Enough T4 is not a guarantee for good health

The thyroid gland produces mainly T4 thyroid hormones and a little T3 hormones.  But these two types of hormones play very different roles in your body.

First, T4 has very little biological action of any significance, according to Paul Robinson, author of the book Recovering with T3.  

T4 is more of a storage hormone, or as Robinson states, a pro-hormone.  T4 can be converted into T3 as and when the body needs more T3 hormones.  

However, many biological processes can inhibit or interfere with this conversion process, preventing the T3 from getting into the cells to do its job.  

The essence is this: without T3 in your cells, you can experience hypothyroid symptoms, regardless of what level your T4 hormones are. 

We should not be worried about T4.  We should be focused on T3 – is the T4 converting into T3, and once converted, is the T3 getting into the cells and doing what it supposed to do.