Is Mounjaro Safe? Warnings, Who Should Not Take It, Long-Term Data
Mounjaro has been FDA-approved since 2022 and was tested in 15,656 people across 3 major trials. Its label carries a boxed warning for thyroid C-cell tumors and 9 other warnings. 2 groups should not take it.
- FDA-approved since
- 2022
- People in its major trials
- 15,656
- Boxed warning
- Thyroid C-cell tumors
Mounjaro in brief
Half-life about 5 days: after 5 d, half is gone, and after five half-lives (25 d) about 3% is left.
In SURPASS-1, people with type 2 diabetes lost 7.8 kg over 40 weeks, compared with 1 kg on placebo.
In US dollars, the monthly price points cover list price and self-pay offers, each listed by the maker on its price page.
Sources: FDA label (DailyMed), healthsystemtracker.org, pricinginfo.lilly.com.
Boxed warning
Boxed warning: the medicine caused thyroid C-cell tumors in rodents. It is not known if it causes them in people. Do not take this medicine if you or a family member has had medullary thyroid cancer (MTC), or if you have MEN 2.
Source: FDA label (DailyMed).
Who should not take Mounjaro?
- Medullary thyroid cancer (MTC) in your personal or family history, or MEN 2.
- You had a serious allergic reaction before, to tirzepatide or to one of the product's ingredients.
Source: FDA label (DailyMed).
Source: FDA label (DailyMed).
How often do serious side effects happen?
These rates came from the label trials. Placebo results from those same trials appear beside them.
| Problem | Label | On the drug | On placebo | More |
|---|---|---|---|---|
| Vomiting |  Mounjaro | 9% (15 mg) | 2% | Not listed |
Source: the Mounjaro label (DailyMed).
Other warnings in the Mounjaro label
- Thyroid C-cell tumors. The medicine caused thyroid C-cell tumors in rodents. It is not known if people get them from it. This medicine is not for anyone who has had medullary thyroid cancer (MTC) personally or in the family, or who has MEN 2.
- Inflammation of the pancreas. This medicine can cause inflammation of the pancreas. When severe stomach pain will not go away, stop taking it and get care.
- Low blood sugar. When you use this medicine with insulin or a sulfonylurea, low blood sugar becomes more likely. The doses of those drugs may need to be lowered.
- Reports include serious allergic reactions. Serious allergic reactions have been reported, including swelling of face, lips or throat. If one occurs, stop the medicine and get help right away.
- Kidney injury from fluid loss. Fluid loss can lead to kidney injury. If you have heavy fluid loss, report it and drink fluids.
- Severe reactions that affect the stomach and gut. Stomach and gut side effects are common, and they can be serious. We do not recommend this medicine for people with severe gastroparesis.
- Diabetic eye disease getting worse. People who have type 2 diabetes can see diabetic eye disease get worse, especially when their blood sugar falls quickly. If you already have it, it is important to have your eyes checked.
- Gallbladder disease. You may develop gallstones or inflammation of the gallbladder. Report any fever, yellow skin or eyes, or belly pain on the upper right side.
- Food entering the lungs during anesthesia or sedation. Under anesthesia or deep sedation, it matters if food remains in the stomach longer. Tell your care team before you have any procedure.
Source: FDA label (DailyMed).
Long-term safety data
The trials looked at hard outcomes rather than weight alone.
| Trial | What it measured | Result | Compared with | Length |
|---|---|---|---|---|
| SURPASS-CVOT | Heart attack, stroke or death from heart disease | 12.2% vs 13.1% 8% lower risk | dulaglutide 1.5 mg (Trulicity) | Not listed |
Source: SURPASS-CVOT (PubMed).