Constipation on Ozempic, Wegovy or Zepbound: Why It Happens and What Helps

Constipation is one of the most common side effects of semaglutide (Ozempic, Wegovy) and tirzepatide (Zepbound, Mounjaro). Two things add up: the medication slows digestion, and you eat a lot less, so less fiber and often less fluid go in. What usually helps is raising fiber gradually toward the US targets (25 g a day for women and 38 g for men up to age 50), drinking enough, moving and keeping a bathroom routine. If that isn’t enough, a laxative is a question for your prescriber or pharmacist. And if you haven’t had a bowel movement in days and you’re also vomiting or in severe pain, get medical care right away.

I built this guide from the US prescribing information for Wegovy, Zepbound, Ozempic and Mounjaro, the US Dietary Reference Intakes from the National Academies, the constipation pages of the NIDDK (part of the National Institutes of Health), the 2025 British Dietetic Association guideline on constipation and the 2025 joint advisory on nutrition and GLP-1 therapy from four US medical and nutrition societies. The big picture on eating is in my guide to what to eat on GLP-1 medications.

Why GLP-1 medications cause constipation

Digestion slows down. The Wegovy and Zepbound labels both say the drug delays gastric emptying, meaning food moves more slowly from the stomach into the intestine. The 2025 advisory adds that these drugs sometimes also change how the intestine moves and what it secretes, though it links that mainly to diarrhea.

One nuance: the Zepbound label says the delay in gastric emptying is largest after the first dose and diminishes over time, yet in the Wegovy trials constipation lasted much longer than nausea. No label explains why, so it’s safest to assume several factors are at play.

You eat less, and that includes fiber and water. The advisory reports reductions in energy intake of 16% to 39% on these drugs and notes that constipation is common during weight loss. Among the causes of constipation, the NIDDK lists too little fiber, too little fluid, too little physical activity and changes in how much and what you eat.

Protein and fat slow things down too. The advisory warns that very high-protein or high-fat foods can slow stomach emptying further and worsen constipation. That’s no reason to drop protein, which helps preserve muscle: it’s a balance I explain in the main guide and in protein and muscle on GLP-1 medications.

How often it happens, according to the labels

Medication	US label: constipation, drug vs. placebo	What else the labels say
Wegovy (semaglutide 2.4 mg, weight management)	24% vs. 11% (three trials, up to 68 weeks)	EU prescribing information: mild to moderate and longer-lasting, with a median of 47 days, versus 8 days for nausea
Zepbound (tirzepatide 5, 10 and 15 mg, weight management)	17%, 14% and 11% vs. 5% (two trials, up to 72 weeks)	No duration reported
Ozempic (semaglutide 0.5 and 1 mg, type 2 diabetes)	5.0% and 3.1% vs. 1.5%	EU prescribing information: in the SUSTAIN 9 trial, added to an SGLT2 inhibitor (another diabetes drug), 6.7% on semaglutide 1 mg versus no cases on placebo, and it didn’t decrease over time
Mounjaro (tirzepatide 5, 10 and 15 mg, type 2 diabetes)	6%, 6% and 7% vs. 1%; 13% in a cardiovascular outcomes trial in adults with type 2 diabetes and heart disease (no placebo figure given)	No duration reported

Sources: US labels, section 6.1 (Wegovy Table 3, Zepbound Table 1, Ozempic Table 1, Mounjaro Table 1); EU prescribing information for Wegovy and for Ozempic for the details the US labels don’t give. The 2025 advisory cites the same Zepbound figure for the 15 mg dose: 11% versus 5% on placebo.

The Wegovy label says gastrointestinal reactions were most frequently reported during dose escalation. As with any side-effect table, these figures come from different trials and don’t compare the drugs with each other.

How much fiber you need, and which kind

The National Academies, the body that sets the US Dietary Reference Intakes, recommend 25 g of total fiber a day for women and 38 g for men up to age 50, and 21 g and 30 g after 50. One caveat: those US figures are based on heart-disease risk, not on bowel function. They’re still the standard reference, and small portions make them hard to reach.

MedlinePlus, from the US National Library of Medicine, describes two types:

• Soluble: attracts water and turns to gel during digestion. It’s in oat bran, barley, nuts, seeds, beans, lentils, peas and some fruits and vegetables.
• Insoluble: adds bulk to stool and appears to help food pass more quickly through the gut. It’s in wheat bran, vegetables and whole grains.

A mix of beans, fruit, vegetables and whole grains covers both. That said, the British guideline found no trials proving that a high-fiber diet helps chronic constipation: almost all the evidence is for fiber supplements.

15 high-fiber foods per typical serving

Picked from our food database and ranked by the fiber in a typical serving. I include protein because, with a small appetite, it helps if every plate counts for both. Beans, lentils and grains are cooked; vegetables are raw except the peas. US cup measures are approximate.

Food	Serving	Fiber	Protein	Note
Black beans	150 g (a scant cup)	13.1 g	13.3 g	Gas
Lentils	150 g (about ¾ cup)	11.9 g	13.5 g	Gas
Chickpeas (garbanzo beans)	150 g (a scant cup)	11.4 g	13.3 g	Gas
White beans	150 g (a scant cup)	9.5 g	14.6 g	Gas
Whole-wheat pasta	150 g (about 1 cup)	5.9 g	9.0 g
Green peas	100 g (about ⅔ cup)	5.5 g	5.4 g	Gas
Pear	170 g (about one medium)	5.3 g	0.6 g
Avocado	70 g (2.5 oz)	4.7 g	1.4 g
Orange	180 g (one large)	4.3 g	1.7 g
Apple with skin	180 g (about one medium)	4.3 g	0.5 g
Green beans	150 g (about 1½ cups)	4.1 g	2.7 g
Broccoli	150 g (about 1½ cups, chopped)	3.9 g	4.2 g	Gas
Oatmeal, cooked with water	200 g (a scant cup)	3.4 g	5.1 g
Almonds	25 g (0.9 oz, about 20)	3.1 g	5.3 g
Kiwifruit, green	100 g (3.5 oz, one or two fruits)	3.0 g	1.1 g

Composition data: USDA FoodData Central, as used in the food pages (in Spanish). “Gas” flags the beans and broccoli, which the NIDDK notes cause more gas in some people. Servings are a guide, not a recommendation. More options in high-fiber foods (in Spanish).

A 7-day plan to add fiber without the bloating

The NIDDK recommends adding fiber a little at a time so your body can get used to it, and high-fiber foods cause more gas in some people. This plan adds one food to what you already eat, with fluids spread through the day.

Day	What you add	Fiber added	Running total
1	Kiwifruit (100 g, 3.5 oz)	3.0 g	3.0 g
2	A thick slice of whole-wheat bread (40 g, 1.4 oz)	2.4 g	5.4 g
3	Nothing new: see how it sits	0 g	5.4 g
4	Oatmeal cooked with water (200 g, a scant cup)	3.4 g	8.8 g
5	Half a serving of cooked lentils (75 g, about ⅓ cup)	5.9 g	14.7 g
6	An apple with skin (180 g)	4.3 g	19.0 g
7	A handful of almonds (25 g, about 20)	3.1 g	22.1 g

If you notice more gas, stay at the previous step for two or three days. If you can’t manage all of it, keep what you tolerate best. If you’re in the first days of treatment and have nausea, the 2025 advisory suggests holding off on very high-fiber foods for now; I explain why in nausea on GLP-1 medications and what to eat. If you have a digestive condition or have been told to limit fiber, check with your doctor first.

Water: how much, and why it matters

The National Academies found that adequately hydrated women take in about 2.7 liters (91 oz) of total water a day and men about 3.7 liters (125 oz), counting all drinks and foods. About 20% usually comes from food, so when you eat less, you also get less water from your plate.

Fluids help fiber do its job, according to the NIDDK. The British guideline adds a nuance: drinking more on its own hasn’t been shown to relieve chronic constipation. The only trial that tested it combined 2 liters (about 68 oz) of water a day with a 25 g fiber diet, and bowel movements became more frequent. Fiber and water work together.

The US labels also report postmarketing cases of acute kidney injury, mostly in people whose nausea, vomiting or diarrhea led to dehydration. If you have kidney or heart disease and have been told to limit fluids, follow what your doctor has told you.

Movement and a bathroom routine

The NIDDK says regular physical activity may help relieve constipation. It doesn’t specify a type or amount; if you have a health limitation, ask your doctor what suits you.

For the routine, it describes trying to go at the same time each day, for example 15 to 45 minutes after breakfast, because eating helps your colon move stool. Also: give yourself enough time, go as soon as you feel the urge, and rest your feet on a low footstool.

Kiwifruit, prunes and psyllium: what the evidence says

The British Dietetic Association guideline reviewed trials in adults with chronic constipation, not in people taking GLP-1 medications:

• Psyllium (ispaghula husk): this is the fiber supplement the guideline recommends. It increased the number of bowel movements and softened stool. The evidence is low quality, but the recommendation is strong. If you’re interested, bring it up with your prescriber or pharmacist.
• Kiwifruit: compared with psyllium it worked about as well, with roughly 0.36 more bowel movements a week, a small difference. The guideline mentions 2 or 3 kiwifruit a day for at least 4 weeks and considers them a good option if psyllium gives you bloating, pain or gas.
• Prunes: only two trials, with fewer than 100 people, and no difference versus psyllium. The guideline doesn’t conclude they work as well. The 2025 advisory does list them among foods that may help.

Laxatives: a question for your prescriber or pharmacist

The 2025 advisory recommends managing constipation proactively and acknowledges that fiber and fluids often aren’t enough. There are several kinds of laxatives, including fiber supplements, osmotic laxatives, stool softeners and stimulants, and the NIDDK says it’s your health care professional who picks the type and how long to use it, usually for a short time. When you ask, mention that you take semaglutide or tirzepatide and list your other medications.

Warning signs: when not to wait

The list combines the NIDDK with the labels. All four US labels list ileus, intestinal obstruction and severe constipation including fecal impaction among reports received after the drugs went on the market, where the frequency can’t be estimated. The Medication Guides add a general warning: stomach problems, sometimes severe, have been reported; tell your healthcare provider if you have stomach problems that are severe or will not go away.

Acute pancreatitis (inflammation of the pancreas) is rare: in the Wegovy weight-management trials, the label reports 4 adjudication-confirmed cases on Wegovy (0.2 per 100 patient-years) versus 1 on placebo. The Wegovy and Zepbound Medication Guides describe the symptom to act on: severe pain in your stomach area (abdomen) that will not go away, with or without nausea or vomiting, sometimes felt from your abdomen through to your back, means calling your healthcare provider right away.

Also see your doctor, without the rush, if these measures don’t help or if you have a family history of colon or rectal cancer. And if you alternate between constipation and diarrhea, mention it: the 2025 advisory warns that long-lasting constipation can trigger reactive diarrhea.

Frequently asked questions

How long does constipation last on Ozempic, Wegovy or Zepbound?

In the Wegovy trials, the median was 47 days, according to the EU prescribing information. None of the four US labels reports how long it lasts.

How many days without a bowel movement is too many?

The NIDDK describes constipation as fewer than three bowel movements a week, hard stools or trouble passing them, and reminds you that everyone has their own pattern. What comes with it matters more: vomiting, severe pain, bloating or not passing gas are reasons to get care right away.

Can I take a laxative on semaglutide or tirzepatide?

That’s a decision for your prescriber or pharmacist, who will pick the type and how long to use it based on your situation.

Do kiwifruit and prunes really work?

Kiwifruit has favorable trials in chronic constipation; prunes have few, of lower quality. None were done in people taking GLP-1 medications.

Do I have to stop treatment if I’m constipated?

That’s not a decision to make on your own: talk to your prescriber. In the Wegovy trials, constipation was mild to moderate. If you also have nausea, my guide to nausea on GLP-1 medications and what to eat may help.