Ozempic (semaglutide) has helped millions of people better manage type 2 diabetes and achieve significant weight loss. This weekly injection reduces appetite, slows digestion, and improves blood sugar control for many users. However, one unwanted side effect that appears more often than expected is the formation of gallstones.
Gallstones are hard deposits that develop inside the gallbladder, a small organ that stores bile. When these stones block bile flow, they can cause severe pain, inflammation, or even require emergency surgery. Reports of gallbladder problems increased noticeably after Ozempic became widely used.
The key question many patients and doctors ask is: why does Ozempic cause gallstones? The answer lies mainly in the rapid weight loss the medication creates, combined with changes in how the gallbladder works during treatment. Understanding this link helps users recognize early warning signs and take steps to lower their risk.
How Ozempic Leads to Rapid Weight Loss
Ozempic belongs to the GLP-1 receptor agonist class of drugs. It mimics a natural hormone that signals fullness after eating and slows the rate at which food leaves the stomach. As a result, most users naturally eat much fewer calories each day.
Clinical studies show average weight loss of 12–18% of starting body weight over 12–18 months on semaglutide. Some people lose 20–25% or more, especially when combining the medication with diet and exercise changes. This amount of weight reduction happens much faster than with most traditional diets.
Rapid weight loss from any method increases the chance of gallstone formation. Ozempic simply makes this rapid loss more common and more pronounced because of its strong appetite-suppressing effect.
The Basic Science of Gallstone Formation
The gallbladder stores bile, a fluid made by the liver to help digest fats. When you eat a meal containing fat, the gallbladder squeezes and releases bile into the small intestine.
Gallstones form when bile contains too much cholesterol, too much bilirubin, or not enough bile salts to keep everything dissolved. The three main types are:
- Cholesterol stones (most common, yellowish, made mostly of hardened cholesterol)
- Pigment stones (smaller, dark, made of bilirubin)
- Mixed stones (combination of both)
Rapid weight loss disturbs the normal balance of these components in bile, making stones more likely to develop.
Why Rapid Weight Loss Increases Gallstone Risk
During significant and fast weight loss, the liver secretes more cholesterol into bile. At the same time, the amount of bile salts (which help dissolve cholesterol) may not increase enough to balance it.
The gallbladder also contracts less frequently when people eat much smaller meals or skip meals due to reduced appetite. Less frequent emptying allows bile to sit longer inside the gallbladder, giving cholesterol more time to crystallize into stones.
Studies of very-low-calorie diets and bariatric surgery show the same pattern: the faster and larger the weight loss, the higher the risk of new gallstones. Ozempic creates similar conditions by promoting quick, substantial fat loss.
How Ozempic Specifically Contributes to This Risk
Ozempic causes gallstones mainly through three overlapping mechanisms:
- Rapid reduction in body fat
Losing large amounts of fat quickly floods the liver with cholesterol from broken-down fat cells. This extra cholesterol enters bile and raises the risk of stone formation. - Reduced gallbladder emptying
GLP-1 drugs like Ozempic suppress appetite so strongly that many people eat small, low-fat meals or skip meals. Infrequent gallbladder contractions mean bile stagnates longer, increasing crystallization risk. - Changes in bile composition
Weight loss alters the ratio of cholesterol to bile salts in bile. During the active weight-loss phase, this imbalance favors cholesterol supersaturation and stone development.
Clinical trials and real-world data confirm that gallbladder-related events (gallstones, cholecystitis, cholecystectomy) occur more frequently with semaglutide than with placebo, especially during the first 6–12 months of treatment.
Who Is at Higher Risk of Gallstones on Ozempic?
Certain factors make gallstone formation more likely while taking Ozempic:
- Starting with a higher body mass index (BMI >35)
- Female sex (women are 2–3 times more likely to develop gallstones overall)
- Age over 40
- Rapid weight loss (>1.5 kg per week)
- History of gallstones or gallbladder removal in family
- Very low-fat diet during treatment
- Pre-existing metabolic conditions (insulin resistance, high triglycerides)
Women who have had multiple pregnancies or who use hormone replacement therapy also face higher baseline risk.
Early Signs and Symptoms of Gallstones
Gallstones do not always cause symptoms right away. When they do, common warning signs include:
- Sudden, intense pain in the upper right abdomen or center of the abdomen
- Pain that radiates to the right shoulder or back
- Nausea and vomiting after eating fatty foods
- Bloating, indigestion, or heartburn that worsens after meals
- Fever, chills, or jaundice (yellow skin/eyes) if a stone blocks the bile duct
These attacks (biliary colic) can last from 30 minutes to several hours. If symptoms persist or fever develops, immediate medical attention is required.
Prevention Strategies While Taking Ozempic
While rapid weight loss always carries some gallstone risk, several practical steps can help lower the chances:
- Lose weight gradually when possible (aim for 0.5–1 kg per week after the initial phase)
- Eat small amounts of healthy fats regularly (e.g., a little olive oil, avocado, or nuts) to encourage gallbladder emptying
- Include fiber-rich foods (vegetables, whole grains, legumes) to support healthy bile flow
- Stay well-hydrated throughout the day
- Avoid very low-fat or crash diets during treatment
- Discuss preventive medication (ursodiol) with your doctor if you have multiple risk factors
Regular check-ups with blood tests and ultrasound monitoring are recommended for high-risk patients.
Summary
Ozempic causes gallstones primarily because of the rapid, significant weight loss it produces in many users. Fast fat breakdown floods the liver with cholesterol, which enters bile and raises the risk of stone formation. At the same time, reduced meal size and frequency cause the gallbladder to empty less often, allowing bile to stagnate and cholesterol to crystallize.
This risk is well-known with any rapid weight-loss method, including very-low-calorie diets and bariatric surgery. Ozempic simply makes substantial weight loss more common and more pronounced due to its strong appetite-suppressing effect. Women, older adults, and those with pre-existing metabolic risk factors face higher chances.
Most gallbladder problems appear during the active weight-loss phase (first 6–18 months). Staying hydrated, eating small amounts of healthy fats, and avoiding extreme low-fat diets can help reduce risk. Anyone experiencing severe abdominal pain, nausea, or other gallstone symptoms should seek medical care promptly.
FAQ
Why are gallstones more common during Ozempic treatment?
Rapid weight loss releases extra cholesterol into bile while the gallbladder contracts less often due to smaller meals. This combination favors gallstone formation, especially in the first 6–18 months.
Does everyone on Ozempic develop gallstones?
No. Only a minority of users experience gallbladder problems. Risk is higher with very rapid weight loss, female sex, older age, and certain metabolic conditions.
Can I prevent gallstones while taking Ozempic?
You can lower your risk by losing weight more gradually, including small amounts of healthy fats in meals, staying hydrated, and eating fiber-rich foods. Discuss preventive medication with your doctor if you have multiple risk factors.
What should I do if I get severe pain while on Ozempic?
Seek medical attention immediately if you have intense upper-right abdominal pain, nausea, vomiting, fever, or jaundice. These symptoms may indicate gallstones or gallbladder inflammation that needs urgent evaluation.
Will stopping Ozempic make existing gallstones go away?
No. Once gallstones have formed, stopping the medication does not dissolve them. Treatment may involve medication (ursodiol), dietary changes, or surgery depending on symptoms and stone size.
Hello Friends!
My name is Ahmad, reading books and gaining knowledge about Health, skin and their conditions is my passion and I am here to share my knowledge and experience with you. I hope it’s very helpful for you.
Thank you very much.