How common each one is
Label rates vs placebo
| Side effect | Mounjaro | Placebo |
|---|---|---|
| Nausea | 12% to 18% | 4% |
| Diarrhea | 12% to 17% | 9% |
| Decreased appetite | 5% to 11% | 1% |
| Vomiting | 5% to 9% | 2% |
| Heartburn and indigestion | 5% to 8% | 3% |
| Constipation | 6% to 7% | 1% |
| Stomach pain | 5% to 6% | 4% |
| Low blood sugar | Higher with insulin or a sulfonylurea | n/a |
When side effects happen
In the trials, stomach side effects were mostly mild to moderate and most common during the dose-increase weeks. They often flare for a few days after each step up, then ease on the same dose.
How to use it
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These are estimates, not a diagnosis. A clinician can account for your health history and medicines.
Serious warnings on the label
- Pancreatitis. Stop and get care right away for severe stomach pain that won't go away, with or without vomiting, sometimes felt in the back.
- Gallbladder problems. Gallstones and gallbladder inflammation were more common in trials, especially with rapid weight loss. Watch for upper-right belly pain, fever, yellow skin or eyes, or clay-colored stools.
- Low blood sugar. Risk rises when combined with insulin or a sulfonylurea. Signs include shakiness, sweating, fast heartbeat, confusion and dizziness.
- Kidney problems. Vomiting and diarrhea can cause dehydration, which can worsen kidney function. Drink fluids and call your prescriber if you can't keep them down.
- Serious allergic reactions. Get emergency help for swelling of the face, lips, tongue or throat, trouble breathing or a severe rash.
- Severe stomach problems. Not recommended if you already have severe gastroparesis (very slow stomach emptying).
- Aspiration during anesthesia. Tell your care team you take a GLP-1 medicine before any surgery or procedure that uses anesthesia or deep sedation, because food can stay in the stomach longer.
Common questions
What is the most common side effect of Mounjaro?
Nausea, reported in 12% to 18% of people vs 4% on placebo.
How long do Mounjaro side effects last?
Stomach side effects are most common in the weeks after starting and after each dose increase, and usually ease over days to weeks on the same dose. Tell your prescriber if they don't.
Which Mounjaro side effects are serious?
Severe stomach pain that won't go away, signs of pancreatitis or gallbladder problems, severe allergic reactions, dehydration and kidney problems, and a lump in the neck. Get care right away for these.
Sources
Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error