From each FDA label

Do GLP-1s cause thyroid cancer?

9 of the 10 current GLP-1 labels carry a warning on thyroid tumors. Wegovy's label says: "In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures." "It is unknown whether Wegovy causes thyroid C-cell tumors, including MTC, in humans, as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined."

Read from each manufacturer's FDA label on DailyMed. The newest revision saying anything on this is Aug 28, 2026.

Word for word

What each label says about thyroid tumors

Sentences from each label's warnings and side effect sections. Only cross-references are removed.

Wegovy · Warning: Risk of Thyroid C-Cell Tumors

  • In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures.
  • It is unknown whether Wegovy causes thyroid C-cell tumors, including MTC, in humans, as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.
  • Cases of MTC in patients treated with liraglutide, another GLP-1 receptor agonist, have been reported in the postmarketing period; the data in these reports are insufficient to establish or exclude a causal relationship between MTC and GLP-1 receptor agonist use in humans.

Label revised Jun 18, 2026. DailyMed

Ozempic · Warning: Risk of Thyroid C-Cell Tumors

  • In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures.
  • It is unknown whether Ozempic causes thyroid C-cell tumors, including MTC, in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.
  • Cases of MTC in patients treated with liraglutide, another GLP-1 receptor agonist, have been reported in the postmarketing period; the data in these reports are insufficient to establish or exclude a causal relationship between MTC and GLP-1 receptor agonist use in humans.

Label revised Jun 1, 2026. DailyMed

Rybelsus and Ozempic tablets · Warning: Risk of Thyroid C-Cell Tumors

  • In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures.
  • It is unknown whether Rybelsus and Ozempic tablets cause thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.
  • Cases of MTC in patients treated with liraglutide, another GLP-1 receptor agonist, have been reported in the postmarketing period; the data in these reports are insufficient to establish or exclude a causal relationship between MTC and GLP-1 receptor agonist use in humans.

Label revised Jan 30, 2026. DailyMed

Zepbound · Warning: Risk of Thyroid C-Cell Tumors

  • In rats, tirzepatide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) in a 2-year study at clinically relevant plasma exposures.
  • It is unknown whether Zepbound causes thyroid C-cell tumors, including MTC, in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined.
  • Zepbound is contraindicated in patients with a personal or family history of MTC or in patients with MEN 2.

Label revised Aug 28, 2026. DailyMed

Mounjaro · Warning: Risk of Thyroid C-Cell Tumors

  • In both sexes of rats, tirzepatide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) in a 2-year study at clinically relevant plasma exposures.
  • It is unknown whether Mounjaro causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined.
  • Mounjaro is contraindicated in patients with a personal or family history of MTC or in patients with MEN 2.

Label revised Aug 27, 2026. DailyMed

Foundayo · Warning: Risk of Thyroid C-Cell Tumors

  • In products with GLP-1 receptor agonist activity that are pharmacologically active in rats and mice, rodent thyroid C-cell tumors (adenomas and carcinomas) have been observed at clinically relevant exposures and are considered GLP-1 receptor-dependent effects in rodents.
  • Orforglipron is not pharmacologically active in rats or mice and did not produce tumors in rodents.
  • While orforglipron is pharmacologically active at the human GLP-1 receptor, the human relevance of GLP-1 receptor-dependent thyroid C-cell tumors observed in rodents has not been determined.

Label revised Jul 29, 2026. DailyMed

Trulicity · Warning: Risk of Thyroid C-cell Tumors

  • In male and female rats, dulaglutide causes a dose-related and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure.
  • Glucagon-like peptide-1 (GLP-1) receptor agonists have induced thyroid C-cell adenomas and carcinomas in mice and rats at clinically relevant exposures.
  • It is unknown whether Trulicity will cause thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans, as the human relevance of dulaglutide-induced rodent thyroid C-cell tumors has not been determined.

Label revised Jun 16, 2026. DailyMed

Saxenda · Warning: Risk of Thyroid C-cell Tumors

  • Liraglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and/or carcinomas) at clinically relevant exposures in both genders of rats and mice.
  • Malignant thyroid C-cell carcinomas were detected in rats and mice.
  • It is unknown whether Saxenda will cause thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans, as the human relevance of liraglutide-induced rodent thyroid C-cell tumors has not been determined.

Label revised Feb 25, 2026. DailyMed

Victoza · Warning: Risk of Thyroid C-cell Tumors

  • Liraglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and/or carcinomas) at clinically relevant exposures in both genders of rats and mice.
  • Malignant thyroid C-cell carcinomas were detected in rats and mice.
  • It is unknown whether Victoza will cause thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans, as the human relevance of liraglutide-induced rodent thyroid C-cell tumors has not been determined.

Label revised Oct 14, 2025. DailyMed

Byetta: no finding on this in the sections read here.

Not from trials

Reports to FDA about thyroid tumors

Counts of voluntary reports from patients and doctors. They cannot show that a medicine caused anything and cannot give a rate, and a brand used by more people draws more reports.

MedicineReports namingAll reports on it
ByettaThyroid cancer: 240 · Thyroid neoplasm: 50 · Medullary thyroid cancer: 2152,087
VictozaThyroid cancer: 124 · Thyroid neoplasm: 79 · Medullary thyroid cancer: 4041,462
TrulicityThyroid cancer: 91 · Thyroid neoplasm: 29 · Medullary thyroid cancer: 2087,279
MounjaroThyroid cancer: 78 · Medullary thyroid cancer: 26 · Thyroid neoplasm: 1697,440
OzempicThyroid cancer: 74 · Medullary thyroid cancer: 59 · Thyroid neoplasm: 2270,863
SaxendaThyroid cancer: 34 · Thyroid neoplasm: 5 · Medullary thyroid cancer: 37,270
ZepboundThyroid cancer: 27 · Medullary thyroid cancer: 880,835
WegovyThyroid cancer: 1925,993
Rybelsus and Ozempic tabletsThyroid cancer: 12 · Thyroid neoplasm: 6 · Medullary thyroid cancer: 57,758

Counted through openFDA from FDA's Adverse Event Reporting System, refreshed weekly. One report can name several terms.

Updated automatically

Latest FDA label updates

Written from each source's own record as it changes. Every change on GLPcompare

Questions

Thyroid cancer on a GLP-1: common questions

Does Wegovy cause thyroid cancer?

Its FDA label: In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures. It is unknown whether Wegovy causes thyroid C-cell tumors, including MTC, in humans, as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.

Does Ozempic cause thyroid cancer?

Its FDA label: In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures. It is unknown whether Ozempic causes thyroid C-cell tumors, including MTC, in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.

Does Rybelsus cause thyroid cancer?

Its FDA label: In mice and rats, semaglutide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure at clinically relevant plasma exposures. It is unknown whether Rybelsus and Ozempic tablets cause thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined.

Does Zepbound cause thyroid cancer?

Its FDA label: In rats, tirzepatide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) in a 2-year study at clinically relevant plasma exposures. It is unknown whether Zepbound causes thyroid C-cell tumors, including MTC, in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined.

Does Mounjaro cause thyroid cancer?

Its FDA label: In both sexes of rats, tirzepatide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) in a 2-year study at clinically relevant plasma exposures. It is unknown whether Mounjaro causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined.

Does Foundayo cause thyroid cancer?

Its FDA label: In products with GLP-1 receptor agonist activity that are pharmacologically active in rats and mice, rodent thyroid C-cell tumors (adenomas and carcinomas) have been observed at clinically relevant exposures and are considered GLP-1 receptor-dependent effects in rodents. Orforglipron is not pharmacologically active in rats or mice and did not produce tumors in rodents.

Does Trulicity cause thyroid cancer?

Its FDA label: In male and female rats, dulaglutide causes a dose-related and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure. Glucagon-like peptide-1 (GLP-1) receptor agonists have induced thyroid C-cell adenomas and carcinomas in mice and rats at clinically relevant exposures.

Does Saxenda cause thyroid cancer?

Its FDA label: Liraglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and/or carcinomas) at clinically relevant exposures in both genders of rats and mice. Malignant thyroid C-cell carcinomas were detected in rats and mice.

Does Victoza cause thyroid cancer?

Its FDA label: Liraglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and/or carcinomas) at clinically relevant exposures in both genders of rats and mice. Malignant thyroid C-cell carcinomas were detected in rats and mice.

Other side effects

Trial rates describe groups, not what one person will feel. Talk to your clinician before starting, stopping or changing a medicine.

GLPcompare is an informational data platform, not a medical provider or pharmacy. Nothing here is medical advice, a diagnosis, or a recommendation to start, stop, or change any treatment. Data is aggregated from public sources and can be incomplete or out of date. Always confirm with a licensed clinician and the current FDA label.