The relationship has yet to be established. Some studies show a statistically significant increase in the risk of thyroid cancers - about a 58% increase - when taking GLP-1s for a long period of time. [1] That said the lifetime risk of thyroid cancer is 1.8% for women and 0.6% for men. [2] This would take you up to 2.8% for women and 0.95% for men. However thyroid cancer is extremely treatable, and when localized, has a 99.9% 5-year survival.
Note also that the causal relationship here may be weak or non-existent. Other research shows that it is less likely to cause thyroid cancer than taking insulin, and most treatments for type II are correlated with thyroid cancer risk. [3]
The health risks of obesity absolutely dwarf the hypothetical increase in thyroid cancers. Obesity is itself a risk factor for basically all cancers including thyroid. Frankly, even if there was a 100% chance of thyroid cancer due to GLP-1 usage, that would still be a massive win for population health.
Note also that the causal relationship here may be weak or non-existent. Other research shows that it is less likely to cause thyroid cancer than taking insulin, and most treatments for type II are correlated with thyroid cancer risk. [3]
The health risks of obesity absolutely dwarf the hypothetical increase in thyroid cancers. Obesity is itself a risk factor for basically all cancers including thyroid. Frankly, even if there was a 100% chance of thyroid cancer due to GLP-1 usage, that would still be a massive win for population health.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563602/
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9473679/
[3] https://www.medscape.com/viewarticle/997713