Side effects

Constipation on GLP-1 medications

Pending medical review

By Joshua Nichvolodoff · Fact-checked against sources November 2, 2026 · Next review due May 1, 2027

Clinical review: not yet reviewed by a clinician. How review works · Editorial policy

Constipation is less talked about than nausea, but in trials it tended to last longer. Here is how often it was reported with semaglutide and tirzepatide, what a 2025 nutrition advisory suggests, and the warning signs the labels say to act on.

How often it was reported

People reporting constipation in the trials behind each US label[1][3][4][5]
ItemOn the medicineOn placebo
Wegovy 2.4 mg (weight management)24%11%
Zepbound 5 / 10 / 15 mg (weight management)17% / 14% / 11%5%
Ozempic 0.5 mg / 1 mg (type 2 diabetes)5% / 3.1%1.5%
Mounjaro 5–15 mg (type 2 diabetes)6–7%1%
Different trials, populations and doses — compare within a row, not across rows.

How long it lasted in trials

In a pooled analysis of the STEP 1–3 trials, constipation was reported by 24.2% of people on semaglutide 2.4 mg versus 11.1% on placebo, and lasted longer than other stomach-related side effects — a median of 47 days, versus 35 days on placebo[2]. Canada's Wegovy monograph also describes these events as mild to moderate but longer-lasting[6]. Across the SURMOUNT tirzepatide trials, most stomach-related side effects were not serious[7].

What may help

The 2025 joint nutrition advisory encourages adequate fluids and fibre from foods, with fibre increased gradually, and notes that additional strategies are often needed[8]. Reference fibre intakes for adults are 25–38 g a day depending on age and sex[9]. Ask your pharmacist or prescriber before starting a laxative or fibre supplement.

Warning signs

Since these medicines were approved, reports have included ileus (the bowel stopping moving), intestinal obstruction, and severe constipation including fecal impaction[1][3]. In one US insurance-claims study of people using GLP-1 medicines for weight loss, their use was linked to a higher risk of bowel obstruction than another weight-loss medicine, though the absolute numbers were small[10]. The labels advise contacting a healthcare provider about severe or persistent stomach symptoms[1].

General information from product labels and published studies — not medical advice.

Sources

  1. WEGOVY (semaglutide) injection and tablets — prescribing information and Medication Guide (revised 06/2026). U.S. Food and Drug Administration, June 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/218316s007lbl.pdf. Accessed November 2, 2026. Back to the text
  2. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss. Diabetes, Obesity and Metabolism, January 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9293236/ · DOI 10.1111/dom.14551 · PMID 34514682. Accessed November 2, 2026. Back to the text
  3. ZEPBOUND (tirzepatide) injection — prescribing information and Medication Guide (revised 04/2026). U.S. Food and Drug Administration, April 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/217806Orig1s050lbl.pdf. Accessed November 2, 2026. Back to the text
  4. OZEMPIC (semaglutide) injection — prescribing information (revised 05/2026). U.S. Food and Drug Administration, May 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/209637s038lbl.pdf. Accessed November 2, 2026. Back to the text
  5. MOUNJARO (tirzepatide) injection — prescribing information (revised 08/2026). U.S. Food and Drug Administration, August 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/215866s044s045lbl.pdf. Accessed November 2, 2026. Back to the text
  6. WEGOVY (semaglutide injection) product monograph (authorized December 10, 2025). Health Canada Drug Product Database / Novo Nordisk Canada, December 10, 2025. https://pdf.hres.ca/dpd_pm/00082777.PDF. Accessed November 2, 2026. Back to the text
  7. Gastrointestinal tolerability and weight reduction associated with tirzepatide in adults with obesity or overweight with and without type 2 diabetes in the SURMOUNT-1 to -4 trials. Diabetes, Obesity and Metabolism, April 2025. https://pubmed.ncbi.nlm.nih.gov/39789843/ · DOI 10.1111/dom.16176 · PMID 39789843. Accessed November 2, 2026. Back to the text
  8. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. American Journal of Lifestyle Medicine, May 30, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12125019/ · DOI 10.1177/15598276251344827 · PMID 40452753. Accessed November 2, 2026. Back to the text
  9. Dietary reference intakes tables: reference values for macronutrients. Health Canada, November 19, 2025. https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables/reference-values-macronutrients-dietary-reference-intakes-tables-2005.html. Accessed November 2, 2026. Back to the text
  10. Risk of gastrointestinal adverse events associated with glucagon-like peptide-1 receptor agonists for weight loss. JAMA, November 14, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC10557026/ · DOI 10.1001/jama.2023.19574 · PMID 37796527. Accessed November 2, 2026. Back to the text

Figures marked “as reported” are historical: they show what the source said on that date, not today's price or rule.

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Substantive corrections are also logged at corrections.

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