Zepbound is made with tirzepatide. Wegovy is made with semaglutide. Both are FDA-approved medicines for weight management, and each label lists other uses too.
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 Zepbound and Wegovy against each other.
The boxed warning on each label
- Zepbound (tirzepatide): The Zepbound 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.
- Wegovy (semaglutide): The Wegovy 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.
Stomach and bowel problems, and stopping the medicine
- Zepbound label: in the weight trials, 56% of adults on Zepbound and 30% on placebo had a stomach or bowel problem. Across the three dose groups, 4.8% to 6.7% stopped Zepbound because of side effects, compared with 3.4% on placebo.
- Wegovy label: in the weight trials in adults, 73% on Wegovy and 47% on placebo had a stomach or bowel problem. 6.8% stopped Wegovy because of side effects, compared with 3.2% on placebo.
Compare each number with its own placebo number, not with the other label.
Zepbound vs Wegovy: side effect tables
The Zepbound label lists problems in at least 2% of adults on Zepbound that were more common than on placebo. Its table here shows the 12 the label names as most common. The middle column shows the lowest and highest share across three dose groups.
The Wegovy label lists problems in at least 2% of adults on Wegovy that were more common than on placebo. Its table here shows the ones that reached 5%. It is for the usual-dose shot, not Wegovy HD or the Wegovy tablet.
A problem missing from one table may still have happened. The Zepbound label also lists dizziness, gas, bloated belly, and low blood pressure, each more common than on placebo. They are in the less common table on the tirzepatide side effects page.
The Wegovy label also lists irritated stomach lining (gastritis), stomach flu from a virus, hair loss, and changed skin feeling in 2% to 4% of adults, more often than on placebo. They are in the less common table on the semaglutide page.
Low blood sugar is only in the Wegovy table, where only people with type 2 diabetes were counted. The Zepbound label reports it separately. In its trial of adults with type 2 diabetes, 4.2% on Zepbound and 1.3% on placebo had a blood sugar below 54 mg/dL.
In that Zepbound trial, low blood sugar happened to 10.3% of people on Zepbound who also took a diabetes medicine called a sulfonylurea, and 2.1% of those who did not. For semaglutide, low blood sugar was more likely when it was taken with insulin or a sulfonylurea. The Zepbound label says it can cause low blood sugar, including in adults without type 2 diabetes.
Compare each Zepbound or Wegovy number with its own placebo number.
Zepbound label
Zepbound trials in adults with obesity or overweight Up to 72 weeks
Adults with obesity or overweight in 2 trials. One trial included only people with type 2 diabetes; the other left them out. 2,519 got Zepbound in three dose groups and 958 got placebo.
| Reported problem | Zepbound groups | Placebo |
|---|---|---|
| Nausea | 25% to 29% | 8% |
| Diarrhea | 19% to 23% | 8% |
| Constipation | 11% to 17% | 5% |
| Vomiting | 8% to 13% | 2% |
| Belly pain | 9% to 10% | 5% |
| Indigestion (dyspepsia) | 9% to 10% | 4% |
| Shot-site reactions, like redness, itching, or bruising | 6% to 8% | 2% |
| Tiredness or weakness (fatigue) | 5% to 7% | 3% |
| Allergic reactions, mostly rash or itching | 5% | 3% |
| Burping | 4% to 5% | 1% |
| Hair loss | 4% to 5% | 1% |
| Acid reflux (GERD) | 4% to 5% | 2% |
Source for Zepbound trials in adults with obesity or overweight: Zepbound prescribing information on DailyMed , label revised .
Wegovy label
Wegovy trials in adults with obesity or overweight Up to 68 weeks
Adults with obesity or overweight in 3 trials. 2,116 got Wegovy and 1,261 got placebo. 19% had type 2 diabetes.
| Reported problem | Wegovy | Placebo |
|---|---|---|
| Nausea | 44% | 16% |
| Diarrhea | 30% | 16% |
| Vomiting | 24% | 6% |
| Constipation | 24% | 11% |
| Belly pain | 20% | 10% |
| Headache | 14% | 10% |
| Tiredness or weakness (fatigue) | 11% | 5% |
| Indigestion (dyspepsia) | 9% | 3% |
| Dizziness | 8% | 4% |
| Bloated belly | 7% | 5% |
| Burping | 7% | Under 1% |
| Low blood sugar (only people with type 2 diabetes were counted) | 6% | 2% |
| Gas | 6% | 4% |
| Stomach flu (gastroenteritis) | 6% | 4% |
| Acid reflux (GERD) | 5% | 3% |
Source for Wegovy trials in adults with obesity or overweight: Wegovy 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.
- Each label lists more warnings than these tables show. The full tables, notes, and warnings are linked below.
- Trials can miss rare harms and harms that take years to appear.
- These numbers describe Zepbound and Wegovy. 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
- Mounjaro vs Ozempic: side effects in the type 2 diabetes 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