor, and the burp is simply that gas coming back up. Sulfur burps specifically have not been well quantified in clinical trials, but the slowed-digestion mechanism is the widely accepted explanation, and belching and indigestion sit alongside the nausea and other GI effects that are the most commonly reported with this class.
How common are they, and how long do they last?
Sulfur burps are a recognized but under-studied GLP-1 side effect, so there is no precise prevalence figure to quote honestly. What is well established is the pattern: gastrointestinal effects are most likely when you start the medication or increase your dose, and they ease as your body adapts — Cleveland Clinic notes the common GI side effects are "more likely to happen when you start the medication or if you're taking an increased dose."
For most people, sulfur burps are a passing nuisance that improves within days to a few weeks. Like the broader GI side effects, they usually settle over the first weeks to couple of months of treatment, especially when the dose is stepped up gradually. If yours are not improving, are getting worse, or are interfering with eating, that is worth raising with your prescriber. For the bigger picture, see how long GLP-1 side effects last.
What actually helps
These are typical, prescriber- and pharmacist-directed steps — not a prescription, and never a reason to change your dose on your own:
- Eat smaller, slower meals. Large or rushed meals sit and ferment; smaller portions, chewed well, move through more comfortably.
- Ease off high-sulfur foods for a while, especially around a dose increase: eggs, red meat, dairy, and cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, cabbage). Sugar alcohols (sorbitol, mannitol, xylitol) in "sugar-free" products can ferment too. See foods to eat and avoid.
- Stay hydrated and take a gentle walk after eating to help things move along.
- Ask your pharmacist about an over-the-counter option — products such as simethicone or bismuth subsalicylate are commonly suggested, but check that one is right for you and your other medicines.
- Gradual dose titration is the single biggest lever, and it belongs to your prescriber. If side effects are rough, they may slow your step-up rather than push through it.
When to seek care
Most of the time, sulfur burps are just an unpleasant sign that digestion has slowed down — annoying, not dangerous. The point of knowing the red flags is so you can tell the difference quickly.
Frequently asked questions
Why do my burps smell like rotten eggs on Ozempic? Because semaglutide slows stomach emptying, food lingers and gut bacteria ferment its sulfur-containing parts into hydrogen sulfide gas, which smells like rotten eggs. It is the same mechanism on tirzepatide.
How long do sulfur burps last on a GLP-1? Usually days to a few weeks. They flare most when you start or increase the dose and ease as your body adjusts; gradual titration helps. Persistent or worsening burps are worth a call to your prescriber.
What stops sulfur burps fast? There is no guaranteed instant fix, but smaller meals, cutting back on high-sulfur foods, hydration, and a pharmacist-recommended over-the-counter remedy are the usual first steps. Do not change your dose to chase relief — talk to your prescriber.
How we reviewed this: written from authoritative sources, including Cleveland Clinic's overview of GLP-1 agonists and a medically reviewed answer on GLP-1 sulfur burps. See our editorial and review policy and sourcing standards. Where evidence is limited — as with the exact frequency of sulfur burps — we say so rather than overstating it.
Every clinical claim above is cited inline to a primary source. See how we review and our sourcing & fact-check standards.