Guides / Side effects and results

GLP-1 sulfur burps: how common, and what's known

Burping is on every GLP-1 label, but none of them say anything about the smell.

By PeptideTracker editorial team · Updated November 8, 2026 · 8 sources

[00] Short answer

  1. Burping (eructation) was reported by 7% of adults on Wegovy 2.4 mg vs under 1% on placebo1.
  2. On Zepbound it was 4–5% vs 1% on placebo, and on Foundayo 6–8% vs 1%2–3.
  3. In the diabetes trials it was lower: 2.5–3.3% on Mounjaro vs 0.4%, and 1.1–2.7% on Ozempic vs 0%4–5.
  4. No label or trial counts "sulfur" burps separately. The labels list all burping under one term, so how many people get the eggy smell isn't known.
  5. The labels say these medicines slow how fast the stomach empties. Researchers say that may play a part in stomach side effects, but the cause isn't proven1,7.

How common are burps on Wegovy, Zepbound and Mounjaro?

Burping is one of the less common stomach side effects. In the weight-loss trials it was reported by 7% of adults on Wegovy 2.4 mg, 4% to 5% on Zepbound and 6% to 8% on Foundayo, with 1% or fewer on placebo1–3. For comparison, nausea on the same labels runs from 25% to 44%. The GLP-1 side effects guide has those numbers.

Percent of adults reporting burping, reflux and bloating (US labels, section 6.1)
GroupBurping (eructation)Reflux (GERD)Bloating (abdominal distension)
Wegovy placebo1<1%3%5%
Wegovy 2.4 mg weekly17%5%7%
Zepbound placebo21%2%2%
Zepbound 5 mg24%4%3%
Zepbound 10 mg25%4%3%
Zepbound 15 mg25%5%4%
Foundayo placebo31%2%3%
Foundayo 5.5 mg daily36%6%7%
Foundayo 9 mg daily38%6%9%
Foundayo 17.2 mg daily38%7%8%
Mounjaro placebo (diabetes)40.4%0.4%0.4%
Mounjaro 5 mg43.0%1.7%0.4%
Mounjaro 10 mg42.5%2.5%2.9%
Mounjaro 15 mg43.3%1.7%0.8%
Ozempic placebo (diabetes)50%0%–
Ozempic 0.5 mg52.7%1.9%–
Ozempic 1 mg51.1%1.5%–

Wegovy: 68-week weight trials, Table 3. Zepbound and Foundayo: 72-week weight trials, Table 1. Mounjaro and Ozempic: type 2 diabetes trials, rates listed under Table 11–5. "–" means the label doesn't list it. Compare each medicine with its own placebo row.

The labels warn that rates from one drug's trials can't be directly compared with another's1–2. The trials enrolled different people for different lengths of time, so each medicine has its own placebo row. Burping rises only a little with dose, if at all: on Foundayo it went from 6% to 8%, and on Zepbound from 4% to 5%.

UK note: the UK Mounjaro SmPC lists burping (eructation) as "common", which means between 1 in 100 and 1 in 10 people8.

Are sulfur burps a listed side effect of GLP-1s?

Not by that name. The prescribing information for Wegovy, Zepbound, Foundayo, Mounjaro and Ozempic lists "eructation", the medical word for burping, and the Wegovy Medication Guide calls it "belching"1–5. None of them describe a smell or taste.

So the label numbers above cover every kind of burp. Nobody has published how many of those were the eggy, sulfur-smelling kind, and no trial we found measured the gases involved. Sulfur burps on GLP-1s are widely talked about, but they haven't been studied as their own side effect.

Why do GLP-1 medicines cause burping?

The exact reason isn't known. What the labels do say is that semaglutide, tirzepatide and orforglipron all slow down how fast food leaves the stomach (delayed gastric emptying)1–3. A review in the Journal of Clinical Endocrinology and Metabolism adds that GLP-1 medicines also slow movement through the small intestine6.

  • The slowing fades. The Zepbound and Foundayo labels say the delay in stomach emptying is largest after the first dose and gets smaller over time2–3. The same review describes this fading (tachyphylaxis) with long-term use6.
  • The link to stomach side effects isn't settled. The authors of a pooled analysis of the semaglutide 2.4 mg trials wrote that the mechanism behind GLP-1 stomach side effects "remains uncertain". They said delayed emptying may contribute, but that a 20-week study of semaglutide 2.4 mg didn't find a delay using their test7.
  • No label links burping to slow emptying. The labels list both facts in different sections. Joining them up is a reasonable guess, not something a trial has shown.

Do GLP-1 burps go away?

The labels don't say how long burping lasts. They only give timing for nausea, vomiting and diarrhea. On Zepbound, Mounjaro and Foundayo, those mostly happened while the dose was going up and decreased over time2–4.

Whether burping follows the same pattern hasn't been reported. Because the slowing of stomach emptying is biggest early and fades2–3, some people expect burping to ease too. That's plausible, but it hasn't been measured.

When is burping on a GLP-1 a reason to call your doctor?

Burping on its own isn't one of the warning signs the labels list. The Wegovy Medication Guide says to tell your healthcare provider about stomach problems that are severe or won't go away1, and the Zepbound label gives prescribers the same instruction to pass on2.

  • Severe stomach pain that won't go away, with or without vomiting, sometimes reaching your back: the Wegovy Medication Guide says to stop the medicine and call your provider right away1.
  • Vomiting or diarrhea that won't stop: fluid loss can lead to kidney problems, and the Medication Guide says to tell your provider right away1.
  • Before surgery or sedation: because these medicines slow stomach emptying, tell the team you take one1–2.

Questions

How common are burps on Wegovy?

In the Wegovy 2.4 mg weight-loss trials, 7% of adults reported burping (eructation), compared with under 1% on placebo. In the trial in children aged 12 and over, it was 4% vs 0%.

Does Zepbound cause sulfur burps?

The Zepbound label lists burping in 4% of adults on 5 mg and 5% on 10 mg or 15 mg, vs 1% on placebo. It doesn't say anything about smell, so how many of those were sulfur burps isn't known.

Can Ozempic or Mounjaro cause burping?

Yes, both labels list it. In the type 2 diabetes trials, burping was reported by 2.7% on Ozempic 0.5 mg and 1.1% on 1 mg vs 0% on placebo, and by 2.5% to 3.3% on Mounjaro vs 0.4% on placebo.

Do GLP-1 burps get better over time?

It hasn't been measured for burping. The labels say nausea, vomiting and diarrhea mostly happen during dose increases and decrease over time, and the Zepbound and Foundayo labels say the slowing of stomach emptying is largest after the first dose.

Is burping worse on a higher dose?

Only a little, if at all. On Zepbound it was 4% at 5 mg and 5% at 10 mg and 15 mg, and on Foundayo 6% at 5.5 mg and 8% at 9 mg and 17.2 mg. On Mounjaro it was 3.0%, 2.5% and 3.3% at 5, 10 and 15 mg, and on Ozempic 2.7% at 0.5 mg and 1.1% at 1 mg.

Sources

Checked against Wegovy, Zepbound, Foundayo, Mounjaro and Ozempic US prescribing information (2026), the UK Mounjaro SmPC (August 2026), and peer-reviewed reviews in J Clin Endocrinol Metab and Diabetes Obes Metab. How we check

  1. 1Wegovy (semaglutide) injection and tablets, US prescribing information and Medication Guide, sections 5.6, 6.1, 7, 12.2 and 17. Novo Nordisk, revised 06/2026; Tables 3 and 5
  2. 2Zepbound (tirzepatide) US prescribing information, sections 5.2, 6.1, 12.2 and 17. Eli Lilly, revised 08/2026; Table 1
  3. 3Foundayo (orforglipron) tablets, US prescribing information, sections 6.1 and 12.2. Eli Lilly, revised 07/2026; Table 1
  4. 4Mounjaro (tirzepatide) US prescribing information, section 6.1. Eli Lilly, revised 08/2026; text under Table 1
  5. 5Ozempic (semaglutide) injection, US prescribing information, section 6.1. Novo Nordisk, revised 05/2026; text under Table 1
  6. 6Jalleh RJ, et al. Clinical consequences of delayed gastric emptying with GLP-1 receptor agonists and tirzepatide. J Clin Endocrinol Metab 2024;110(1):1-15. doi:10.1210/clinem/dgae719; abstract
  7. 7Wharton S, et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity. Diabetes Obes Metab 2022;24:94-105. doi:10.1111/dom.14551; discussion section
  8. 8Mounjaro KwikPen, UK Summary of Product Characteristics, section 4.8. Eli Lilly, revised 29 August 2026; accessed 8 Nov 2026

This guide explains what labels and published studies say. It isn't medical advice and doesn't replace your prescriber or pharmacist.

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