Novo Nordisk has warned patients about the risk of thyroid C-cell tumors associated with the use of Ozempic or Wegovy. In the prescribing information, the manufacturer noted that semaglutide caused “dose-dependent and treatment-duration-dependent thyroid C-cell tumors” in rodents, but its impact on human cancer remains undetermined.

The U.S. Food and Drug Administration (FDA) has advised people with a family history of thyroid cancer against (pdf) taking Wegovy.