Independent UK medicine guidance
Mounjaro and gallstones: symptoms and warning signs
Gallstones are listed as a common Mounjaro side effect when tirzepatide is used for weight management. Inflammation or infection of the gallbladder, known as cholecystitis, is listed as uncommon in weight management. This guide explains what gallbladder pain feels like and when it becomes an emergency.
Key facts
- Gallstones are a common side effect of Mounjaro in weight management: up to 1 in 10 people (UK leaflet, revised August 2026).
- In adults treated for type 2 diabetes they are uncommon, up to 1 in 100. In the type 2 diabetes cardiovascular disease study they were common.
- Rapid weight loss itself raises gallstone risk, which is part of why the weight-management figure is higher.
- Cholecystitis, inflammation of the gallbladder, is a separate and less frequent complication: uncommon in weight management.
- Severe pain under the right ribs with fever or yellowing of the skin or eyes needs urgent care: call 999 or go to A&E.
How common is it?
The events were positively correlated with weight reduction. This means the risk may be connected partly to losing weight, particularly rapid weight loss, rather than being a simple direct effect of the medicine.
Those bands describe weight management. The UK patient leaflet revised in August 2026 reports different figures for other patient groups: gallstones were common in a type 2 diabetes cardiovascular disease study but uncommon in adults treated for type 2 diabetes alone, and cholecystitis was common in that cardiovascular study while remaining uncommon in weight management. If you are taking Mounjaro for weight loss, the weight-management bands above are the ones that apply to you.
What do gallstones feel like?
Gallstones often cause no symptoms. When a stone blocks a bile duct, symptoms can include:
- Constant or severe pain in the upper abdomen
- Pain under the ribs on the right
- Pain spreading to the back or right shoulder
- Nausea or vomiting
- Pain lasting longer than 30 minutes
This is different from the brief discomfort, wind or mild stomach upset commonly experienced during treatment.
When is it an emergency?
Contact NHS 111 urgently if abdominal pain lasts longer than 30 minutes.
Call 999 or attend A&E for sudden severe abdominal pain, particularly if it is accompanied by repeated vomiting, pain spreading into the back, a high temperature or shivering, yellowing of the skin or whites of the eyes, or confusion, collapse or severe weakness.
Severe persistent pain spreading to the back can also indicate pancreatitis, another serious condition requiring immediate assessment.
Read the full guide to pancreatitis warning signsCan gallstones be prevented?
There is no guaranteed prevention method. Avoiding crash dieting and excessively rapid weight loss may reduce risk. A balanced diet, sustainable rate of weight loss and appropriate hydration are sensible foundations.
Tell your prescriber if you have previously had gallstones, gallbladder inflammation or pancreatitis. New abdominal pain should be assessed rather than dismissed as an ordinary Mounjaro side effect.
Evidence update, September 2026: SURPASS-CVOT gallstone figure in the revised SmPC
On 8 September 2026 the electronic medicines compendium (eMC) published a revised Mounjaro Summary of Product Characteristics with a text revision date of 29 August 2026. It adds safety results from SURPASS-CVOT, a large trial that compared tirzepatide with dulaglutide, another injectable diabetes medicine, in adults with type 2 diabetes and established cardiovascular disease. The study-specific figure relevant to this page is:
- Gallstones (cholelithiasis): 2.4% of participants taking tirzepatide
- For comparison, the pooled SURMOUNT weight-management studies quoted above reported acute gallbladder disease in 2% on tirzepatide and 1.6% on placebo, a different endpoint in a different population, so the two figures are not directly comparable
The figure substantiates the common category recorded for that study population in the UK patient leaflet revised in August 2026. It does not add a new side effect and it does not change the emergency advice above.
Source: Mounjaro Summary of Product Characteristics (eMC), text revised 29 August 2026, section 4.8
Common questions
Does Mounjaro cause gallstones?
Gallstones are listed as a common side effect of Mounjaro when used for weight management. In pooled SURMOUNT studies, acute gallbladder disease was reported in 2% of participants taking tirzepatide and 1.6% taking placebo, and the events were positively correlated with the amount of weight reduced. The risk may therefore be connected partly to weight loss itself rather than being a simple direct effect of the medicine.
Is the gallstone risk the same for diabetes and weight loss?
No. The UK patient leaflet reports frequencies by the population studied. Gallstones are common in weight management and were also common in a type 2 diabetes cardiovascular disease study, but uncommon in adults treated for type 2 diabetes alone. Cholecystitis runs the other way round: common in that cardiovascular study, uncommon in weight management. Rapid weight loss is itself a known risk factor for gallstones, which is the most likely reason the weight-management figure sits higher.
What does gallbladder pain feel like?
When a stone blocks a bile duct, pain is often constant or severe in the upper abdomen, may sit under the ribs on the right, can spread to the back or right shoulder, may come with nausea or vomiting, and can last longer than 30 minutes. That is different from brief wind or mild stomach upset.
When should I get urgent help for abdominal pain?
Contact NHS 111 urgently if abdominal pain lasts longer than 30 minutes. Call 999 or attend A&E for sudden severe abdominal pain, especially with repeated vomiting, pain spreading into the back, a high temperature or shivering, yellowing of the skin or eyes, or confusion, collapse or severe weakness.
Related guides
Sources: Mounjaro Summary of Product Characteristics (eMC) • NHS gallstones guidance
Explore other side effects
Tap a point on the body to jump to that symptom, or choose from the full list below. The pink marker shows where you are now.
© 2026 Medstack Ltd. Written and published by Monj (monj.co.uk). You are welcome to link to this page or quote a short extract with a credit and a link. Republishing the text, page structure, safety-routing design or price data, in whole or in part, including to train or ground an automated system, is not permitted without written permission. See our independence statement and editorial and review policy.
Sources referenced on this page
Linked from the text above:
- Mounjaro Summary of Product Characteristics (eMC), text revised 29 August 2026, section 4.8 www.medicines.org.uk
- NHS gallstones guidance www.nhs.uk
Standing primary references for every Monj page:
- Mounjaro (tirzepatide) Summary of Product Characteristics and Patient Information Leaflet, electronic medicines compendium
- MHRA Drug Safety Update: GLP-1 receptor agonists
- NICE TA1026: tirzepatide for managing overweight and obesity
- General Pharmaceutical Council register of pharmacies
- MHRA Yellow Card scheme
