Two conditions under one warning
Section 5.3, “Acute Gallbladder Disease”, covers two related problems. Cholelithiasis means stones in the gallbladder, the small organ under the liver that stores bile; cholecystitis means inflammation of the gallbladder, which gallstones can cause. [1] The EU and Canadian documents report the same two events, with slightly different placebo figures in the EU pool of STEP 1–4. [2][3]
| Event, group and source | Placebo | Wegovy® injection |
|---|---|---|
| Gallstones, adults, US and Canada [1][3] | 0.7% | 1.6% |
| Gallbladder inflammation, adults, US and Canada [1][3] | 0.2% | 0.6% |
| Gallstones and inflammation, adults, EU STEP 1–4 [2] | 1.1% and 0.3% | 1.6% and 0.6% (“common”) |
| Gallstones, adolescents 12 and older [1] | 0% | 3.8% |
| Gallbladder inflammation, adolescents [1] | 0% | 0.8% |
Not explained by weight loss alone
Gallstones become more likely with substantial or rapid weight loss, and the label says so. It then adds an important qualifier: acute gallbladder disease was still more frequent on Wegovy® than on placebo after accounting for how much weight people lost. [1] The counselling section makes the same two points for patients: large or rapid weight loss can raise the risk, but gallbladder disease can also occur without either. [1] A slow, steady pace of loss is therefore not a guarantee.
If gallstones are suspected, section 5.3 calls for gallbladder studies and appropriate follow-up, and prescribers are asked to tell patients to get in touch if gallbladder disease is suspected. [1]
Higher in teenagers
Section 5.3 states that gallstones and gallbladder inflammation were more frequent in teenagers on the injection than in adults: in the 68-week adolescent trial, 3.8% on Wegovy® developed gallstones and nobody on placebo did, shown as 4% in the rounded safety table. [1] The Canadian monograph makes the same comparison, 3.8% of adolescents against 1.6% of adults. [3]
The same trial reported rises in the liver enzyme ALT of five times the upper limit of normal or more in 3% of teenagers on Wegovy® and none on placebo; in some cases other factors, such as gallstones, were involved. [1]
What two meta-analyses add
A 2022 meta-analysis of 76 randomised trials with more than 103,000 participants found GLP-1 medicines were associated with more gallbladder or bile-duct disease overall (risk ratio 1.37), including gallstones and cholecystitis. The increase was larger in weight-loss trials (risk ratio 2.29) than in diabetes trials, and was seen at higher doses and with longer use but not at lower doses or shorter use. [4]
A 2025 meta-analysis of 55 placebo-controlled trials put the gallstone risk ratio at 1.46, about 2 extra cases for every 1,000 people treated, with a stronger effect in obesity trials and high-dose formulations, although those subgroup differences were not statistically significant. [5] Both analyses pooled several medicines, so they describe the class rather than Wegovy® alone.
Why gallstones may form: three layers
- In the label: large or rapid weight loss raises the risk, yet Wegovy® showed more gallbladder disease even after accounting for weight lost. [1] The label does not explain the extra risk.
- In research: the meta-analyses link higher risk with weight-loss doses and longer treatment, [4][5] which fits a dose- and time-related effect but does not identify a mechanism.
- General background: NIH explains that during fasting or fast weight loss the liver releases extra cholesterol into bile and the gallbladder may not empty properly, and that losing and regaining weight repeatedly also raises the chance of gallstones. [7]
Who else is at risk, and look-alike pain
NIH lists other groups with a higher chance of gallstones: women, especially with extra oestrogen from pregnancy, hormone therapy or birth control pills; older people; people with a family history; and some ethnic groups. [9] Most gallstones are “silent” and cause no symptoms; a gallbladder attack happens when a stone blocks a bile duct, usually causing pain in the upper right belly that can last several hours. [6]
Gallstone pain can resemble appendicitis, ulcers, pancreatitis or reflux. [6] The Wegovy® Medication Guide treats severe stomach pain that will not settle, sometimes reaching the back, as a possible sign of pancreatitis and says to stop Wegovy® and call your provider straight away. [1] Telling these apart is a job for your clinician.
Symptoms the leaflets list
The US Medication Guide says Wegovy® may cause gallbladder problems, including gallstones, and that some need surgery. It asks you to call your healthcare provider for pain in the upper stomach, yellowing of the skin or the whites of the eyes (jaundice), fever, or clay-coloured stools. [1] The Canadian leaflet asks people to talk to a healthcare professional in all cases of suspected gallstones. [3] Novo Nordisk’s patient page repeats the US symptom list. [8]
Wegovy® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Severe stomach pain that will not settle, sometimes reaching the back | Stop Wegovy® and call your provider right away; emergency care if severe | Emergency | Medication Guide [1] |
| Belly pain lasting several hours with fever or chills, yellow skin or eyes, or tea-coloured urine and pale stools | A doctor right away | Emergency | NIDDK [6] |
| Upper stomach pain, yellowing, fever or clay-coloured stools | Your prescriber, the same day | Today | Medication Guide [1] |
| Sudden pain in the upper stomach or back, often on the right, with nausea, vomiting or indigestion | A healthcare professional in all cases | Today | Canadian leaflet [3] |
| A teenager on Wegovy® with new upper belly pain | Their prescriber promptly | Today | Wegovy® sections 5.3 and 8.4 [1] |
| A history of gallstones, or plans for a very low-calorie diet or weight-loss surgery | Discuss with your prescriber before or during treatment | At your next appointment | NIDDK [7] |
