# Sulfur burps, heartburn and reflux on GLP-1s

> Burping hit 7% on Wegovy and 4% to 5% on Zepbound, reflux 4% to 5%. Slower stomach emptying is why. What helps, and when to get care.

Source: https://morninghealth.app/guides/glp1-sulfur-burps-reflux · Updated 2026-10-13 · Morning (morninghealth.app)

Burping, indigestion and reflux are common, usually mild side effects of GLP-1 medicines. In the trials behind the US labels, burping was reported by 7% of adults on Wegovy 2.4 mg (vs under 1% on placebo) and 4% to 5% on Zepbound (vs 1%), and reflux by 5% on Wegovy (vs 3%) and 4% to 5% on Zepbound (vs 2%). Both medicines slow how fast your stomach empties, so food sits there longer, which helps explain the burps and heartburn. Smaller meals, eating slowly and staying upright after you eat help most people, and these symptoms tend to be strongest during dose increases.

## Key takeaways

- Indigestion (dyspepsia) was the most common of these: 9% on Wegovy 2.4 mg vs 3% on placebo, and 9% to 10% on Zepbound vs 4%.
- Burping (eructation) was reported in 7% on Wegovy vs under 1% on placebo, and 4% to 5% on Zepbound vs 1%. The labels do not track "sulfur burps" separately.
- Reflux (GERD) was reported in 5% on Wegovy vs 3%, and 4% to 5% on Zepbound vs 2%. Rates were lower in the Ozempic and Mounjaro diabetes trials, at 2.5% or less.
- Both labels say Wegovy and Zepbound delay gastric emptying. The Zepbound label adds that the delay is largest after the first dose and lessens over time.
- Chest pain, trouble swallowing, vomiting blood or black stool need urgent care. Chest pain is an emergency until proven otherwise.
- Before any surgery or procedure with anesthesia or deep sedation, tell your care team you take a GLP-1. The labels describe rare reports of food being inhaled into the lungs (pulmonary aspiration).

## How common are burping and reflux on Wegovy, Zepbound, Ozempic and Mounjaro?

Indigestion, burping and reflux each affected roughly 4% to 10% of people in the weight-loss trials, a few points above placebo. The table shows the rates from the placebo-controlled trials listed in each US label. Wegovy and Zepbound were studied for weight loss; Ozempic and Mounjaro, at lower doses, in type 2 diabetes.

| Symptom | Wegovy 2.4 mg | Placebo | Zepbound 5 to 15 mg | Placebo | Ozempic 0.5 and 1 mg | Placebo | Mounjaro 5 to 15 mg | Placebo |
|---|---|---|---|---|---|---|---|---|
| Indigestion (dyspepsia) | 9% | 3% | 9% to 10% | 4% | 2.7% to 3.5% | 1.9% | 5% to 8% | 3% |
| Burping (eructation) | 7% | under 1% | 4% to 5% | 1% | 1.1% to 2.7% | 0% | 2.5% to 3.3% | 0.4% |
| Reflux (GERD) | 5% | 3% | 4% to 5% | 2% | 1.5% to 1.9% | 0% | 1.7% to 2.5% | 0.4% |
| Bloating (abdominal distension) | 7% | 5% | 3% to 4% | 2% | not listed | not listed | 0.4% to 2.9% | 0.4% |
| Gas (flatulence) | 6% | 4% | 3% to 4% | 2% | 0.4% to 1.5% | 0.8% | 1.3% to 2.9% | 0% |

The Wegovy label also lists gastritis, which includes reflux gastritis, in 4% vs 1% on placebo, and names hiccups among gut reactions that were more common than on placebo. The labels warn that rates from different trials cannot be compared directly, so read this as "common and usually mild," not as a ranking of which medicine is gentler.

The daily Wegovy pill (25 mg) had side effects similar in type and frequency to the 2.4 mg injection, according to its label.

## Why do GLP-1s cause sulfur burps and heartburn?

The main reason is that these medicines slow how fast your stomach empties. Both the Wegovy and Zepbound labels state that the medicine delays gastric emptying. When a meal sits in the stomach longer, there is more time for gas to build and for stomach contents to push up into the food pipe, which you feel as burping, fullness or heartburn.

Sulfur burps are burps that smell like rotten eggs. They are not listed as their own side effect in any label; the trials counted all burping as eructation. The smell comes from sulfur gases. A common explanation is that food, especially protein-rich and sulfur-rich foods such as eggs, red meat and cabbage-family vegetables, sits longer in a slower stomach. This has not been measured in the trials, so treat it as a likely reason, not a proven one.

The Zepbound label notes that the slowing of gastric emptying is largest after the first dose and lessens over time. That matches what many people feel: the first weeks and the days after a dose increase are the burpiest, then things calm down.

## When do burping and reflux happen, and do they go away?

They tend to show up early and after each dose increase, then ease for most people. The Wegovy label says its gut reactions, including burping, indigestion and reflux, were reported most often during dose escalation. Wegovy starts at 0.25 mg and steps up every 4 weeks; Zepbound and Mounjaro start at 2.5 mg for 4 weeks and rise in 2.5 mg steps. The [titration schedules tool](/tools/titration-schedules) lays out each label schedule.

Many people notice that a big or late meal in the first few days after a shot is the trigger. If heartburn keeps you up at night or does not settle after a few weeks on the same dose, that is worth raising with your prescriber. Decisions about holding or changing a dose belong to your prescriber; follow your prescriber and the label.

## What helps with sulfur burps and reflux on a GLP-1?

Giving your slower stomach less to handle at once helps most. Simple habits that many people find useful:

- **Eat smaller meals, and stop at the first sign of fullness.** A plate that felt normal before the medicine can now overfill your stomach.
- **Eat slowly and chew well.** Putting your fork down between bites gives fullness signals time to arrive and means you swallow less air.
- **Stay upright after eating.** Avoid lying down for a few hours after a meal, and try to finish dinner well before bed. Raising the head of your bed can help with night-time reflux.
- **Go easy on fatty, fried and very rich food.** Fat stays in the stomach longest. Common reflux triggers also include large amounts of coffee, alcohol, chocolate, mint, spicy food and citrus or tomato sauces.
- **Cut back on fizzy drinks.** Carbonated water, soda and beer add gas to a stomach that is already slow to empty. Drinking through a straw or gulping can add air too.
- **Spread protein through the day.** If eggs or red meat seem to bring on rotten-egg burps, try smaller portions or other proteins such as yogurt, fish, chicken or tofu, and notice what changes.
- **Sip fluids between meals.** Large drinks with meals can make you feel fuller and push contents upward.
- **Watch tight waistbands.** Pressure on your belly after a meal can push stomach contents up.

If you want to try an over-the-counter antacid or acid reducer, ask your pharmacist first. Some acid medicines interact with other drugs, and GLP-1s can change how fast oral medicines are absorbed. If you need one most days for more than a couple of weeks, talk to your clinician.

## When are burping or heartburn a reason to get care?

Most GLP-1 burping and heartburn is a nuisance, not a danger. Some symptoms can point to something else and need prompt attention:

> Call emergency services for chest pain or pressure, especially if it spreads to your arm, jaw or back, or comes with shortness of breath, sweating or lightheadedness. Heartburn and a heart attack can feel alike, so do not wait to find out which it is.

Contact your clinician promptly, or seek care, if you have:

- trouble swallowing, pain when swallowing, or a feeling that food gets stuck
- vomiting blood or something that looks like coffee grounds, or black, tarry stool
- severe belly pain that will not go away, with or without vomiting, especially if it spreads to your back; this can be a sign of pancreatitis
- vomiting that will not stop, or you cannot keep fluids down; the labels warn that dehydration from vomiting or diarrhea can lead to kidney injury
- weight loss you cannot explain, or heartburn that keeps getting worse

A lump in your neck, trouble swallowing or ongoing hoarseness should also be checked, because both medicines carry a boxed warning about thyroid C-cell tumors seen in rats. It is not known whether this happens in people.

Both labels say severe gut reactions were more common on the medicine than on placebo: 4.1% on Wegovy vs 0.9%, and 1.7% to 3.1% on Zepbound vs 1%. They also say the medicines are not recommended for people with severe gastroparesis, a condition where the stomach empties very slowly.

## Why do I need to tell my care team before surgery or sedation?

Because a slower stomach can still hold food when you are put to sleep. Every one of these labels has a warning about pulmonary aspiration during general anesthesia or deep sedation. It says there have been rare reports of people on GLP-1 medicines inhaling stomach contents into their lungs during elective surgeries or procedures, even though they followed the usual fasting rules before.

The labels say there is not enough data yet to know whether changing the fasting rules or pausing the medicine lowers this risk. What they ask is simple: tell your healthcare providers, before any planned surgery or procedure, that you take a GLP-1. That includes procedures such as an endoscopy or colonoscopy with sedation and dental work under deep sedation. Your care team will decide what to do with your doses and your fasting plan; follow their instructions and the label.

## How Morning helps

Morning's side-effect check-ins show whether burping or heartburn cluster around shot day, and the shot log keeps the dose plan you and your clinician set, so you can see whether symptoms line up with a step-up. Ask Sunny, your chat coach, can suggest lighter meal ideas and talk through side effects any time, never dose advice. The doctor report gathers your symptom pattern and medicines, which is handy to bring to an appointment or a pre-procedure visit.

## Questions

### What causes sulfur burps on Ozempic or Mounjaro?

The labels do not list sulfur burps separately; they count all burping as eructation, reported in 1.1% to 2.7% on Ozempic and 2.5% to 3.3% on Mounjaro. These medicines slow stomach emptying, and a common explanation is that food, especially sulfur-rich foods, sits longer and produces sulfur gases.

### How long do sulfur burps last on a GLP-1?

For most people they are worst in the first weeks and after a dose increase, then ease. The Wegovy label says gut reactions were most frequent during dose escalation, and the Zepbound label says the slowing of stomach emptying is largest after the first dose and lessens over time.

### Can GLP-1s cause GERD?

Reflux was reported more often on these medicines than on placebo: 5% on Wegovy vs 3%, and 4% to 5% on Zepbound vs 2%. If you already have reflux, tell your prescriber before starting, and mention it if it gets worse.

### Is chest pain on a GLP-1 just heartburn?

Do not assume it is. Chest pain or pressure, especially with shortness of breath, sweating or pain spreading to the arm or jaw, needs emergency care right away.

### Should I stop my GLP-1 before a colonoscopy or surgery?

Tell the team doing the procedure that you take a GLP-1, well ahead of time. The labels say there is not enough data to set a rule, so follow your care team's instructions and the label rather than deciding on your own.

### Can I take an antacid with a GLP-1?

Many people do, but ask your pharmacist first. GLP-1s slow stomach emptying, which can change how other oral medicines are absorbed, and some acid reducers interact with other drugs.

## Sources

- [Wegovy (semaglutide) US prescribing information, Novo Nordisk](https://www.novo-pi.com/wegovy.pdf)
- [Zepbound (tirzepatide) US prescribing information, Eli Lilly](https://pi.lilly.com/us/zepbound-uspi.pdf)
- [Ozempic (semaglutide) US prescribing information, Novo Nordisk](https://www.novo-pi.com/ozempic.pdf)
- [Mounjaro (tirzepatide) US prescribing information, Eli Lilly](https://pi.lilly.com/us/mounjaro-uspi.pdf)
- [DailyMed: Wegovy label](https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=wegovy)
- [DailyMed: Zepbound label](https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=zepbound)
- [DailyMed: Ozempic label](https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=ozempic)
- [DailyMed: Mounjaro label](https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=mounjaro)