Patient guide · Reviewed May 2026
GLP-1 Medications and Gallstones — What Australian Patients Need to Know
If you are on Ozempic, Wegovy, or Mounjaro and you have experienced right-sided abdominal pain after eating, or you have heard that these medications can cause gallbladder problems — you are right to want clear information.
GLP-1 receptor agonists are associated with an increased risk of gallbladder disease, including gallstone formation. This is a known and documented side effect class — not rare, not trivial, and not separate from liver health. The gallbladder sits directly beneath the liver, and gallbladder disease in the context of GLP-1 therapy has direct implications for liver function and monitoring.
This article explains why GLP-1 medications increase gallstone risk, what symptoms to watch for, how the gallbladder and liver are connected, and what monitoring is appropriate.
Published 2026-05-01 · Clinically reviewed 2026-05-31
Patient guide · Reviewed May 2026
Why GLP-1 Medications Increase Gallstone Risk
The link between GLP-1 medications and gallstones operates through two main mechanisms — the medication itself and the rapid weight loss it produces.
The link between GLP-1 medications and gallstones operates through two main mechanisms — the medication itself and the rapid weight loss it produces.
Mechanism 1 — The GLP-1 Effect on Gallbladder Motility
GLP-1 suppresses the release of CCK (cholecystokinin), which reduces gallbladder contraction. As a result, bile remains in the gallbladder for longer periods, increasing the risk of cholesterol crystallisation and gallstone formation.
CCK is the hormone that signals the gallbladder to contract and release bile into the small intestine. When this signalling is suppressed by GLP-1 activity, bile stagnates in the gallbladder — a condition called bile stasis. Stagnant bile is more likely to form solid cholesterol crystals, which over time accumulate into gallstones.
GLP-1 medications also reduce FGF19 and GLP-2 signalling, which further impairs gallbladder contraction and relaxation — compounding the bile stasis effect.
Mechanism 2 — Rapid Weight Loss and Bile Composition
When patients lose weight quickly, the body processes and eliminates cholesterol more rapidly. That cholesterol can concentrate in bile, which is stored in the gallbladder. Over time it can crystallise and form gallstones.
During rapid weight loss, the liver secretes increased cholesterol into bile while simultaneously receiving reduced bile acid output. At the same time, reduced food intake means the gallbladder empties less often. This combination creates bile that is cholesterol-rich and poorly drained, promoting crystallisation and gallstone formation.
This rapid weight loss mechanism is not unique to GLP-1 medications — the same pattern was observed with bariatric surgery decades ago. Any intervention producing rapid weight loss carries gallstone risk.
How Common Is This Problem?
A systematic review and meta-analysis that looked at 76 studies on GLP-1 receptor agonists found that GLP-1s increase the risk of gallstones by 27% and gallbladder inflammation by 36%. The increased risk is higher in patients taking GLP-1s for weight loss compared to diabetes — likely because weight loss doses are higher and weight loss is more rapid.
The highest risk period occurs during the first 6–12 months of GLP-1 therapy when weight loss is most rapid. Patients losing more than 3 pounds (1.4kg) per week face the greatest gallstone formation risk.
A 27% increased risk does not mean one in four patients develops gallstones. It means the baseline risk — already present in the general population — increases by 27%. Most patients on GLP-1 therapy do not develop symptomatic gallstones. But the risk is real and higher than in the non-GLP-1 population, which is why awareness and monitoring matter.
Patient guide · Reviewed May 2026
The Gallbladder-Liver Connection
The gallbladder sits directly beneath the right lobe of the liver and shares the biliary tree — the ductal system that drains bile from the liver through the…
The gallbladder sits directly beneath the right lobe of the liver and shares the biliary tree — the ductal system that drains bile from the liver through the gallbladder and into the small intestine. Gallbladder disease is therefore intimately connected to liver health.
When gallstones form and obstruct the bile duct, bile backs up into the liver — causing a rise in liver enzymes (particularly ALP, GGT, and bilirubin) that can be confused with or complicate the monitoring of MASLD.
For patients who already have MASLD and are on a GLP-1 medication for liver benefit, a gallstone-related bile duct obstruction can produce liver enzyme elevations that may be misattributed to liver disease progression or drug-induced liver injury — when the actual cause is biliary obstruction. This is why understanding the gallbladder-liver interaction matters in clinical monitoring.
If you have MASLD and develop new right upper quadrant pain with elevated ALP or GGT on blood tests, gallbladder disease should be excluded — this typically requires an abdominal ultrasound, not just liver elastography.
Symptoms of Gallbladder Disease on GLP-1 Medications
The classic presentation of symptomatic gallstones (biliary colic) is:
- Sharp or cramping pain in the right upper abdomen, particularly after eating a fatty meal
- Pain that may radiate to the right shoulder blade or back
- Nausea with or without vomiting
- Pain lasting 30 minutes to several hours before resolving
More serious gallbladder complications — acute cholecystitis (gallbladder inflammation) or bile duct obstruction — present with:
- Persistent severe right upper abdominal pain (not resolving within 6 hours)
- Fever and chills
- Jaundice (yellowing skin or eyes)
- Dark urine
Randomised trial data show GLP-1 receptor agonists are associated with increased risk of gallbladder and biliary disease, especially at higher doses, longer use, and when used for weight loss. Acute cholecystitis in the context of GLP-1 therapy typically requires surgical management — gallbladder removal. In most cases, surgery is straightforward laparoscopic cholecystectomy. In rare cases, complications can be more serious.
Symptoms of acute cholecystitis require same-day medical review. Do not wait.
Patient guide · Reviewed May 2026
Who Is at Highest Risk?
Certain patient populations face elevated baseline risks. Women develop gallstones at twice the rate of men, particularly those over 40 or with previous…
Certain patient populations face elevated baseline risks. Women develop gallstones at twice the rate of men, particularly those over 40 or with previous pregnancies. Patients with existing gallstones, even asymptomatic ones, have significantly higher complication rates when starting GLP-1 therapy.
Additional risk factors specific to GLP-1 therapy:
- Rapid weight loss (more than 1.5kg per week) — a GLP-1 therapy risk rather than a contraindication
- High-dose GLP-1 medications (Wegovy 2.4mg, Mounjaro 15mg) versus lower doses
- Longer duration of therapy
- Pre-existing conditions: high cholesterol, diabetes, family history of gallstones, obesity
What to Do — Practical Steps for Australian Patients
Before starting a GLP-1 medication: If you have a history of gallbladder disease, symptomatic gallstones, or previous biliary colic, inform your prescribing GP. A decision about whether to assess the gallbladder with ultrasound before starting — particularly if you are starting at weight-loss doses — is appropriate clinical practice.
During the first 6–12 months: Be alert to the symptoms described above, particularly right upper abdominal pain after eating. The highest gallstone formation risk is during the rapid weight loss phase.
Gradual dose escalation: Slow, gradual dose escalation reduces the rate of weight loss in the early months, which may reduce gallstone formation risk. This is one of the reasons the dose escalation schedules for these medications are relatively slow.
Dietary considerations: Very low fat diets paradoxically increase gallstone risk because they reduce gallbladder emptying — the gallbladder needs fat intake to contract regularly. A balanced diet with moderate fat intake is more appropriate than an extremely low-fat approach on GLP-1 therapy.
If you develop symptoms: Right upper abdominal pain after eating should be discussed with your GP. An abdominal ultrasound can identify gallstones. If gallstones are present and asymptomatic, monitoring may be appropriate. Symptomatic gallstones typically require surgical removal.
Patient guide · Reviewed May 2026
Gallstones and Liver Monitoring — What to Check
For patients on GLP-1 medications with elevated liver enzymes, gallbladder disease should be excluded when:
For patients on GLP-1 medications with elevated liver enzymes, gallbladder disease should be excluded when:
- ALP and GGT are disproportionately elevated compared to ALT and AST (cholestatic pattern)
- Bilirubin is elevated
- Right upper abdominal pain or discomfort is present
- Liver stiffness on elastography seems inconsistent with blood test results
A standard abdominal ultrasound can identify gallstones, bile duct dilatation, and gallbladder wall thickening — all signs of gallbladder pathology that may explain apparent liver function changes.
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Frequently asked questions
Do Ozempic and Mounjaro cause gallstones?
GLP-1 medications including Ozempic, Wegovy, and Mounjaro are associated with an increased risk of gallstone formation — a 27% increased risk compared to non-GLP-1 users in a meta-analysis of 76 studies. Most patients do not develop symptomatic gallstones, but the risk is real and higher than background.
What are the signs of gallbladder problems on Ozempic?
Right upper abdominal pain particularly after eating, nausea, pain radiating to the right shoulder blade. Severe persistent pain with fever, jaundice, or dark urine indicates a more serious complication requiring urgent medical review.
Can gallstones on Ozempic affect my liver?
Yes — bile duct obstruction from gallstones can cause liver enzyme elevation (particularly ALP and GGT) and, if untreated, serious liver complications. The gallbladder and liver share the biliary tree. Patients monitoring their liver on GLP-1 medications should be aware that elevated liver enzymes may reflect gallbladder disease rather than MASLD progression.
How can I reduce gallstone risk on GLP-1 medications?
Gradual dose escalation reduces the rate of early rapid weight loss. Maintaining moderate fat intake rather than an extremely low-fat diet supports regular gallbladder emptying. Regular physical activity supports bowel and gallbladder movement. Discuss any prior gallbladder history with your GP before starting.
What happens if I get gallstones on Mounjaro?
Asymptomatic gallstones may not require immediate treatment — your GP will advise appropriate monitoring. Symptomatic gallstones causing biliary colic typically require laparoscopic cholecystectomy (gallbladder removal). Whether to continue Mounjaro following gallstone diagnosis is a decision for your GP and specialist.
Sources: JAMA Internal Medicine meta-analysis 2022; Therapeutic Advances in Endocrinology 2025; diabetes.co.uk GLP-1 emergency review (December 2025); Shore Medical Center (March 2026); Doctronic clinical review (April 2026); Hers gallbladder review (November 2025).
This article is for educational purposes only. It does not constitute medical advice. Always consult your GP or a specialist about your individual health circumstances.
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