Research information only, not medical advice. Semaglutide's most common side effects are gastrointestinal — nausea, vomiting, diarrhoea and constipation. Its label carries a boxed warning for thyroid C-cell tumours and warnings for pancreatitis and gallbladder disease, and it is contraindicated with a history of medullary thyroid carcinoma or MEN 2.
Semaglutide is an FDA-approved GLP-1 agonist (Ozempic for type 2 diabetes, Wegovy for weight management). The most common adverse effects reported in its large phase 3 trials are gastrointestinal — nausea, vomiting, diarrhoea and constipation. The label carries a boxed warning for thyroid C-cell tumours based on rodent data, contraindicates it in people with a personal or family history of medullary thyroid carcinoma or MEN 2, and adds warnings for pancreatitis and gallbladder disease. This is trial and label information for an approved drug, not medical advice.
For the full evidence base, clinical trials, and regulatory status, see the Semaglutide research overview . Related: semaglutide dosage , semaglutide before and after .
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Frequently asked questions
- What are the most common side effects of semaglutide?
- Gastrointestinal effects — nausea, vomiting, diarrhoea and constipation — are the most commonly reported, usually greatest while the dose is being increased.
- Does semaglutide have a boxed warning?
- Yes — for thyroid C-cell tumours, based on rodent data. It is contraindicated in people with a history of medullary thyroid carcinoma or MEN 2. This is label information, not medical advice.
Updated · sourced to primary documents