Mounjaro is made with tirzepatide. Ozempic is made with semaglutide. Both are FDA-approved medicines for type 2 diabetes, and each label covers its own uses and ages.
Each label lists the side effects seen in that product's own placebo-controlled trials. The tables below copy those numbers. Placebo means a shot with no medicine in it. A problem in a table is not proof that the medicine caused it.
The two tables come from separate trials with different people and different lengths. They do not come from one trial that tested Mounjaro and Ozempic against each other.
The boxed warning on each label
- Mounjaro (tirzepatide): The Mounjaro label has a boxed warning, FDA's strongest kind. Tirzepatide caused thyroid C-cell tumors in rats. It is not known whether it causes them in people, including medullary thyroid cancer (MTC). People with a personal or family history of MTC, or with a condition called MEN 2, must not use it. The label lists signs of a thyroid tumor to watch for: a lump in the neck, trouble swallowing, shortness of breath, or hoarseness that does not go away.
- Ozempic (semaglutide): The Ozempic label has a boxed warning, FDA's strongest kind. Semaglutide caused thyroid C-cell tumors in rodents. It is not known whether it causes them in people, including medullary thyroid cancer (MTC). People with a personal or family history of MTC, or with a condition called MEN 2, must not use it. The label lists signs of a thyroid tumor to watch for: a lump in the neck, trouble swallowing, shortness of breath, or hoarseness that does not go away.
Mounjaro vs Ozempic: side effect tables
Both labels list problems that reached 5% of people on the medicine and were more common than on placebo. The Mounjaro middle column shows the lowest and highest share across three dose groups. The Ozempic middle column covers two dose groups, so one Ozempic group can be under 5%.
A problem missing from one table may still have happened, below 5% or no more often than on placebo. Low blood sugar is left out of both tables. It was more likely when either medicine was taken with insulin or a diabetes medicine called a sulfonylurea.
Compare each Mounjaro or Ozempic number with its own placebo number, not with the other table.
Mounjaro label
Mounjaro trials in adults with type 2 diabetes 40 weeks
Adults with type 2 diabetes in 2 trials. One tested Mounjaro alone. The other added it to long-acting insulin, with or without metformin. 718 adults took Mounjaro in three dose groups and 235 took placebo.
| Reported problem | Mounjaro groups | Placebo |
|---|---|---|
| Nausea | 12% to 18% | 4% |
| Diarrhea | 12% to 17% | 9% |
| Less appetite | 5% to 11% | 1% |
| Vomiting | 5% to 9% | 2% |
| Constipation | 6% to 7% | 1% |
| Indigestion (dyspepsia) | 5% to 8% | 3% |
| Belly pain | 5% to 6% | 4% |
Source for Mounjaro trials in adults with type 2 diabetes: Mounjaro prescribing information on DailyMed , label revised .
Ozempic label
Ozempic trials in adults with type 2 diabetes 30 weeks
Adults with type 2 diabetes in 2 trials. One tested Ozempic alone. The other added it to long-acting insulin. 521 adults took Ozempic in two dose groups and 262 took placebo.
| Reported problem | Ozempic groups | Placebo |
|---|---|---|
| Nausea | 15.8% to 20.3% | 6.1% |
| Vomiting | 5.0% to 9.2% | 2.3% |
| Diarrhea | 8.5% to 8.8% | 1.9% |
| Belly pain | 5.7% to 7.3% | 4.6% |
| Constipation | 3.1% to 5.0% | 1.5% |
Source for Ozempic trials in adults with type 2 diabetes: Ozempic prescribing information on DailyMed , label revised .
What these numbers do not show
- The labels say side-effect rates from one medicine's trials cannot be directly compared with rates from another medicine's trials.
- Both labels list more warnings, and problems reported after approval, such as pancreatitis that can be deadly and blocked bowels. How often these happen is not known.
- Trials can miss rare harms and harms that take years to appear.
- These numbers describe Mounjaro and Ozempic. They do not describe compounded tirzepatide or semaglutide, or products sold online as research peptides.
Full tables, notes, and warnings
Report a side effect
You can report a suspected side effect to the FDA at 1-800-FDA-1088 or through FDA MedWatch . If a reaction feels serious, get medical care first.
Other label comparisons
- Zepbound vs Wegovy: side effects in the weight-management labels
- Mounjaro vs Zepbound: the same medicine in the diabetes and weight labels
- Ozempic vs Wegovy: the same medicine in the diabetes and weight labels
- Saxenda vs Zepbound: side effects in the weight-management labels
- Victoza vs Ozempic: side effects in the type 2 diabetes labels
- Saxenda vs Wegovy: side effects in the weight-management labels
- Forteo vs Tymlos: side effects in the osteoporosis labels