The short answer
Usually yes. No GLP-1 label lists simethicone (Gas-X) or bismuth subsalicylate (Pepto-Bismol) as an interaction. Gas-X is the gentle one: MedlinePlus says it usually has no side effects. Pepto has more caveats: it contains salicylate, the aspirin family, its box says to ask first if you take a diabetes or blood thinner drug, it can turn stool black, and it is meant for 2 days at most.
At GLP-1 SOS, the burping, gas and fullness of the first months send a lot of people to the pharmacy aisle, and these are the two boxes they pick up most. They do different jobs. Here is what each label says and where the caveats sit on a GLP-1. For the fixes that do not come in a box, see how to get rid of bloating on a GLP-1.
At a glance
Three things to know
1
Gas-X for pressure
Simethicone is labeled for gas pressure, bloating and fullness. It has no listed interactions and usually no side effects.
2
Pepto for an upset gut
Bismuth subsalicylate is labeled for diarrhea and an upset stomach, including nausea, gas and belching. It is not for a constipated week.
3
Read Pepto’s box
It contains salicylate. Ask first if you take a diabetes drug, a blood thinner, or medicine for gout or arthritis.
What each one actually does
A GLP-1 slows the stomach, so food and swallowed air sit longer. That shows up as burping, fullness and gas: in Wegovy trials, 7% of people reported burping versus under 1% on placebo, with more bloating and flatulence too. Some of it is normal for anyone; the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) notes people typically belch up to 30 times a day and that passing gas up to 25 times a day is considered normal. More on the patterns in gas and burping on a GLP-1.
Simethicone, the ingredient in Gas-X, is an antigas medicine labeled for the relief of pressure, bloating and fullness. The Gas-X Extra Strength label says 1 or 2 softgels of 125 mg after meals and at bedtime, and no more than 4 in 24 hours without a doctor’s advice. MedlinePlus says that, taken as directed, it usually has no side effects. It will not speed a slow stomach or move a backed-up colon, but for trapped-gas pressure it is the low-risk first try.
Lab note
Gas-X is the gentle tool for gas. Pepto is a real medicine with a salicylate in it, and its box deserves a full read.
Pepto-Bismol is bismuth subsalicylate, 525 mg per 30 mL dose, and that dose carries 261 mg of salicylate. It is labeled for diarrhea and for upset stomach from overindulgence, including heartburn, indigestion, nausea, gas, belching and fullness. MedlinePlus says it works partly by reducing the flow of fluid into the bowel, which helps loose stools but is the wrong direction on a constipated week. Bismuth also binds sulfur: in a small 1998 study of 10 healthy adults, it cut hydrogen sulfide released from stool by more than 95%. That is the rotten-egg gas behind sulfur burps, though the study measured stool, not burps.
The caveats are on the box. Do not use it if you are allergic to salicylates, including aspirin, or have an ulcer, a bleeding problem, or bloody or black stools. Ask a doctor or pharmacist first if you take a drug for diabetes, blood thinning, gout or arthritis, which matters if your GLP-1 is Ozempic or Mounjaro for type 2 diabetes. It can turn your tongue and stool dark, which is harmless but can hide a real warning sign. Stop and ask a doctor if symptoms last more than 2 days or your ears ring.
From the labels and studies
The numbers that matter
7%
of adults on Wegovy injection reported burping in trials, versus under 1% on placebo (Wegovy label)
8 doses
is the most Pepto-Bismol liquid allowed in 24 hours (240 mL), for no more than 2 days (Pepto-Bismol label)
95%+
drop in hydrogen sulfide released from stool after bismuth subsalicylate, in 10 healthy adults (Gastroenterology, 1998)
Sources: Wegovy Prescribing Information, June 2026; Pepto-Bismol Drug Facts, DailyMed, March 2026; Suarez et al., Gastroenterology, 1998.
What to do
- Match the product to the problem. Pressure and trapped gas: simethicone. Loose stools or an upset stomach after a heavy meal: Pepto, short term. Hard stools and no bowel movement: neither; treat the constipation first.
- Start with simethicone. Follow the box, for example 1 or 2 softgels of 125 mg after meals and at bedtime, no more than 4 a day for Gas-X Extra Strength. A gentle walk after meals helps too.
- Check before reaching for Pepto. Skip it if you are allergic to aspirin, have an ulcer or a bleeding problem, or your stool is already black or bloody. Ask your pharmacist first if you take a diabetes drug, a blood thinner, a daily aspirin, or gout or arthritis medicine.
- Keep Pepto short. No more than 8 doses in 24 hours and no more than 2 days. If you are using it for diarrhea, drink clear fluids alongside; for an alternative, see whether Imodium fits with a GLP-1.
- Mind the timing with oral GLP-1s. If you take the Wegovy pill or Rybelsus, take it first with a little water and wait the full 30 minutes before any other medicine, Gas-X and Pepto included.
- Keep a calm daily routine underneath. Smaller meals, slower eating, fewer fizzy drinks and sugar alcohols. If you take GLP-1 SOS Daily Gut Relief, keep 2 capsules with dinner: ginger root and peppermint support digestive comfort and a 19-strain probiotic blend supports the gut through the slow weeks. It is daily support, not a rescue for a bad night.*
*GLP-1 SOS Daily Gut Relief supports regular bowel movements and digestive comfort. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Two kinds
Fine to treat at home, or a same-day call
Usually expected
- Burping and fullness after meals
- Gas and rumbling, worse after certain foods
- Sulfur-smelling burps now and then
- Dark tongue or stool for a day or two after Pepto
Call the same day
- Severe or lasting belly pain, sometimes into the back
- Vomiting with a swollen belly and no gas
- Black or bloody stool you cannot explain by Pepto
- Ringing in the ears after Pepto
Gas and fullness are common. Pain, blood or a blocked belly are not a job for the pharmacy aisle.
When to call your doctor
Call your prescriber the same day, or get urgent care, if:
- You have severe or lasting belly pain, sometimes spreading to your back, with or without vomiting
- You are vomiting and your belly is swollen, or you cannot pass gas or stool
- You see bloody or black, tarry stools you cannot explain by Pepto
- You notice ringing in your ears or hearing changes after taking Pepto
- You have upper right belly pain with fever, or yellow skin or eyes
- You take insulin or a sulfonylurea and feel shaky, sweaty or confused
Gas is uncomfortable but usually harmless. Pain, blood or a belly that will not pass gas needs a doctor, not another dose.
From the people behind the Lab
You do not have to figure this out alone.
GLP-1 SOS is the daily companion made for life on a GLP-1. Plain answers like this one, a support team that replies to real questions from real people, and daily formulas like GLP-1 SOS Daily Gut Relief, designed around the side effects that come with the medication. The GLP-1 Lab is our free education arm: no login, no paywall, no hype. Side effects are part of the road. Suffering through them is not.
Questions people also ask
Can I take Gas-X with Ozempic or Wegovy?
Yes, for most adults. Neither the Ozempic nor the Wegovy label lists simethicone as an interaction, and MedlinePlus says it usually has no side effects when taken as directed. Use it for gas pressure and fullness, following the box limit, such as no more than 4 softgels a day for Gas-X Extra Strength. If bloating comes with pain or vomiting, call instead.
Is Pepto-Bismol safe on Mounjaro or Zepbound?
For short use, usually, but read the box. Pepto contains salicylate, so skip it if you are allergic to aspirin or have an ulcer or a bleeding problem. The label says to ask a doctor or pharmacist first if you take a diabetes drug or a blood thinner, which includes Mounjaro used for type 2 diabetes. Limit it to 2 days.
Does Pepto help sulfur burps on a GLP-1?
It may. Bismuth binds hydrogen sulfide, the rotten-egg gas, and in a small 1998 study it cut hydrogen sulfide released from stool by more than 95%. That study did not measure burps, so take it as a reasonable short-term option, not a proven fix. Sulfur burps with vomiting or diarrhea that will not stop need a call.
Why is my stool black after Pepto?
Bismuth can turn the tongue and stool dark, and the Pepto label calls this temporary and harmless. The catch is that black, tarry stool can also mean bleeding, which is why the label says not to use Pepto if your stool is already black or bloody. If it stays black after you stop, or you feel faint, call.
Which is better for GLP-1 bloating, Gas-X or Pepto?
For gas pressure and fullness, Gas-X is the simpler, gentler choice. Pepto fits an upset stomach with loose stools after a heavy meal, and it is the wrong pick when you are constipated, because it reduces fluid in the bowel. If bloating comes with no bowel movement for days, treating the constipation will help more than either.
Sources (7)
- Gas-X Extra Strength softgels (simethicone 125 mg), Drug Facts label. DailyMed, U.S. National Library of Medicine.
- Simethicone. MedlinePlus Drug Information, National Library of Medicine.
- Pepto-Bismol (bismuth subsalicylate) suspension, Drug Facts label. DailyMed, U.S. National Library of Medicine, updated March 2026.
- Bismuth Subsalicylate. MedlinePlus Drug Information, National Library of Medicine.
- Suarez FL, et al. Bismuth subsalicylate markedly decreases hydrogen sulfide release in the human colon. Gastroenterology, 1998.
- Symptoms & Causes of Gas in the Digestive Tract. NIH National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
- Wegovy (semaglutide) injection and tablets, Prescribing Information. Novo Nordisk / FDA, revised June 2026.
Reviewed by the GLP-1 SOS editorial team · Education, not medical advice · Talk to your prescriber about your dose and your symptoms.
