Semaglutide labels describe thyroid C-cell tumors in rodent studies. Tirzepatide labels describe thyroid C-cell tumors in rats.

Whether that finding translates to humans hasn't been established the same way. The boxed warning still applies to the label.

The approved product labels contraindicate use in patients with a personal or family history of medullary thyroid carcinoma (a specific kind of thyroid cancer), or with Multiple Endocrine Neoplasia syndrome type 2 (a genetic condition).

Large human studies are broadly reassuring over short-to-moderate follow-up, but labels still treat the rodent C-cell finding as unresolved in humans.