Is diarrhoea a common side effect of Mounjaro?

Diarrhoea is among the side effects most often reported with Mounjaro. It tends to be most noticeable when starting treatment or after a dose increase, and often improves with time. The Patient Information Leaflet gives the official frequency.

Should I stop Mounjaro because of diarrhoea?

Do not stop or change your treatment without speaking to your prescriber, unless you have symptoms that need urgent care, such as severe persistent stomach pain. Your prescriber may suggest staying on your current dose for longer, adjusting your dose or other measures. You can also report suspected side effects to the MHRA Yellow Card scheme.

Mounjaro and diarrhoea: causes, tips and when to get help

Diarrhoea on Mounjaro (tirzepatide): why it happens, self-care measures and the warning signs that need medical help.

Get urgent medical help if:

you have signs of severe dehydration, such as confusion, fainting or passing very little urine

Call 999 or go to A&E in an emergency. For urgent advice, call NHS 111.

About diarrhoea on Mounjaro

Loose or more frequent stools are commonly reported with GLP-1 medicines and usually improve as the body adjusts. Persistent diarrhoea can cause dehydration.

Diarrhoea is listed among the commonly reported side effects of Mounjaro in our reference data.

Things that may help

Drink plenty of fluids to replace what you lose
Eat smaller meals and limit very fatty or spicy foods
Ask a pharmacist about oral rehydration sachets

A pharmacist can advise on suitable over-the-counter options.

Speak to your prescriber if

diarrhoea lasts more than a few days or is severe
you notice blood in your stools
you take oral contraception or other medicines whose absorption could be affected

Report suspected side effects through the MHRA Yellow Card scheme. Reports help the MHRA monitor the safety of medicines.

Frequently asked questions

Related guides

Other Mounjaro side effects

All Mounjaro side effects