GLP-1 Long-Term Side Effects: What Years of Data Show
The long-term warnings are the same across GLP-1 labels: thyroid C-cell tumors seen in rodents, pancreatitis, gallbladder disease and kidney injury from fluid loss.
- Nausea, lowest label rate
- 18% Mounjaro
- Nausea, highest label rate
- 44% Byetta
- Labels compared
- 10
Half-life and weight loss overview
In days, a drug's half-life tells how long your body needs to remove half of one dose. This comes from section 12.3 in every FDA label.
Percentage of body weight. On each medicine's own page, compare the result with its placebo, since the trials used different doses and lengths.
The serious warnings explained simply
These warnings appear on the Wegovy label. Every other GLP-1 label includes the same class warnings.
- Boxed warning about thyroid C-cell tumors. This medicine caused thyroid C-cell tumors in rodents. People are not known to develop them from this medicine. Do not use if you or a family member has had medullary thyroid cancer (MTC) or if you have MEN 2.
- Pancreatitis. This medicine may inflame the pancreas. Stop taking it and seek care if severe stomach pain continues and sometimes reaches your back.
- Gallbladder disease. Gallstones and inflammation of the gallbladder may occur. Report fever, yellow skin or eyes, and upper right belly pain.
- Low blood sugar. If you use it with insulin or a sulfonylurea, low blood sugar is more likely, and those doses may need to be lowered.
- Kidney injury from fluid loss. Fluid loss from vomiting or diarrhea may cause kidney injury. Report heavy fluid loss. Drink fluids.
- Severe stomach and gut reactions. Stomach and gut side effects often occur and can be severe. This medicine is not recommended if you have severe gastroparesis.
- Allergic reactions that are severe Reports include serious allergic reactions, some with swelling of the throat, lips or face. Stop taking it and get immediate help if they occur.
- Diabetic eye disease getting worse. In people with type 2 diabetes, diabetic eye disease can worsen, particularly when blood sugar drops quickly. Eye checks matter if you already have it.
- Faster heart rate. Can raise resting heart rate. Tell your doctor if your heart races or pounds while you are at rest.
- Food that reaches the lungs during anesthesia or sedation Food can remain in your stomach longer, which is important during deep sedation or anesthesia. Tell your care team before you have any procedure.
Source: FDA label (DailyMed).
Source: FDA label (DailyMed).
Label rates compared with placebo for long-term GLP-1 side effects
The labels report separate placebo-controlled trials, each involving a different population. The rows offer rough guidance only and do not provide a head-to-head result.
| Medicine | Nausea | Vomiting | Diarrhea | Constipation | Stomach pain | Heartburn and indigestion | Trial group |
|---|---|---|---|---|---|---|---|
 Ozempic | 20.3% | 9.2% | 8.8% | 5% | 7.3% | Not listed | Adults with type 2 diabetes |
 Wegovy | 44% | 24% | 30% | 24% | 20% | 9% | Adults with obesity or overweight (weight management) |
 Rybelsus | 20% | 8% | 10% | 6% | 11% | Not listed | Adults with type 2 diabetes |
 Mounjaro | 18% | 9% | 17% | 7% | 6% | 8% | Adults with type 2 diabetes |
 Zepbound | 29% | 13% | 23% | 17% | 10% | 10% | Adults with obesity or overweight (weight management) |
 Foundayo | 35% | 24% | 25% | 27% | 14% | 16% | Adults with obesity or overweight (weight management) |
 Trulicity | 21.1% | 12.7% | 12.6% | Not listed | 9.4% | 5.8% | Adults with type 2 diabetes |
 Saxenda | 39.3% | 15.7% | 20.9% | 19.4% | 5.4% | 9.6% | Adults with obesity or overweight (weight management) |
 Victoza | 20% | 9% | 12% | 5% | Not listed | 7% | Adults with type 2 diabetes |
| Byetta | 44% | 13% | 13% | Not listed | Not listed | 6% | Adults with type 2 diabetes |
Sources: Ozempic label (DailyMed), Wegovy label (DailyMed), Rybelsus label (DailyMed), Mounjaro label (DailyMed), Zepbound label (DailyMed), Foundayo label (DailyMed), Trulicity label (DailyMed), Saxenda label (DailyMed), Victoza label (DailyMed), Byetta label (DailyMed).