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. If the T4 hormone is not attached or bonded to a protein in your blood on a receptor it is now Free T4.
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.
What does T4 thyroid hormone do?
You will want to understand what your T4 hormone functions are and how to make it work better in the process. Although I can not test the various hormones on a Hair Analysis test, I can see if the overall process is working adequately. Learn how to increase your T4 and how it is stimulated to be produced, for greater understanding too. Let’s zoom in on what happens once you have T4 to ensure none is left unbound.
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 common in the United States to test 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. It could also link with an abnormal TSH test or an enlarged thyroid (goiter). Adequate amounts of Free T4 are important as it communicates to the thyroid gland. It is 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) [1]. 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. This means you have a fast overactive thyroid or hyperactive thyroid [2]. Conditions associated with hyperthyroidism would be Graves disease or an autoimmune disease. There can be some dangers with having a high Free T4 level. These include 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 which is 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. It is very important to look at a deeper picture of how all of the forms of thyroid hormone are working. Don’t base the total thyroid health just off of the T4 or TSH.
I explain the other pieces to your thyroid health in the articles on this site. Learn about 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.
[1] https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=free_t4_thyroxine
[2] https://www.endocrineweb.com/thyroid-what-are-t3-t4-tsh
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