Sulfur Burps on a GLP-1: Why They Happen and What Got Rid of Mine

Nobody warned me about this one

I was ready for nausea. I had crackers in the car and everything. What I was not ready for was standing in my kitchen on a Tuesday, burping, and tasting something that can only be described as rotten eggs.

I want to be honest about the first thing I felt, which was not curiosity. It was embarrassment. I did not want to type it into a search bar and I definitely did not want to say it out loud at a school pickup. So if that is where you are right now — hi. It has a name, it is on the label, and there are things that helped me.

The usual boundary: I am a mom who walked these signups, not a clinician. This is education from published research and the FDA labels, not medical advice.

It is on the label. It has a name.

The clinical word is eructation. That is just belching, written the way a drug label writes it — and the patient-facing version of the Wegovy label says "belching" in plain English, so even the manufacturer switches to the normal word when it is talking to us.

Here is what made me feel least like a weirdo. In the Wegovy trials, eructation was reported by 7% of people taking it, against under 1% on placebo¹. For tirzepatide it runs around 3% versus 0.4% on placebo². Those are not rounding errors. Seven percent of a very large trial is a lot of people burping in a lot of kitchens, and almost nobody writes about it.

Gastrointestinal side effects generally are the most common thing these drugs do to you — a systematic review and meta-analysis of GLP-1 receptor agonists found GI adverse events to be the dominant safety signal across trials³. Burping is simply the one that does not get a paragraph in the welcome email.

Why it smells like *that*

Two things are happening, and understanding them is what stopped me feeling like something had gone badly wrong.

One: everything is moving slower. These medicines delay how fast your stomach empties — that is a core part of how they work, and it is well described in the clinical literature on GLP-1 receptor agonists and tirzepatide⁴. Food and gas that used to move along now sit longer.

Two: the smell is sulfur, and sulfur comes from protein. The rotten-egg note is hydrogen sulfide. Your gut bacteria make it by breaking down sulfur-containing amino acids — cysteine in particular — and microbial cysteine degradation is a dominant route for hydrogen sulfide production in the gut⁵. Put those together: more time sitting, more bacterial work on sulfur-rich protein, more of that specific smell coming back up.

Which, annoyingly, means the exact thing many of us are told to eat more of on a GLP-1 — protein, to hold onto muscle — is also the thing feeding the smell. That tension is real and nobody mentioned it to me.

What actually helped me

None of this is a prescription. It is the boring practical stuff, roughly in the order it made a difference:

• Splitting my protein up. I was doing what I had been told and front-loading a large protein hit in one sitting. Spreading the same amount across the day was the single biggest change for me. I did not eat less protein — I stopped delivering it in one lump.
• Noticing which proteins. For me the worst days followed eggs and a lot of red meat. Both are high in sulfur-containing amino acids. I did not eliminate anything; I just stopped stacking them on the same day.
• Smaller meals, more often. With a stomach that empties slowly, a big meal is a long queue. Smaller ones cleared faster.
• Not lying down after eating. Obvious in hindsight. Less obvious at 9pm on the sofa.
• Timing it around the shot. Mine were worst in the two or three days after my injection and after every dose increase, which matches how the rest of the GI stuff behaves.

For belching that will not settle, the American Gastroenterological Association published a clinical practice update on evaluating and managing belching, bloating and distention — worth knowing it exists, because it means this is a real thing clinicians have a real framework for, not something you have to just tolerate⁶.

When to stop troubleshooting and call

This is the part I want you to actually read.

Burping on its own is unpleasant, not dangerous. But sulfur burps arriving together with severe or worsening abdominal pain, persistent vomiting, a swollen or hard belly, or an inability to keep fluids down are not a "try smaller meals" situation. Those are call-your-clinician-today symptoms, because the same slowed-down gut that causes the burps sits behind the more serious gut complications these labels warn about¹.

I held out for four days once because it felt too silly to call about burping. Do not be me. "It smells like sulfur and I feel awful" is a completely legitimate reason to message your provider.

The part that is about who you signed up with

Here is where this connects to the thing I actually spend my time on. Sulfur burps flare hardest around a dose increase — and what you want, at exactly that moment, is a provider who will answer you and slow your titration down.

Some programs do that. Some send you into a portal that nobody reads for four days. That responsiveness is a real part of how I score providers on the Mom-Tested Score methodology, and it is a big reason CoreAge Rx sits where it does on my list — you can hold a dose without a fight. If you want the wider picture, I keep the full honest list of side effects, the constipation piece that covers the other end of the same slowed-down gut, and what nobody told me about the women-specific effects.

One more time, plainly: this is educational, not medical advice, and these medicines are not for use in pregnancy or while trying to conceive. Your plan belongs to you and your own clinician.