T4 within the lab range does not mean you are healthy

I was diagnosed with an underactive thyroid in 2003, and like every other good patient, I had my labs done every 6 months. The labs the doctor requested were usually TSH and T4. 

The result was usually “every looks fine, your labs are normal”, and every now and then the doctor might do a slight adjustment of my T4 thyroid hormone medication upwards or downwards.

The labs showed my results were “normal”. But I wasn’t feeling “normal”.

So what could have been the problem?

Knowing what I know now, what I have learned over the years, is that T4 is not the actual hormone that your body uses for metabolism, energy and all those wonderful things. The T4 hormone is like a “storage” hormone.

And just because you have enough in the warehouse, doesn’t mean it actually makes it out of the warehouse and gets to work.

As Paul Robinson wrote in his book [1]: “T4 is sometimes referred as a storage hormone, because, if working correctly, it should provide a reservoir of thyroid hormone for future use within the body… So T4 is barely a hormone at all. T4 is a pro-hormone and only important in that it may be converted to T3, our biologically active thyroid hormone.”

So you can more then enough T4 hormones, but if your body is not converting it to T3, you will experience hypothyroid symptoms.

You can have enough T4 hormones, but if your T3 hormones are not getting into the cells, you will experience hypothyroid symptoms.

What you can do

Next time when you have your labs done, and your doctor only ticks TSH and T4 on the lab form, you should do the following: ask the doctor to test for T3 and thyroid antibodies.

If your doctor refuses, I am sorry to say, but your doctor is not the right doctor to help you with your hypothyroid symptoms. It is time to find another doctor who knows and understands the complexity of hypothyroidism.


(1) Recovering With T3, p30. Paul Robinson

Adele du Rand

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