What do T4 and Free T4 do?
Your thyroid produces T4 (Thyroxine), but it can become Free T4 or as referred to on a blood test FT4 when the T4 hormone is not attached or bonded to a protein in your blood or a receptor.
The form that is bound or known as T4, is inactive and accounts for 98% of our T4 hormone. Free T4 is the active form of thyroxine accounting for the other 2% but is very powerful.
If you are unfamiliar with what your T4 functions are or how to make it work better in the process, you can learn more here. Although I can not test the various hormones on a hair analysis test, I can see if the complete process is working adequately. If you would like to start at the beginning of how your T4 is stimulated to be produced you can start from the beginning here. We are going to zoom in on the finer details once T4 is made in this article.
Why do I need a Free T4 test?
The Free T4 test is a more accurate reflection of thyroid hormone function and may be done in place of the Total T4 test. The Free T4 test is commonly done in the United States on newborns, soon after birth to check for Congenital hypothyroidism. This condition occurs when a baby is born with a thyroid gland that is not located where it should be, missing completely or an under-active thyroid gland.
Testing your Free T4 is important if you have symptoms of thyroid disease, you have an abnormal TSH test, an enlarged thyroid (goiter), or when you have a thyroid. Adequate amounts of Free T4 are important as it communicates to the thyroid gland as a biofeedback mechanism if it is producing enough TSH and T4 or not. The normal adult range for Free T4 in adults is 0.8 to 1.8 nanograms per deciliter (ng/dL). Levels outside of these ranges are red flags that something may be going on within the thyroid functions.
What could the Free T4 and TSH levels mean?
If you have an elevated Free T4 and a low TSH, it could indicate hyperthyroidism (fast) which is an overactive thyroid or hyperactive thyroid. Conditions associated with hyperthyroidism would be Graves disease or an autoimmune disease. There can be some dangers associated with a high Free T4 level including an increased risk of heart disease by 87% and double the risk of a fatal heart attack.
Abnormally low Free T4 levels and a high TSH may signal hypothyroidism. This means your thyroid is not making enough hormones. An underlying condition, such as Hashimoto’s disease, another autoimmune disorder, could be the cause of an under-active thyroid.
Free T4 affects your thyroid in controlling metabolism or oxidation, mood, energy, hair health, and gut functions so it is very important to look at a deeper picture of how all of the forms of thyroid hormone are working, not just the T4 or TSH.
In upcoming blogs, I will explain the other pieces to your overall thyroid health and the hormone roles of Reverse T4, T3, Reverse T3, Free T3, and antibody tests.
If you have any concerns or would like assistance,
LET’S CHAT about your health goals!
To learn more about T3 go HERE.
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