Did Mounjaro Cause My Gallstones? GLP-1, Rapid Weight Loss and the Real Risk (UK Guide)
Author context: I lost 6 stone using Mounjaro (GLP-1) over 12 months and later required emergency NHS gallbladder surgery in February 2026. This article explains what the science says — calmly and responsibly.
Short answer: Mounjaro does not directly create gallstones. However, rapid weight loss — which often occurs during GLP-1 treatment — is a recognised risk factor for gallstone formation.
If you’re asking this question, it’s usually because something scary has happened. I asked it too.
You can read my full emergency surgery story here →
Start here: If you’re dealing with gallbladder symptoms (or recovery after removal) and want the full UK guide — symptoms, red flags, A&E triggers, surgery, recovery, diet and GLP-1 context — use the mega hub below.
GLP-1, Gallstones & Gallbladder Removal (UK): Mega FAQ Guide →
Does Mounjaro cause gallstones?
Mounjaro does not directly form gallstones. Gallstones develop when bile becomes overly concentrated with cholesterol and the gallbladder does not empty effectively. Rapid fat loss increases this risk.
- Weight loss increases cholesterol secretion into bile
- Gallbladder emptying may slow during caloric restriction
- Cholesterol crystals can accumulate and solidify
This mechanism is not unique to GLP-1 medications. It is also observed after bariatric surgery and crash dieting.
Why rapid weight loss increases gallstone risk
When body fat is broken down quickly, stored cholesterol is mobilised. The liver processes this and secretes more cholesterol into bile.
At the same time:
- The gallbladder may contract less frequently
- Bile may remain in the gallbladder longer
- Crystallisation becomes more likely
In simple terms: the faster weight drops, the more bile chemistry can shift toward stone formation in susceptible individuals.
Table: What actually drives gallstone risk?
| Factor | Level of Influence | Why It Matters |
|---|---|---|
| Rapid weight loss | High | Changes bile cholesterol concentration |
| GLP-1 medication itself | Indirect | Accelerates fat loss in some individuals |
| Crash dieting | High | Extreme calorie deficit shifts bile chemistry |
| Genetic predisposition | Variable | Family history affects bile composition |
Are gallstones listed as a GLP-1 side effect?
Yes — gallbladder-related events appear in medication documentation. However, this reflects association with weight loss rather than a direct stone-forming effect.
Important nuance:
- Most GLP-1 users do not develop gallstones
- Risk increases with faster weight loss
- Individual biology matters
My case: context matters
I lost 6 stone over 12 months. Then I experienced:
- Upper right abdominal pain
- Back pain under the shoulder blade
- Symptoms that felt like trapped wind at first
Blood tests showed inflammation. Imaging confirmed obstruction. Surgery followed.
That experience forced me to separate emotion from physiology.
Who is most at risk?
- People losing weight rapidly (especially more than 1–2kg per week)
- Individuals with previous gallbladder sludge
- Those with metabolic syndrome history
- People combining GLP-1 with extreme calorie restriction
Should you stop Mounjaro if gallstones develop?
Do not stop prescribed medication without medical advice.
Management depends on:
- Severity of symptoms
- Presence of infection
- Whether surgery is required
- Your clinician’s risk-benefit assessment
Many people continue GLP-1 safely after gallbladder removal under supervision.
When to seek urgent medical help
- Severe upper right abdominal pain lasting more than 1–2 hours
- Fever or chills
- Yellowing of the eyes (jaundice)
- Persistent vomiting
If symptoms escalate, seek urgent care.
Digestive support during recovery (educational only)
After surgery and during dietary transition, some people explore gentle digestion support.
Browse digestive support options at Lily & Loaf
Supplements do not prevent gallstones and do not replace medical care.
FAQs
1. Can GLP-1 medications increase gallstone risk?
Yes indirectly, through accelerated weight loss in some individuals.
2. Is rapid weight loss the main factor?
Speed of fat loss appears to be a major driver.
3. Are gallstones common on Mounjaro?
They are recognised but not common for most users.
4. Can gallstones resolve without surgery?
Small stones may remain silent, but obstructive stones require treatment.
5. Can you restart GLP-1 after gallbladder removal?
Often yes, under clinician supervision.
6. Does diet influence gallstone risk?
Extreme calorie restriction can increase risk.
7. Does slower weight loss reduce risk?
Gradual weight loss may reduce bile chemistry disruption.
8. Are women more at risk?
Gallstones are more common in women overall.
9. Can gallstones cause chest pain?
Yes, pain can radiate and mimic other conditions.
10. Is back pain common with gallstones?
Right shoulder blade pain is common.
11. Should everyone on GLP-1 worry?
No. Most people do not develop gallstones.
12. Does exercise reduce risk?
Regular activity may support metabolic health.
13. Can dehydration influence bile concentration?
Hydration supports overall digestive health.
14. Are older adults at higher risk?
Risk increases with age.
15. Is NHS gallbladder surgery common?
Yes, cholecystectomy is a common emergency procedure in the UK.
Disclaimer: This article shares lived experience and educational context. It does not replace professional medical advice.
