GLP-1 Constipation: Why It Happens and What Can Help
In this guide
This article is for information only and is not medical advice. Talk to your prescriber or a qualified professional.
Constipation is one of the most commonly listed side effects of GLP-1 medicines. These drugs slow how fast food leaves your stomach, and eating less food and fewer fluids can add to the problem. The general habits that help most people are enough fluids, fiber from food added gradually, and regular movement. Severe belly pain, blood in your stool, or constipation that does not respond to self-care is a reason to call your prescriber. This guide does not name laxatives or doses, because the right choice depends on you.
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Part of the GLP-1 side effects timeline, where you can see how all the common symptoms fit together.
Why constipation shows up on GLP-1 medicines
GLP-1 medicines slow gastric emptying, which is part of how they make you feel full. A slower gut plus smaller meals, less fiber and less fluid can mean fewer or harder bowel movements. Nothing here tells you what is happening in your own body. Only your prescriber can do that.
How common is it? The Wegovy prescribing information reports constipation in 24% of adults on the 2.4 mg injection versus 11% on placebo, in three placebo-controlled trials of up to 68 weeks. The Zepbound label reports 17% at 5 mg, 14% at 10 mg and 11% at 15 mg versus 5% on placebo in its weight-reduction trials. Different trials, different designs, so treat these as a sense of scale and not a comparison.
How long can it last?
Unlike nausea, constipation does not always fade quickly. A 2022 expert review of stomach side effects with GLP-1 medicines reports that constipation lasted a median of 47 days in people with obesity treated with them. That is a general figure from the literature, not a promise for you. If it drags on, tell your prescriber instead of waiting it out.
Habits that are commonly suggested
Fluids
NIDDK, part of the US National Institutes of Health, says drinking water and other liquids helps fiber work better and that staying hydrated can help you avoid constipation. NIDDK suggests asking a health care professional how much to drink based on your size, health and activity level. For ideas, see GLP-1 drinks and hydration.
Fiber from food, added slowly
NIDDK says adults should get 22 to 34 grams of fiber a day depending on age and sex, and to add fiber a little at a time so your body can adjust. A big jump in fiber can backfire if you are also eating small portions. The 2025 joint advisory on nutrition for GLP-1 therapy suggests fiber from foods with plenty of water in them, such as certain fruits and vegetables, and mentions prunes and dried fruit as options to add gradually. It also notes that very high-protein or high-fat meals can slow the stomach further, so some people temporarily ease off those if they make things worse. More in GLP-1 fiber and how to hit your protein target.
Move your body
NIDDK says regular physical activity may help relieve constipation. A walk after a meal counts.
Do not ignore the urge
NIDDK also suggests using the bathroom as soon as you feel the need to go and trying to build a regular daily routine.
About laxatives and supplements
People often ask which laxative or supplement to use. This page does not recommend any, and it does not give doses. The joint advisory describes several categories that clinicians may suggest, but the right product depends on your health, your other medicines and how severe the problem is. NIDDK advises checking with a health care professional before using laxatives or fiber supplements, and not changing or stopping any medicine or supplement without talking to a professional. Ask your pharmacist or prescriber. A pharmacist can answer this in a few minutes.
One more link: the advisory points out that long-lasting constipation can lead to reactive diarrhea, so a loose day does not always mean the constipation is gone. See GLP-1 diarrhea for that side.
When to call your prescriber or get care
Constipation alone is common, but these are signs to get checked. NIDDK advises seeing a doctor if constipation comes with bleeding from the rectum, blood in the stool, constant belly pain, or weight loss you did not intend, or if it does not go away with self-care. In addition, from the GLP-1 labels and medication guide:
- Severe stomach pain that will not go away, with or without vomiting, possibly spreading to the back. The labels warn about pancreatitis.
- Severe stomach or intestinal problems. MedlinePlus lists these among reasons to get medical help, and the Wegovy and Zepbound labels say these medicines are not recommended for people with severe gastroparesis.
- Signs of dehydration or kidney trouble, such as dark urine, urinating less than usual, dizziness, or swelling of the legs, ankles or feet (NIDDK and MedlinePlus).
This list is not complete. When something feels wrong, call your prescriber, a pharmacist or local emergency services.
Frequently asked questions
Does semaglutide cause constipation?
Constipation is listed as a common side effect of semaglutide. MedlinePlus lists it among the common side effects of semaglutide injection, and the Wegovy label reports it in 24% of people on the 2.4 mg dose versus 11% on placebo in its trials.
Does tirzepatide cause constipation too?
Yes. The Zepbound label lists constipation among its most common adverse reactions, reported at 17%, 14% and 11% for the 5 mg, 10 mg and 15 mg doses versus 5% on placebo.
How long does GLP-1 constipation last?
It varies. One expert review reports a median of 47 days in people with obesity on GLP-1 medicines, but some people see it fade faster and others longer. Tell your prescriber if it does not improve.
Can I take a laxative?
Ask your pharmacist or prescriber. They can pick something that fits your health and other medicines, and they can tell you how long it is reasonable to use it.
Keep a simple record
Writing down your bowel pattern, your shot date, how much you drank and how much fiber you ate gives your prescriber something concrete to work with. The Dosinha free side-effect check-in, shot log and water tracking help you keep that record and notice patterns to share. They do not treat constipation. Look around Dosinha. Related: feeling off after a dose and GLP-1 nausea.
Sources
- Novo Nordisk. Wegovy prescribing information, DailyMed. Current label.
- Eli Lilly. Zepbound prescribing information. Current label.
- NIDDK. Constipation: eating, diet and nutrition, symptoms and causes and treatment. US National Institutes of Health.
- Mozaffarian D et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. 2025.
- Gorgojo-Martinez JJ et al. Clinical recommendations to manage gastrointestinal adverse events in patients treated with GLP-1 receptor agonists. J Clin Med, 2022.
- NIDDK. Diarrhea: symptoms and causes (dehydration signs).
- MedlinePlus. Semaglutide injection. US National Library of Medicine.
This article is for information only and is not medical advice. Talk to your prescriber or a qualified professional.