Tirzepatide Constipation: What to Know and Ask Your Prescriber

Constipation is a reported side effect of tirzepatide, the ingredient in Zepbound and Mounjaro. How often it was reported depends on the product’s study population and treatment context. Those figures can help you understand the evidence, but they cannot tell you why your own bowel habits have changed. 1, 2

If you are having symptoms, the useful next step is to describe what changed to the clinician managing your prescription. Some symptoms need assessment right away; you do not need to wait for a routine follow-up to report them.

What counts as constipation?

Constipation can involve fewer than three bowel movements a week, hard or lumpy stools, painful or difficult bowel movements, or a feeling that stool has not fully passed. Frequency is only one part of the picture. 3

Explain how your current pattern differs from your usual one. Saying “I am still going, but passing stool hurts and it feels incomplete” gives your prescriber different information from “I have not had a bowel movement.”

Which symptoms need prompt medical attention?

Seek medical assessment right away if constipation comes with constant abdominal pain, inability to pass gas, vomiting, fever, rectal bleeding or blood in the stool. NIDDK identifies these as reasons to see a doctor right away. They are not symptoms to dismiss as an expected medication adjustment. 3

Persistent or severe abdominal pain, sometimes extending to the back, can be a warning sign of pancreatitis. The Zepbound and Mounjaro prescribing information directs patients to stop the medicine promptly and contact their clinician if pancreatitis is suspected. Follow the urgent instructions supplied with your own prescription. 1, 2

Also contact your prescriber for severe or persistent digestive symptoms, including symptoms that make eating or drinking difficult. Both labels warn about severe gastrointestinal reactions and dehydration-related kidney injury. This is a focused symptom guide, not a complete list of medication risks. 1, 2

How common was constipation in tirzepatide studies?

The current US labels report several different study settings:

Product and study population	Reported constipation	Context
Zepbound: pooled weight-reduction Studies 1 and 2 in adults with obesity or overweight, with or without type 2 diabetes	17%, 14% and 11% with 5, 10 and 15 mg; 5% with placebo	Treatment up to 72 weeks plus a four-week off-drug follow-up; the adverse-reaction category includes hard stools. 1
Mounjaro: pooled placebo-controlled trials in adults with type 2 diabetes	6%, 6% and 7% with 5, 10 and 15 mg; 1% with placebo	Percentages count patients reporting at least one occurrence. 2
Mounjaro: cardiovascular-outcomes trial in adults with type 2 diabetes and established cardiovascular disease	13% among Mounjaro-treated participants	A separate trial population; this figure is not the pooled placebo-controlled estimate above. 2

The original 72-week SURMOUNT-1 trial, which excluded diabetes, reported constipation in 16.8%, 17.1% and 11.7% of the 5, 10 and 15 mg groups, compared with 5.8% with placebo. That single trial is different from the two-study pool in Zepbound’s label. 4

These are reports within particular studies, not a comparison proving that one brand is safer or a prediction for an individual. The dose groups also do not provide instructions for changing a prescription to manage constipation.

The figures concern studied branded products. Compounded tirzepatide is distinct: compounded drugs are not FDA approved or reviewed by FDA for safety, effectiveness and quality before marketing. Do not assume a branded trial establishes the constipation rate for an unspecified compounded preparation. 5

Why might bowel habits change?

Tirzepatide can slow stomach emptying. A small, short phase 1 study measured that effect using acetaminophen absorption; it diminished with repeated dosing, although some delay remained in participants with type 2 diabetes receiving escalating doses. The study did not establish the cause or duration of constipation in an individual. 6

Stomach emptying and passing stool are different processes. A finding about the stomach does not explain every bowel symptom. NIDDK notes that constipation can have several contributors, including changes in eating, insufficient fiber or liquids, activity changes, other medicines and underlying health conditions. More than one cause can be present. 3

That is why a medication review should include what else changed around the same time, rather than assuming tirzepatide is the only possible explanation.

How long does tirzepatide constipation last?

The evidence above does not supply a reliable countdown for when an individual’s constipation will resolve. A percentage reported during a long trial does not tell you how long each episode lasted. Likewise, a diminishing effect on stomach emptying does not establish a constipation recovery date. 1, 2, 6

Ask your prescriber when to check back and which changes should prompt earlier contact. Use symptoms and the agreed care plan, rather than an online promise that it will pass within a set number of days.

What should you tell your prescriber?

NIDDK’s diagnostic guidance emphasizes symptom history, bowel patterns, eating and activity habits, medicines and supplements. A brief written record can help you describe the problem. 7

Have these details ready:

• Your exact medication name and the directions on your prescription.
• When constipation began, your usual bowel pattern and your most recent bowel movement.
• Whether stools are hard, painful to pass or feel incomplete.
• Any abdominal pain, vomiting, bleeding, trouble passing gas or difficulty eating and drinking.
• Recent changes in food, fluids, activity, medicines or supplements.
• Anything you have already tried, including over-the-counter products.

Do not delay urgent care to finish a symptom diary. Its purpose is to make a conversation clearer, not to decide whether a warning sign matters.

Which treatment questions are worth asking?

Ask your prescriber to make the next step specific:

• Could another medicine, supplement or health condition be contributing?
• Which food, fluid or activity changes are suitable for me?
• Would an over-the-counter constipation treatment be appropriate, and which type and duration would you recommend?
• Does my symptom pattern need an examination or further assessment?
• What should I do if symptoms persist, and whom should I contact between visits?
• How should I handle my prescription while you assess the problem?

NIDDK describes dietary changes, activity and clinician-selected medicines among constipation treatments. It also advises discussing suspected medication causes with a health professional rather than changing or stopping medicines independently. A general article cannot choose a laxative regimen or medication adjustment for you; urgent medication-safety instructions still apply. 8

Contact the clinician managing your prescription with your symptoms and medication details, and ask for a plan you can follow. Confirm when to reassess it and what would require faster attention.

Sources

1. Zepbound US prescribing information, Eli Lilly and Company. Revised August 2026; sections 5, 6.1, 12.2 and 17. Checked October 23, 2026.
2. Mounjaro US prescribing information, Eli Lilly and Company. Revised August 2026; sections 5, 6.1, 14.6 and 17. Checked October 23, 2026.
3. Symptoms & Causes of Constipation, NIDDK. Last reviewed May 2018; checked October 23, 2026.
4. Tirzepatide Once Weekly for the Treatment of Obesity, Jastreboff AM et al., New England Journal of Medicine, 2022;387:205–216. Original SURMOUNT-1 report, Table 4; checked October 23, 2026.
5. FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. Checked October 23, 2026.
6. The novel dual GIP and GLP-1 receptor agonist tirzepatide transiently delays gastric emptying similarly to selective long-acting GLP-1 receptor agonists, Urva S et al., Diabetes, Obesity and Metabolism, 2020;22:1886–1891. Checked October 23, 2026.
7. Diagnosis of Constipation, NIDDK. Last reviewed May 2018; checked October 23, 2026.
8. Treatment for Constipation, NIDDK. Last reviewed May 2018; checked October 23, 2026.