Sulfur Burps on GLP-1: Why They Happen and What to Eat

Burping is a recognised side effect of Mounjaro, Zepbound, Ozempic and Wegovy. When the burps smell of rotten eggs, people call them sulfur (or sulphur) burps, or eggy burps. They're unpleasant but rarely a sign of anything serious, and what helps most is simple: smaller meals, less fat, fewer fizzy drinks and eating more slowly. Like most stomach side effects, they're most common while your dose is going up and tend to settle once it's stable.

How common they are

In the trials behind the US labels, burping was reported by 7% of people on Wegovy, against fewer than 1% on placebo, and by 4 to 5% on Zepbound, against 1%. So it's a real effect of the medication, though most people never get it. Both labels list related stomach symptoms too: indigestion, bloating, wind and heartburn.

Some burping is normal for everyone. The NIH says people typically burp up to 30 times a day. It becomes a problem when it's frequent, uncomfortable or smelly.

Why GLP-1s cause sulfur burps

Semaglutide (in Ozempic and Wegovy) and tirzepatide (in Mounjaro and Zepbound) both slow down how quickly your stomach empties, which is part of how they keep you feeling full. The 2025 joint advisory from four US obesity and nutrition societies links that slower emptying to bloating, fullness and nausea, and lists burping among the less common side effects.

The smell is the part nobody has studied. The trials counted burps, not what they smelled like. The rotten-egg note comes from sulfur gases such as hydrogen sulfide, which gut bacteria make by breaking down the sulfur-containing building blocks of protein. In a controlled feeding study, the more meat people ate, the more sulfide their gut bacteria produced. That study measured the large intestine, not the stomach, so the link to burps is a likely explanation rather than a proven one: a big, protein-rich or fatty meal staying longer in a slower stomach.

Do they go away?

Usually, yes. The Wegovy label says its stomach side effects, burping among them, were reported most often while the dose was being increased. For tirzepatide, the Zepbound label says the slowing of the stomach is largest after the first dose and fades over time. So expect sulfur burps to flare after a dose increase and settle as your body adjusts.

What makes them worse

• Big meals. A slower stomach holds a large meal for longer. Both the advisory and the NIH suggest smaller, more frequent meals.
• Fatty and fried food. The advisory notes that fat slows the stomach further, and the NIH says high-fat foods can increase bloating.
• Swallowed air. Fizzy drinks, beer, chewing gum, hard sweets, straws, eating fast and talking while you eat all make you swallow more air, which comes back up. The NIH suggests cutting these first if you burp a lot.
• Alcohol. The advisory says alcohol may worsen nausea and reflux on a GLP-1. See alcohol on a GLP-1.
• A lot of protein in one go. If your burps follow a big plate of meat or a three-egg breakfast, try a smaller portion rather than cutting the food out, and make up the protein at other meals.

What to eat instead

You don't need a special diet. The aim is to give your stomach less to deal with at once while keeping your protein up, because protein protects your muscle while you lose weight.

• Eat smaller meals more often, and stop at the first sign of fullness.
• Spread your protein across the day instead of saving it for one big meal. The protein guide shows how much you need.
• Choose leaner protein and lighter cooking: chicken, fish, Greek yogurt, cottage cheese, tofu or beans, grilled, baked or poached rather than fried.
• Swap fizzy drinks for still ones: water, tea or coffee.
• Eat slowly, sitting down, as the NIH suggests.
• Keep a short diary. The NIH notes that a record of what you eat and drink, alongside your symptoms, helps a doctor or dietitian spot triggers. Note what you ate in the hours before a bad bout.

Lower-fat, protein-rich recipes from the site:

• Chicken and White Bean Soup: 30 g protein, 5 g fat
• Cottage Cheese Ice Cream: 32 g protein, 3 g fat
• High-Protein Greek Yogurt Bowl: 26 g protein, 9 g fat
• Berry Protein Smoothie: 26 g protein, 4 g fat; drink it from a glass rather than through a straw

Burps with nausea, diarrhea or heartburn

Sulfur burps often come with other stomach side effects, especially early on.

• Nausea. Managing nausea has foods that go down easily when you're queasy.
• Diarrhea. The advisory suggests avoiding large or high-fat meals. Keep drinking: both labels warn that losing fluid through diarrhea or vomiting can lead to dehydration and kidney problems. See diarrhea on a GLP-1 and electrolytes.
• Heartburn or a sour taste. That points more to reflux, which both labels list as a common side effect. The NIH advice for reflux is to finish eating at least 3 hours before you lie down. Heartburn and acid reflux on a GLP-1 covers what helps, and foods to limit on a GLP-1 the rest.

When to see a doctor

Sulfur burps on their own aren't dangerous. The NIH's general advice for gas is to see your doctor if symptoms bother you, change suddenly, or come with other symptoms such as stomach pain, constipation or diarrhea.

Call your healthcare provider straight away if you have:

• severe stomach pain that won't go away, with or without vomiting, sometimes felt through to your back, which can be a sign of pancreatitis
• pain in your upper stomach with fever, yellowing skin or eyes, or pale, clay-coloured stools, which can mean gallbladder problems
• vomiting or diarrhea that won't stop, or you can't keep fluids down

These warning signs come from the Wegovy and Zepbound labels. Don't change your dose yourself. If side effects are hard to live with, tell your prescriber: an expert consensus on GLP-1 side effects recommends flexibility while the dose is being increased. A pharmacist can advise on over-the-counter remedies that are safe with your other medicines.

General nutrition information, not medical advice. If side effects make it hard to eat well, your prescriber or a dietitian can help.