Ozempic thyroid warning — the boxed warning for medullary thyroid carcinoma and MEN 2, rodent-vs-human evidence, and who must not take it.
Short answer: Ozempic carries a boxed warning: it caused thyroid C-cell tumors in rodents. Human relevance is unknown, but it's contraindicated in anyone with personal or family history of medullary thyroid carcinoma (MTC) or MEN 2. Neck lump, hoarseness, or swallowing trouble should be reported.
What the warning actually says
The label's boxed warning: semaglutide caused thyroid C-cell tumors (including MTC) in rodents at clinically relevant exposures. Human relevance is undetermined — large human trials haven't shown a clear signal — but the warning stands.
Who cannot take it
- Personal/family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- This is a hard contraindication, not a caution
Symptoms to report
Neck lump or swelling, hoarseness, trouble swallowing, or persistent throat symptoms while on Ozempic — report promptly.
Unproven — the signal is from rodent studies. Human trials haven't confirmed it, but the warning excludes MTC/MEN2 patients as precaution.
If you have no MTC/MEN2 history, the human-evidence gap means the actual risk is unclear — discuss at consultation. The contraindication is absolute only for the two specific conditions.
FDA label — boxed warning; SUSTAIN thyroid safety analysis.