Diarrhea on Ozempic: how long, and what to do

The other end of the same problem

I have a guide on constipation on Ozempic and Wegovy, and this is its sister: the same medication, the same gut, and many women pass through both extremes in different weeks. In the semaglutide trials at the Wegovy dose, 30% of participants reported diarrhea, against 16% on placebo, and 24% constipation¹. Ozempic uses lower doses of the same semaglutide, so the number is likely lower — but the pattern is the same.

Why it happens is no mystery: the medication changes the pace of the whole digestive tract. The stomach empties more slowly, and the gut, depending on the week and what you ate, can run too slow or too fast. Neither one means something is wrong with you.

How long it lasts

Like nausea, diarrhea clusters around dose increases: the label reports digestive reactions most frequently during escalation¹, and the pooled analysis of three trials describes them as transient, overwhelmingly mild or moderate (98%), and concentrated during or shortly after each step up². Days is typical, not weeks. On the label, diarrhea was the reason only 0.7% of participants discontinued¹.

And the figure worth keeping: the women who had digestive effects lost about the same weight as the women who didn't; less than one percentage point of the loss was explained by them². A bad gut week is not "doing the work" for you. The medication does it either way.

What helps

1. 1.Fluids, with salts. With diarrhea you lose water and minerals together. Plain water sometimes isn't enough: broth, an electrolyte drink, or an oral rehydration solution from the pharmacy. In sips, all day.
2. 2.Small, simple meals for a few days: rice, tortillas, skinless chicken, banana, oatmeal. Save the very greasy, very spicy and very sweet for later — those are the three that speed the gut up most at this stage.
3. 3.Watch the "sugar-free." Many products sweetened with sugar alcohols (sorbitol, maltitol) loosen the gut on their own; with Ozempic on top, more so.
4. 4.Don't rush the next dose. If the diarrhea arrived with the last increase, staying a step longer is a normal option; the 2026 meta-analysis on escalation shows that longer schedules with more steps build more tolerance to digestive effects³. Ask rather than decide alone — but do ask.
5. 5.Anti-diarrheals, only with the okay. A medication that slows the gut on top of one that already slows it is a combination that deserves your clinician's opinion, not a pharmacy-aisle decision.

Why it alternates with constipation

It is one of the most confusing parts: one week nothing, the next week everything. The explanation is that the medication doesn't "pick" a direction — it slows stomach emptying and changes how much you eat and drink, and the gut responds to those two changes differently from day to day. Little fiber and little water pull toward constipation; a greasy meal or a sugar-free product pulls toward diarrhea. Most women find their middle within a few weeks.

When to call today, not tomorrow

The same warning as with nausea, because the risk is the same: the semaglutide label describes cases of acute kidney injury, some needing dialysis, and most were in people dehydrated by nausea, vomiting or diarrhea¹. With a baby on your hip or three kids to get to school, it is easy not to notice how much fluid you've lost.

Call the same day if:

• The diarrhea has lasted more than two days, or there are many episodes a day and you can't keep fluids down.
• You are urinating much less, the urine is very dark, or you get dizzy standing up.
• There is blood in the stool, or it is black. That is not an expected GLP-1 side effect — it is something else, and it needs looking at.
• You have a fever, or severe abdominal pain that doesn't ease.

The full list of dehydration signs is in dehydration and your kidneys, and if the problem is more gas and bloating than diarrhea, that guide is bloating and gas.

In short

Three in ten had diarrhea in the trials; it comes with dose increases, lasts days, and almost nobody stops the medication over it. Fluids with salts, simple food, an eye on the "sugar-free," and an unhurried escalation. Blood in the stool or not keeping fluids down are not expected — they are called in.