Large Study Finds No Increased Thyroid Cancer Risk with Long-Term GLP-1 Drug Use
In nearly 90,000 patients followed for a median of 4.5 years, long-term GLP-1 receptor agonist use was not associated with increased thyroid cancer risk.
Quick Facts
What This Study Found
No increased thyroid cancer risk was found in 89,646 GLP-1 RA users followed for a median of 4.5 years compared to matched controls on other diabetes drugs.
Key Numbers
N=89,646; median follow-up 4.5 +/- 2.3 years; no increased thyroid cancer risk vs insulin, metformin, SGLT2i, DPP-4i, sulfonylureas, or thiazolidinediones.
How They Did This
Propensity score matched cohort study using TriNetX electronic health records (2014-2020) with active comparator controls.
Why This Research Matters
This is one of the largest and longest studies to address the thyroid cancer concern, providing meaningful safety reassurance for millions of GLP-1 users.
The Bigger Picture
This large-scale evidence should help resolve lingering fears about thyroid cancer that have affected both prescribing decisions and patient acceptance.
What This Study Doesn't Tell Us
Observational design — cannot fully exclude residual confounding. Electronic health records may have coding inconsistencies.
Questions This Raises
- ?Does the safety signal hold for newer GLP-1 drugs not included in this period?
- ?Are specific GLP-1 agents safer than others regarding thyroid risk?
Trust & Context
- Key Stat:
- 89,646 patients Large propensity-matched cohort showing no increased thyroid cancer risk with GLP-1 RA use
- Evidence Grade:
- Large propensity-matched cohort with active comparators — strong observational evidence, though not a randomized trial.
- Study Age:
- Published in 2025, providing the most current large-scale thyroid cancer safety data for GLP-1 drugs.
- Original Title:
- Long-Term Glucagon-Like Peptide 1 Receptor Agonist Use Is Not Associated With Increased Risk of Thyroid Cancer in Adults With Type 2 Diabetes.
- Published In:
- Diabetes/metabolism research and reviews, 41(8), e70104 (2025)
- Authors:
- Pollack, Rena, Stokar, Joshua
- Database ID:
- RPEP-13075
Evidence Hierarchy
Frequently Asked Questions
Do GLP-1 drugs cause thyroid cancer?
This large study of nearly 90,000 patients found no increased thyroid cancer risk with long-term use, providing substantial reassurance.
Why was there concern about thyroid cancer and GLP-1 drugs?
Early animal studies showed thyroid tumors in rodents, but human data including this large study have not confirmed that risk in people.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-13075APA
Pollack, Rena; Stokar, Joshua. (2025). Long-Term Glucagon-Like Peptide 1 Receptor Agonist Use Is Not Associated With Increased Risk of Thyroid Cancer in Adults With Type 2 Diabetes.. Diabetes/metabolism research and reviews, 41(8), e70104. https://doi.org/10.1002/dmrr.70104
MLA
Pollack, Rena, et al. "Long-Term Glucagon-Like Peptide 1 Receptor Agonist Use Is Not Associated With Increased Risk of Thyroid Cancer in Adults With Type 2 Diabetes.." Diabetes/metabolism research and reviews, 2025. https://doi.org/10.1002/dmrr.70104
RethinkPeptides
RethinkPeptides Research Database. "Long-Term Glucagon-Like Peptide 1 Receptor Agonist Use Is No..." RPEP-13075. Retrieved from https://rethinkpeptides.com/research/pollack-2025-longterm-glucagonlike-peptide-1
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.