Sulphur burps and other indignities

Nobody warns you about this bit

There is a particular message that arrives in our constipation-and-gut circle every week, always with an apology in the first line. It goes: is anyone else burping and it smells like rotten eggs, and I am so sorry to ask.

Yes. A great many of us, at some point. It is one of the most commonly reported and least documented experiences on these medicines, and the apology is the part we would like to remove. Tomás opens that thread by saying he has heard more about other people’s digestion than almost anyone alive and has made peace with it, which usually does the trick.

This guide covers the whole unglamorous set: sulphur-scented burping, ordinary burping in volume, wind, bloating, gurgling loud enough to be heard across a room, and the general sense that your abdomen has developed opinions. None of it is dangerous by itself. All of it can make you dread a meeting.

What is probably happening

Start with what is documented. Eructation — the clinical word for burping — appears in the adverse-event tables of the tirzepatide trials (SURMOUNT-1, Jastreboff, NEJM, 2022) at low single-digit percentages, more often than on placebo, and dyspepsia and abdominal distension appear across both the semaglutide and tirzepatide programmes. So burping and bloating are recognised effects of the class.

The sulphur smell specifically is not a named adverse event in any of these trials. What follows is mechanism reasoning and member experience, and we would rather flag that than dress it up.

The smell of rotten eggs is hydrogen sulphide, produced when certain gut bacteria break down sulphur-containing compounds — including the sulphur-containing amino acids that are abundant in protein-rich food. Now add the two things these medicines do: food sits in the stomach longer, and transit through the gut is slower. Slower transit means more time for fermentation, and more fermentation of sulphur-containing material means more hydrogen sulphide, some of which comes back up.

That reasoning also predicts the two patterns members actually report, which is mildly satisfying: that it is worse in the days after a dose, and that it is worse when constipation is worse. The most consistent single observation in our circles is that people who sorted out their constipation found the sulphur burps improved.

What members have tried

Member experience, no trial evidence in this setting, and people disagree about most of it.

• Deal with the constipation first. The one thing that comes up in nearly every account. See the constipation guide.
• Notice which foods precede it. Very often eggs, red meat, protein shakes, brassicas, garlic, onions, or a large quantity of dairy — the sulphur-rich end of things. We are not telling you to cut anything out; we are saying that a fortnight of noticing tells you more than any list we could write. Some members swapped one protein source for another and the problem went.
• Smaller amounts of protein spread across the day rather than a large hit in one sitting. Protein without a chore has the practical version, and getting enough protein still matters more than avoiding the burps.
• Walking after eating. Reported to help both the wind and the bloating.
• Peppermint tea, fennel, and simethicone-type preparations from the pharmacy. Mixed reports. Peppermint can worsen reflux for some people, which is an unhelpful trade.
• Less air swallowed. Eating more slowly, fewer fizzy drinks, no chewing gum, no drinking through a straw. This mostly helps ordinary burping rather than the sulphur variety.
• Reviewing supplements. Several members traced it to a specific protein powder, a multivitamin, or an MSM or garlic supplement.

Things that did not help, reported repeatedly: heroic doses of probiotics chosen at random, and cutting protein down to very little, which fixed the smell and created a worse problem.

Bloating and the noises

Distension gets less attention than it deserves. Members describe looking visibly bloated by evening, having to undo a waistband, and being asked well-meaning questions they did not want.

What helps, from circle: smaller volumes, sitting upright after eating, loose clothing, walking, and sorting the constipation, which is the answer to an embarrassing proportion of the questions on this site. Some members find carbonated drinks are the entire cause. Some find that a large volume of fluid at once is.

Gurgling and rumbling — borborygmi, if you want the word for it — is normal gut activity and does not correlate with anything worrying. It just happens to be louder when transit is slow and when the room is quiet. Tam in Glasgow started keeping her water bottle on the desk specifically so she had something to blame the noise on, which is not a medical intervention but has improved her working life.

Worth knowing: bloating that is new, persistent, and does not vary with what you eat or how your bowels are behaving is worth mentioning to a clinician, particularly if it comes with pain, appetite change beyond what the medicine explains, or any bleeding. Persistent bloating is on the list of things clinicians want to hear about rather than reassure over the phone.

The line where indignity becomes something else

Everything in this guide is uncomfortable rather than dangerous. Three exceptions, and they are worth holding on to.

Sulphur burping combined with severe abdominal pain and vomiting you cannot break is not this. That combination needs same-day assessment, because it overlaps with the presentation of pancreatitis and of obstruction. The red-flag list has the detail.

A hard, distended, painful abdomen with vomiting and no wind passing at all is an emergency, not a wind problem.

And profuse diarrhoea alongside the burping, particularly if you cannot keep fluids down, matters because of dehydration rather than because of the smell.

Short of those, this is a quality-of-life problem, and quality of life is a legitimate reason to talk to a prescriber. Members have had escalations slowed, doses held, and in a couple of cases drugs switched, on the basis of gastrointestinal symptoms that were technically minor and practically intolerable. You do not have to justify wanting to be able to sit in an open-plan office.

On not apologising

A closing note, because the apology in that weekly message is the thing this guide is really about.

These medicines act on the digestive system. It would be strange if the digestive system did not have something to say about it. There is nothing shameful in the mechanism and nothing shameful in asking, and the reason we wrote a guide with this title is so that the word appears somewhere findable and somebody at 1am realises they are not the only one.

Poppy in Leeds, who arrived for the practical bits and stayed, put it in circle better than we can: everyone is very keen to tell you about the wonderful parts and nobody mentions that you will burp like a Victorian drain in a quiet lift. We would rather be the site that mentions it.