If that were true everyone would have thyroid dysfunction lol.
There are a number of scientific studies around that show some effect of radiation such as produced by cell phones. Following is a link to one of those.
https://www.sciencedirect.com/science/article/pii/S0378427405000925?via%3Dihub
From the study that was done with rats used as surrogates for humans, it was concluded: "These results indicate that 900 MHz EMF emitted by cellular telephones decrease serum TSH and T3–T4 levels." The Abstract available did not provide actual data showing the specific effect. I tried to locate the full article, but was unsuccessful. If you find anything more specific, please let us know.
It should also be pointed out that the output varies among phones, and also that the location of the phone, length of time is usage, and its proximity to y9our body also has an effect. So is any of this going to keep people from their beloved cell phones? Extremely doubtful.