Drug facts

Semaglutide and diarrhea

By David Chen·Editor·Reviewed September 2026

How common it was on Wegovy¹

Diarrhea is second in the label’s table of reactions reported in 2% or more of participants, behind nausea at 44%. The arm was 2,116 adults on semaglutide 2.4 mg against 1,261 on placebo, across three trials of up to 68 weeks.

The placebo row is unusually high. About one participant in six reported diarrhea without the drug, so the part semaglutide added is 14 in 100, not 30. The label adds that its gastrointestinal reactions were most often reported during dose escalation, the months spent climbing the four-week steps.

Few people stopped because of it. Diarrhea led 0.7% of the semaglutide group to discontinue treatment, against 0.1% on placebo. That compares with 1.8% for nausea and 1.2% for vomiting.

How common it was on Ozempic²

The Ozempic label reports its common reactions from two placebo-controlled trials in adults with type 2 diabetes, at 0.5 mg and 1 mg:

The Ozempic figures are far lower than Wegovy’s, and they should not be read as a dose-response curve. The doses differ, the people differ (type 2 diabetes against obesity without it), and so do the trials and the placebo rates. Neither label compares its numbers with the other’s. The Ozempic label also says the majority of nausea, vomiting and diarrhea reports came during dose escalation. How the two approvals differ →

At other doses¹

The label carries a second table for the 7.2 mg dose, built from two 72-week trials. It lists only the reactions reported more often at 7.2 mg than at both 2.4 mg and placebo, and diarrhea is not one of its ten rows. For the 25 mg tablet, the label says the types and frequency of common reactions were similar to the 2.4 mg injection table.

When it becomes a kidney question³

Section 5.5 of the label is a warning about acute kidney injury due to volume depletion. It reports postmarketing cases of acute kidney injury, some requiring hemodialysis, and says the majority occurred in people who had gastrointestinal reactions leading to dehydration, naming nausea, vomiting and diarrhea. It tells prescribers to monitor kidney function in people reporting those reactions, especially while the dose is being started and raised.

In the weight-reduction trials, acute kidney injury occurred in 7 adults on semaglutide (0.4 cases per 100 patient-years) against 4 on placebo (0.2). The label says some cases came with gastrointestinal reactions or dehydration, that the risk was higher in people with a history of kidney impairment, and that it occurred more often during dose titration. Low blood pressure and fainting were also reported more often on semaglutide, and the label ties some of those to gastrointestinal reactions and volume loss.

Severe gastrointestinal reactions³

Section 5.6 is a separate warning. Severe gastrointestinal reactions were reported by 4.1% of adults on the Wegovy injection against 0.9% on placebo, and by 2% on the tablet against 0% on placebo. The Ozempic label reports 0.4% at 0.5 mg and 0.8% at 1 mg, against 0% on placebo². Both labels say semaglutide is not recommended in people with severe gastroparesis.

The label’s other gastrointestinal warnings, on acute pancreatitis and gallbladder disease, describe different symptoms, chiefly abdominal pain that is severe or will not go away.

What the label tells patients⁴

The Medication Guide, the part of the label written for the person taking the drug, lists “dehydration leading to kidney problems” among its serious side effects, in these words:

Diarrhea, nausea, and vomiting may cause a loss of fluids (dehydration) which may cause kidney problems. It is important for you to drink fluids to help reduce your chance of dehydration. Tell your healthcare provider right away if you have nausea, vomiting, or diarrhea that does not go away.

That is the whole of the label’s instruction on the subject. It gives no list of foods, medicines or amounts, and this page does not add one.

What none of this covers

Nothing here is medical advice, and this page deliberately suggests no remedy. Whether a side effect needs managing, and how, is a question for the prescriber. The full table of reported reactions is on side effects, and constipation, the reaction often reported alongside this one, has its own page. See the medical disclaimer.