- Diarrhea is common: 30% on Wegovy 2.4 mg vs 16% on placebo, and up to 23% on Zepbound vs 8%. Burping affected 7% on Wegovy vs under 1% on placebo.1,2
- Episodes are usually short. In the STEP 1–3 trials the median diarrhea episode lasted 3 days, and most stomach symptoms came during dose increases.5
- "Sulfur burps" is an informal term. Labels record burping but not its smell. Diarrhea that does not stop, or severe belly pain, needs a call to your doctor.1,2
How common are diarrhea, burping and heartburn on a GLP-1?
The US prescribing information for each drug has a table of side effects from the placebo-controlled trials. For the weight-loss drugs, the trials were in adults with obesity or overweight followed for up to 68 weeks (Wegovy) or 72 weeks (Zepbound).1,2
| Side effect | Wegovy 2.4 mg | Placebo | Zepbound 5 / 10 / 15 mg | Placebo |
|---|---|---|---|---|
| Diarrhea | 30% | 16% | 19 / 21 / 23% | 8% |
| Indigestion (dyspepsia) | 9% | 3% | 9 / 9 / 10% | 4% |
| Bloating (abdominal distension) | 7% | 5% | 3 / 3 / 4% | 2% |
| Burping (eructation) | 7% | under 1% | 4 / 5 / 5% | 1% |
| Gas (flatulence) | 6% | 4% | 3 / 3 / 4% | 2% |
| Reflux (GERD) | 5% | 3% | 4 / 4 / 5% | 2% |
Rates were lower in the placebo-controlled diabetes trials. In people with type 2 diabetes, diarrhea was reported by 8.5% on Ozempic 0.5 mg and 8.8% on 1 mg vs 1.9% on placebo, and burping by 2.7% and 1.1% vs 0%.3 On Mounjaro, diarrhea ranged from 12% to 17% vs 9% on placebo, and burping from 2.5% to 3.3% vs 0.4%.4
The Wegovy label also lists gastritis, hemorrhoids and hiccups as stomach-related reactions that were more common than on placebo.1 For nausea and vomiting, see GLP-1 nausea. For the opposite problem, see GLP-1 constipation.
How long does GLP-1 diarrhea last?
A pooled analysis of the STEP 1, 2 and 3 trials looked at how long each stomach side effect lasted. Individual diarrhea episodes were short, with a median of 3 days, about the same as diarrhea on placebo. Diarrhea stayed more common on semaglutide than placebo throughout the trials, but became less common over time in people who kept taking it.5
Timing follows dose changes. The Wegovy label says stomach reactions were most often reported during dose escalation. The Zepbound label says most nausea, vomiting and diarrhea occurred during dose escalation and decreased over time.1,2 In the SURMOUNT-1 to -3 trials of tirzepatide, first use of an antidiarrheal medicine was most common in the first 24 weeks, which included the dose escalation period.6
Few people stopped because of diarrhea. In the Wegovy weight-loss trials, 0.7% stopped treatment for diarrhea vs 0.1% on placebo.1
What are sulfur burps, and why might GLP-1s cause them?
"Sulfur burps" is what people online call burps that smell or taste like rotten eggs. It is not a medical term. The trials recorded burping as "eructation" but did not record what it smelled like. We searched PubMed for studies of sulfur burps on semaglutide or tirzepatide and found none.
What is known: the labels state that both semaglutide and tirzepatide delay gastric emptying, meaning food leaves the stomach more slowly. For tirzepatide, the label says this delay is largest after the first dose and lessens over time.1,2 A 2025 joint advisory from four US nutrition and obesity societies links slower emptying to bloating, fullness and nausea, and says GLP-1s occasionally affect gut movement or secretions, contributing to diarrhea.8 The STEP authors note that changes in lower-gut transit may explain diarrhea or constipation, but that evidence is lacking.5 Why some people's burps smell of sulfur has not been studied.
What helps GLP-1 diarrhea, burping and heartburn?
There are no trials testing specific remedies for these symptoms on GLP-1s. Expert guidance, based on clinical experience, suggests:
- For diarrhea. A 2022 multidisciplinary consensus from Spain recommends generous fluids, and avoiding dairy, coffee, alcohol, soft drinks, very hot or cold foods, and sweeteners ending in "-ol" such as sorbitol. It suggests cutting back on high-fiber foods until symptoms improve, then adding fiber back gradually. If diarrhea persists despite this, it says probiotics or an antidiarrheal could be considered.7 The 2025 US advisory adds that fiber supplements can bulk the stool and antidiarrheals can give short-term relief.8
- For burping and heartburn. In a case example, the consensus suggested smaller, more frequent meals; avoiding fatty, fried or processed foods, chocolate, mint, coffee, alcohol and carbonated drinks; and not lying down soon after eating, plus a short course of acid-reducing medicine prescribed by the doctor.7 The US advisory says alcohol may worsen reflux on GLP-1 therapy.8
- Pace of dose increases. The US advisory notes that in the trials, people could stay at a dose for up to 8 weeks to let stomach side effects settle.8 Dose decisions belong to your prescriber.
Over-the-counter medicines can interact with your other medicines or hide a more serious problem, so ask your pharmacist or doctor first. Keeping up protein and fluids helps when appetite is low; see what to eat on a GLP-1.
When to get medical help
The labels' warnings section describes symptoms that need attention. This is the labels' instruction, not personal advice:
- Dehydration. Both the Wegovy and Zepbound labels report acute kidney injury, sometimes needing dialysis, mostly in people who became dehydrated from nausea, vomiting or diarrhea. Their patient guides say to drink fluids and to tell your provider right away if nausea, vomiting or diarrhea does not go away.1,2
- Severe or persistent belly pain. Pain that is severe or will not go away, sometimes spreading to the back, with or without vomiting, can be a sign of acute pancreatitis. The labels say the medicine should be stopped if pancreatitis is suspected. See GLP-1 gallbladder and pancreatitis risks.1,2
- Severe stomach side effects. These were reported by 4.1% on Wegovy 2.4 mg vs 0.9% on placebo, and by 1.7% to 3.1% on Zepbound vs 1% on placebo. Both labels say the drugs are not recommended for people with severe gastroparesis.1,2
Common questions
How long does GLP-1 diarrhea last?
In the STEP 1 to 3 trials of semaglutide 2.4 mg (Wegovy) in adults with overweight or obesity, the median diarrhea episode lasted 3 days. The Wegovy and Zepbound labels say most diarrhea happened during dose escalation and decreased over time.
Do Zepbound, Wegovy and Mounjaro cause sulfur burps?
The US labels list burping (eructation) as a side effect: 7% on Wegovy 2.4 mg vs under 1% on placebo, and 4% to 5% on Zepbound vs 1% on placebo, in weight-loss trials. No trial has measured whether burps smell of sulfur, so sulfur burps is an informal term with no published data behind it.
Can GLP-1 medicines cause heartburn?
Yes. In weight-loss trials, gastroesophageal reflux disease was reported by 5% on Wegovy 2.4 mg vs 3% on placebo, and indigestion (dyspepsia) by 9% vs 3%. On Zepbound 15 mg, reflux was 5% vs 2% and dyspepsia 10% vs 4%.
What helps GLP-1 diarrhea?
A 2022 expert consensus advises generous fluids, avoiding foods such as dairy, coffee, alcohol, soft drinks and sugar alcohols, and says an antidiarrheal could be considered if diarrhea persists. In the SURMOUNT-1 to -3 trials, 5.2% to 9.3% of people on tirzepatide used an antidiarrheal medicine, vs 1.2% to 2.2% on placebo. Ask your care team before taking anything.
When is diarrhea on a GLP-1 serious?
The Wegovy and Zepbound labels warn that diarrhea, nausea and vomiting can cause dehydration leading to kidney problems, and to tell your provider right away if they do not go away. Severe or persistent stomach pain, sometimes spreading to the back, can be a sign of pancreatitis and needs prompt medical attention.
Sources
- WEGOVY (semaglutide) US prescribing information, sections 5.2, 5.5, 5.6, 6.1 and Medication Guide. DailyMed (revised June 2026, checked November 2026).
- ZEPBOUND (tirzepatide) US prescribing information, sections 5.2, 5.3, 5.5, 6.1, 12.2 and Medication Guide. DailyMed (revised August 2026, checked November 2026).
- OZEMPIC (semaglutide) US prescribing information, section 6.1. DailyMed (revised June 2026, checked November 2026).
- MOUNJARO (tirzepatide) US prescribing information, section 6.1. DailyMed (revised August 2026, checked November 2026).
- Wharton S, Calanna S, Davies M, et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss. Diabetes Obes Metab. 2022;24(1):94-105. doi:10.1111/dom.14551 · Full text (PMC)
- Rubino DM, Pedersen SD, Connery L, et al. Gastrointestinal tolerability and weight reduction associated with tirzepatide in adults with obesity or overweight with and without type 2 diabetes in the SURMOUNT-1 to -4 trials. Diabetes Obes Metab. 2025;27(4):1826-1835. doi:10.1111/dom.16176 · Full text (PMC)
- Gorgojo-Martínez JJ, Mezquita-Raya P, Carretero-Gómez J, et al. Clinical Recommendations to Manage Gastrointestinal Adverse Events in Patients Treated with Glp-1 Receptor Agonists: A Multidisciplinary Expert Consensus. J Clin Med. 2022;12(1):145. doi:10.3390/jcm12010145 · Full text (PMC)
- Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity (Silver Spring). 2025;33(8):1475-1503. doi:10.1002/oby.24336 · Full text (PMC)
