Feb 17, 2026
3 min read
A new review finds no evidence that drugs like Ozempic increase people's risk of developing common thyroid cancer.
If you've considered taking GLP-1 drugs like Ozempic, you may be worried about the possibility of thyroid cancer.However, recent studies have shown that this risk may not exist.
Doctors at the Clayman Thyroid Center in Florida reviewed medical records on GLP-1 use and thyroid cancer.They have been unable to find consistent data, especially in humans, indicating a causal relationship between the two.That said, people with a history of rare thyroid cancer should avoid GLP-1 drugs, the researchers say, in keeping with Food and Drug Administration recommendations.
"The best available human evidence does not show that GLP-1 receptor agonists cause common thyroid cancer or even have an effect if you have developed thyroid cancer," they wrote in a white paper published last month.
GLP-1 ug thyroid cancer
GLP-1 has been around for two decades, although in recent years newer drugs such as semaglutide (Ozempic and Wegovy) and tirzepatide (Mounjaro and Zepbound) have become effective as treatments for early-stage obesity.
These drugs are known to often cause gastrointestinal side effects such as nausea, diarrhea, and constipation.But they have also long been a black box warning about the possible risk of thyroid cancer, especially medullary thyroid cancer (MTC).However, the rationale for including this warning was based primarily on GLP-1 studies in rodents.And that prompted scientists to investigate whether the same pattern could be seen in people taking these drugs.
Clayman's researchers analyzed data from clinical trials, adverse event reports, and large real-world patient studies.Overall, they found nothing to suggest that GLP-1 use was associated with a significantly higher rate of thyroid cancer.Other studies have shown that GLP-1 users are more likely to develop cancer (or rare tumors that can cause cancer), but this may be due to something known as detection bias, the researchers say.
People taking GLP-1 drugs are more likely to see their doctors regularly and/or get screened for thyroid cancer, and this higher level of surveillance may detect more cancers than any side effects of the drug.When studies tried to account for this bias, such as looking at diagnosis rates after the start of GLP-1 (before the drug caused new cancers), they found no evidence of a link to thyroid cancer.
"When the disease progresses after the drug is started, the pattern often reflects the discovery of something that's already there," said co-author Rashmi Roy, in a statement from the center.
When to avoid GLP-1 drugs
The team’s findings should alleviate fears from patients and doctors about GLP-1s and thyroid cancer in general, the researchers say. And there’s even a decent chance that MTC isn’t a real risk to be concerned about.
The Kleinman Thyroid Center handles approximately 2,000 thyroid cancer cases annually, making it one of the largest specialty clinics in the world.So far, they haven't noticed any increase in MTC cases, especially since the popularity of these drugs has exploded.
"We did not observe a wave of MTC in GLP-1 users in practice, where thyroid cancer is more common than anywhere else worldwide. This is consistent with what the best research has shown," they wrote.
Still, researchers caution that their experiences are anecdotal.Because MTC is rare, accounting for about 3% of thyroid cancer, larger population studies may be needed to actually detect or disprove the additional risk of GLP-1 use.So, at least for now, researchers continue to advise people with a personal or family history of MTC (or an inherited disease called MEN2) not to take these drugs.
GLP-1, like any drug, has its risks.Fortunately, thyroid cancer is not a serious disease.
