Constipation is one of the most common side effects of GLP-1 medicines. In the trials behind the US labels, 24% of adults on Wegovy 2.4 mg (semaglutide) and 11% to 17% on Zepbound (tirzepatide) reported constipation, compared with 11% and 5% on placebo. These medicines slow how fast food moves through your gut, and eating less means less bulk. Adding fiber gradually, drinking enough and moving every day help most people; if that is not enough, ask a pharmacist or clinician about over-the-counter options. Severe belly pain with vomiting and no bowel movement or gas needs care right away.
Key takeaways
- Constipation was reported by 24% on Wegovy 2.4 mg vs 11% on placebo, and by 11% to 17% on Zepbound vs 5% on placebo, in each US label's weight-loss trials.
- At diabetes doses the rates were lower: 3.1% to 5% on Ozempic vs 1.5% on placebo, and 6% to 7% on Mounjaro vs 1%.
- On Zepbound, constipation was most common at the lowest dose: 17% at 5 mg, 14% at 10 mg and 11% at 15 mg.
- Fiber helps most when you raise it slowly and drink more as you do. US health guidance puts adult needs at about 22 to 34 grams of fiber a day, depending on age and sex.
- Regular physical activity and a regular time for the bathroom, such as after breakfast, can also help, according to the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
- Ileus (a gut that stops moving), intestinal obstruction and severe constipation with fecal impaction are listed in the post-marketing reports of the Wegovy, Ozempic, Zepbound and Mounjaro labels. Severe belly pain, vomiting, a swollen belly or no gas needs urgent care.
How common is constipation on Wegovy, Ozempic, Zepbound and Mounjaro?
Anywhere from about 3% to 24% of people reported constipation in the trials, depending on the medicine and dose. The table shows the figures from each US prescribing label. Each percentage counts anyone who reported constipation at least once.
| Medicine and trials | Dose | Constipation | Placebo |
|---|---|---|---|
| Wegovy, weight trials (up to 68 weeks) | 2.4 mg weekly | 24% | 11% |
| Wegovy HD, weight trials | 7.2 mg weekly | 20% (19% on 2.4 mg) | 8% |
| Ozempic, type 2 diabetes trials | 0.5 mg / 1 mg weekly | 5% / 3.1% | 1.5% |
| Zepbound, weight trials (up to 72 weeks) | 5 / 10 / 15 mg weekly | 17% / 14% / 11% | 5% |
| Mounjaro, type 2 diabetes trials | 5 / 10 / 15 mg weekly | 6% / 6% / 7% | 1% |
Constipation was common on placebo too, especially in the weight-loss trials, where everyone also followed a reduced-calorie diet. The gap between the columns is the part linked to the medicine. The labels warn that rates from different trials cannot be compared directly, so use the table to set expectations, not to pick a medicine.
Why do GLP-1 medicines cause constipation?
GLP-1 medicines slow how quickly your stomach empties, and all four labels list this effect. Food moves through more slowly, so stool spends longer in the bowel, where water is drawn out and it gets harder. On top of that, eating much less means less food and fiber passing through, and many people drink less because these medicines quiet thirst along with hunger. The 2025 joint advisory from four US nutrition and obesity societies also notes that protein-heavy and fatty meals slow the stomach further.
The labels say most nausea, vomiting and diarrhea happened during the dose step-ups. They do not say the same about constipation, so it is worth building habits that work for the long run rather than waiting it out.
What helps with constipation on a GLP-1?
Fiber, fluids and movement, added together and kept up every day, help most people. NIDDK defines constipation as fewer than three bowel movements a week, or stools that are hard, dry, lumpy or hard to pass.
How much fiber do I need, and how fast should I add it?
Aim for the fiber your body needs, but raise it slowly. NIDDK puts adult needs at about 22 to 34 grams a day, depending on age and sex. The 2025 advisory recommends a gradual increase in foods with both soluble and insoluble fiber, such as prunes or other dried fruits. Adding a lot at once can cause gas and bloating, which can feel worse on a slowed gut. The fiber calculator gives you a daily target.
Good sources that fit small portions:
| Food | Why it helps |
|---|---|
| Prunes, kiwi, pears, berries | Fiber and water; the advisory names prunes and dried fruit |
| Oats, chia, ground flax | Soluble fiber that softens stool; easy to add to yogurt |
| Beans, lentils, chickpeas | Fiber and protein together |
| Vegetables, cooked or raw | Bulk and water; cooked is gentler on a queasy day |
| Whole-grain bread, brown rice | Steady fiber across the day |
If nausea is also an issue, start with soft, cooked or blended options, and build up from a few grams a day. The advisory suggests avoiding high-fiber foods in the first few days of treatment, when nausea is most likely, and then adding fiber back gradually.
How much water should I drink?
More than you might think, because these medicines quiet thirst as well as hunger. NIDDK says to drink plenty of water and other liquids when you eat more fiber or take a fiber supplement. Sip through the day rather than drinking a large glass at meals, which can fill you up fast. The water calculator sets a daily target based on your weight.
Does exercise help with constipation?
Regular physical activity may help, according to NIDDK. A daily walk is a good start, and many people find a short walk after a meal helps things move.
Do bathroom habits matter?
Yes. NIDDK suggests trying to go at the same time each day, often 15 to 45 minutes after breakfast, because eating helps the colon move stool. Go when you feel the urge, give yourself time, and resting your feet on a small footstool can make it easier.
When should I ask about laxatives or stool softeners?
If fiber, fluids and movement have not helped after a few days, talk to a pharmacist or your clinician before trying an over-the-counter product. NIDDK lists several types, including fiber supplements, osmotic laxatives, stool softeners and stimulant laxatives, and says a health care professional can recommend the one that suits you and how long to use it. The 2025 advisory mentions magnesium, fiber supplements, polyethylene glycol and stool softeners as options clinicians use for constipation on GLP-1 therapy. NIDDK advises using stimulant laxatives only when constipation is severe or other treatments have not worked.
Ask before you start, because the right choice depends on your other medicines and health conditions. Tell your prescriber too, so they know how your gut is coping. Follow your prescriber and the label for anything to do with your GLP-1 dose.
When is constipation an emergency?
Constipation is usually uncomfortable but not dangerous. Some signs, though, can mean a blockage or another serious problem. The Wegovy, Ozempic, Zepbound and Mounjaro labels all list ileus, intestinal obstruction and severe constipation including fecal impaction among the problems reported after approval.
Get medical care right away if you have no bowel movement along with severe or constant belly pain, vomiting, a swollen or hard belly, or you cannot pass gas. Also seek care for blood in your stool, fever, or severe stomach pain that will not go away, especially if it spreads to your back.
- Possible obstruction or ileus. Cramping or constant pain, bloating, vomiting and no stool or gas together are the warning pattern.
- Pancreatitis. Severe, ongoing belly pain, sometimes spreading to the back, with or without vomiting. The labels say to stop the medicine if pancreatitis is suspected.
- Gallbladder problems. Pain in the upper right belly, fever, yellow skin or eyes, or clay-colored stools.
- Other signs NIDDK lists for prompt care. Rectal bleeding, constant belly pain, lower back pain, fever, or losing weight without trying.
Call your clinician, too, if constipation does not improve with fiber, fluids and movement, or if it keeps you from eating.
How Morning helps
Morning's food photo scan counts fiber and water toward your daily targets, so you can see on a busy day whether you are short. The side-effect check-ins show whether constipation tends to start after a dose step-up or stretch across the week, and the doctor report puts those notes on one page for your next appointment. Ask Sunny, the chat coach, can suggest high-fiber meals that fit a small appetite, though never dose advice.
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Questions
How long does constipation last on a GLP-1?
It varies. The labels tie most nausea, vomiting and diarrhea to the dose step-ups but do not say the same about constipation, so for some people it continues. Steady fiber, fluids and movement usually keep it manageable; tell your clinician if it does not improve.
Is constipation worse on Ozempic or Mounjaro?
In the diabetes trials in each label, constipation was reported by 3.1% to 5% on Ozempic and 6% to 7% on Mounjaro. The labels warn that different trials cannot be compared directly, so your own experience matters more.
Can I take a laxative on Wegovy or Zepbound?
Ask a pharmacist or your clinician first. There are several types, and they can recommend one that fits your other medicines and health conditions.
Why am I constipated when I eat so little?
Eating less means less bulk passing through, and the medicine slows how fast food moves. Fiber and fluid matter more, not less, when portions are small.
When is constipation on a GLP-1 dangerous?
When it comes with severe or constant belly pain, vomiting, a swollen belly or no gas. Ileus and intestinal obstruction are listed in all four labels' post-marketing reports. Get care right away.
Sources
- Wegovy (semaglutide) US prescribing information, Novo Nordisk
- Ozempic (semaglutide) US prescribing information, Novo Nordisk
- Zepbound (tirzepatide) US prescribing information, Eli Lilly
- Mounjaro (tirzepatide) US prescribing information, Eli Lilly
- DailyMed: Wegovy label
- DailyMed: Zepbound label
- Mozaffarian D et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory. Am J Clin Nutr 2025;122:344-367
- NIDDK: Treatment for Constipation
- NIDDK: Symptoms and Causes of Constipation
Keep reading
Educational information, not medical advice. Talk to your clinician about your treatment.