Semaglutide Side Effects
Medically reviewed by Dr. Jonathan Snipes, MD
Reviewed for clinical accuracy · Last reviewed July 22, 2026 · Review policy
Quick answer
The most common Semaglutide side effects are nausea and vomiting, diarrhea, constipation, and are usually mild and dose-related. Serious effects are less common; the full breakdown and cautions are below.
| Effect | Frequency |
|---|---|
| NauseaUsually early and dose-dependent | Common |
| Vomiting, diarrhea, constipation | Common |
| Abdominal pain, reflux | Less common |
| Gallbladder problems (gallstones) | Less common |
| Acute pancreatitis | Rare |
| Thyroid C-cell tumorsBoxed warning based on rodent data; contraindicated with personal/family history of medullary thyroid carcinoma or MEN 2 | Rare |
Most semaglutide side effects are gastrointestinal and appear during dose escalation. They tend to ease as the body adapts, which is the main reason for the slow titration schedule. Serious effects are uncommon but important: gallbladder disease, rare pancreatitis, and a boxed warning for thyroid C-cell tumors observed in rodents. Because of that warning, it is contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.
Report severe or persistent abdominal pain, signs of an allergic reaction, or symptoms of pancreatitis to a clinician promptly. Side-effect profiles for compounded semaglutide can differ from the FDA-approved products depending on formulation and source.
Frequently asked questions
What are the most common Semaglutide side effects?+
The most common Semaglutide side effects are nausea and vomiting, diarrhea, constipation. See the full frequency table above for less common and rare effects.
Is Semaglutide safe?+
Semaglutide is FDA-approved and, used under medical supervision, is generally tolerated, but it is not risk-free: it has side effects and specific contraindications. Discuss your history with a clinician.