Research information only, not medical advice. Tirzepatide's most common side effects are gastrointestinal — nausea, diarrhoea, vomiting and constipation — consistent with the GIP/GLP-1 class. Its label carries a boxed warning for thyroid C-cell tumours. In pooled trials, serious adverse events were comparable to placebo.
Tirzepatide is an FDA-approved drug (Mounjaro for type 2 diabetes, Zepbound for weight management). The most common adverse effects reported in its trials are gastrointestinal — nausea, diarrhoea, vomiting and constipation — and tend to be greatest during dose escalation. In a 2026 network meta-analysis, gastrointestinal adverse events rose with treatment (relative risk 1.33-1.91) while serious adverse events stayed comparable to placebo. The label also carries a boxed warning for thyroid C-cell tumours. 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 Tirzepatide research overview . Related: tirzepatide dosage , tirzepatide before and after .
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Frequently asked questions
- What are the most common side effects of tirzepatide?
- Gastrointestinal effects — nausea, diarrhoea, vomiting and constipation — are the most commonly reported, usually greatest while the dose is being increased.
- Are tirzepatide's serious side effects common?
- In a 2026 network meta-analysis, serious adverse events were comparable to placebo. The label carries a boxed warning for thyroid C-cell tumours. This is trial data, not medical advice.
Updated · sourced to primary documents