GLP-1 side effects: what is common and when to seek help
Guide to Wegovy and Mounjaro digestive effects, hydration, and signs to seek medical attention.
The essentials in less than a minute
- Nausea, diarrhea, constipation, vomiting and abdominal pain are among the most common effects.
- They tend to appear more during the start or increase of doses, but they should not normalize if they are intense or persistent.
- Strong and sustained abdominal pain, dehydration, allergic reaction or visual changes require rapid evaluation.
- Safety also depends on diabetes, other medications, history, and following the indicated escalation.
Common digestive effects
The EMA describes nausea, vomiting, diarrhea, constipation and abdominal pain among the common effects of Wegovy and Mounjaro. The intensity varies and many discomforts are concentrated around dose changes.
| Annoyance | General measurement | Check if… |
|---|---|---|
| Nausea | Small portions, eat slowly | You can’t hydrate or it gets worse |
| Vomiting/diarrhea | Liquids in sips | You urinate little, dizziness or it persists |
| Constipation | Water, movement, fiber tolerated | Severe pain, bloating, or vomiting |
| Ebb/fullness | Avoid heavy meals and go to bed afterwards | Chest pain or difficulty swallowing |
Signs that require quick attention
Don’t wait if it appears
Severe and persistent abdominal pain that may radiate to the back; swelling of the face or throat, difficulty breathing; fainting; inability to retain fluids; or new visual changes, especially if you have diabetes.
Pancreatitis is rare but important. The leaflet also includes serious allergic reactions and specific precautions. The complete list depends on the product and should be consulted in its official information.
Hypoglycemia and interaction with other treatments
The risk of low glucose increases especially when these medications are used together with insulin or sulfonylureas. The doctor may need to adjust the treatment and order self-monitoring. Sweating, shaking, intense hunger, confusion, or weakness may be signs.
Do not reduce insulin or other medications on your own. Likewise, do not combine GLP-1 products or use two brands to accelerate results.
What to register for review
A brief record allows you to distinguish a temporary discomfort from a pattern that requires de-escalation, a change of plan, or testing. The consultation must assess benefit and tolerance together.
Medically reviewed by Dr Paulo
Medical reviewer for Costa Medical Services. Clinical coherence, safety and source quality reviewed.
✓ Ordem dos Médicos Portugal 69376 · Review August 30, 2026Official and clinical sources
- EMA: Wegovy EPAR and adverse effects
- EMA: Mounjaro EPAR and adverse effects
- EMA: Wegovy, product information
- EMA: Mounjaro, product information
Regulatory information may change. Before publishing in WordPress, you should double-check the current version of the SmPC and leaflet.
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