Does Ozempic Cause Diarrhea, and How Long Does It Last?

The short answer: Yes. Diarrhea is one of the most common side effects of Ozempic. In the label's placebo-controlled diabetes trials, it affected 8.5% of people on 0.5 mg and 8.8% on 1 mg, versus 1.9% on placebo. Most episodes are mild, start during dose increases, and last about 3 days each. Diarrhea that does not stop needs a call to your doctor, because fluid loss can harm the kidneys.

How common is diarrhea on Ozempic?

The FDA prescribing information for Ozempic lists diarrhea among the five most common adverse reactions, with nausea, vomiting, abdominal pain, and constipation. Its Table 1 pools placebo-controlled trials in adults with type 2 diabetes:

• Placebo: 1.9% reported diarrhea.
• Ozempic 0.5 mg: 8.5% reported diarrhea.
• Ozempic 1 mg: 8.8% reported diarrhea.

Across all stomach and bowel complaints, the same trials showed 15.3% on placebo, 32.7% on 0.5 mg, and 36.4% on 1 mg. In a separate trial of 1 mg versus 2 mg, gastrointestinal reactions occurred in 30.8% and 34% of patients. The label does not give a separate diarrhea rate for the 2 mg dose.

Rates are higher at weight-loss doses. Wegovy contains the same drug, semaglutide, at up to 2.4 mg weekly. In the Wegovy label, 30% of adults on the 2.4 mg injection reported diarrhea, versus 16% on placebo. Note how high the placebo rate is. Some diarrhea in any trial comes from ordinary causes like infections and food, not the drug.

Why does semaglutide cause diarrhea?

Semaglutide is a GLP-1 receptor agonist. It acts on receptors throughout the digestive tract, and the Ozempic label states that it delays gastric emptying. Changes in how fast food and fluid move through the gut can push stools in either direction. That is why some people get diarrhea while others get constipation, and some get both at different times.

Diet can add to it. Many people change how they eat when they start Ozempic. Large or fatty meals, sugar alcohols, and very sweet drinks can all loosen stools on their own. The NIDDK diet guidance for diarrhea lists high-fat foods, caffeine, alcohol, and sugar alcohols as things that can make diarrhea worse.

When does it start, and how long does each episode last?

The Ozempic label says the majority of reports of nausea, vomiting, and diarrhea occurred during dose escalation. Ozempic starts at 0.25 mg weekly for 4 weeks, then rises to 0.5 mg. Each later step up (to 1 mg or 2 mg) comes after at least 4 more weeks. Each increase is a common time for symptoms to return.

The label does not state how long diarrhea lasts. The best duration data come from the weight-loss trials. A 2022 pooled analysis of the STEP 1 to 3 trials in Diabetes, Obesity and Metabolism looked at 2,117 adults on semaglutide 2.4 mg and 1,262 on placebo. Its full text reports these findings:

• The median duration of a diarrhea episode was 3 days, similar to placebo.
• Nausea episodes lasted a median of 8 days and vomiting 2 days.
• How often people had diarrhea, nausea, and vomiting peaked at about week 20 (near the end of dose escalation), then declined.
• 98.1% of gastrointestinal events were mild to moderate, and 99.5% were non-serious.

Two cautions apply. These numbers come from the higher Wegovy dose in people without diabetes, so they are a guide, not a promise for Ozempic. And the rates stayed above placebo for the whole 68 weeks, so a smaller group of people still had episodes long after escalation ended.

Can diarrhea on Ozempic become dangerous?

Usually it does not, but there is one specific risk to know about. The Ozempic label carries a warning for acute kidney injury due to volume depletion. It reports postmarketing cases of kidney injury, some needing dialysis. Most occurred in people who became dehydrated from nausea, vomiting, or diarrhea. The label tells prescribers to monitor kidney function in patients reporting these reactions.

The label also lists severe gastrointestinal reactions as a warning. In Ozempic trials, they occurred in 0.4% of people on 0.5 mg and 0.8% on 1 mg, versus 0% on placebo. The MedlinePlus semaglutide page also asks patients to tell their doctor before treatment about recent diarrhea or vomiting, or if they cannot drink liquids. People with existing kidney disease have the most to lose from dehydration. Our guide to Ozempic and kidney problems covers that risk in more detail.

What helps while it lasts?

The patient information in the Ozempic label says it is important to drink fluids to reduce the chance of dehydration. General NIDDK advice on treating acute diarrhea adds practical steps:

• Replace fluids and electrolytes. Drink water plus liquids with electrolytes, such as broths, sports drinks, or oral rehydration solutions.
• Eat normally when you feel able. NIDDK says most people with acute diarrhea can return to their usual diet.
• Limit common triggers. Alcohol, caffeine, fried and fast food, lactose, and sugar-free sweets with sugar alcohols can worsen symptoms.
• Keep meals smaller. Smaller portions are easier on a slowed stomach and may reduce other GI side effects too.

Ask your prescriber or pharmacist before using an over-the-counter anti-diarrheal, especially if you have diabetes, kidney disease, fever, or bloody stools. If diarrhea keeps returning after each dose increase, ask whether you can stay at your current dose longer. Do not change your dose on your own. For nausea and constipation, see our guide to managing Ozempic side effects.

Semaglutide is not unique here. Diarrhea is a class-wide effect of GLP-1 drugs, and glp1.md compares how the medicines in this group differ.

When should you call a doctor?

The Ozempic label tells patients to contact their healthcare provider right away for nausea, vomiting, or diarrhea that does not go away. The NIDDK symptom guidance says adults should talk with a doctor right away for:

• Diarrhea lasting more than 2 days.
• Six or more loose stools in a day.
• High fever or frequent vomiting.
• Black, tarry stools, or stools with red blood or pus.
• Severe pain in the abdomen or rectum, or a change in mental state.
• Signs of dehydration: extreme thirst, dry mouth, urinating less than usual, dark urine, or feeling dizzy or lightheaded.

Severe belly pain that will not go away, sometimes felt through to the back, is a different concern. It can signal pancreatitis. The label tells patients to stop Ozempic and call their provider right away. Diarrhea can also coincide with low blood sugar if you take insulin or a sulfonylurea and are eating less.

The bottom line

Ozempic causes diarrhea in about 1 in 11 people at diabetes doses, and in more people at the higher Wegovy dose. Most episodes are mild, cluster around dose increases, and last about 3 days. The real risk is dehydration, which can injure the kidneys. Drink fluids, ease off trigger foods, and call your doctor if diarrhea persists past 2 days or you show signs of dehydration.

Last updated: October 2026. This article is for informational purposes only and does not constitute medical advice. Talk with your prescriber before changing your Ozempic dose or starting any medicine for diarrhea.