The thyroid is called the master regulator of the body is it is important to have normal t3 levels in order to maintain proper function. The thyroid is located in the neck, below the adams apple in men and above the junction of the clavicles. In some people it may extend a little below the neck and into the ribcage, but this is rare. The thyroid produces thyroid hormone and secretes it throughout the blood stream. In the initial stage, the thyroid hormone is called T4. This is because there are 4 different binding sites for iodine on the thyroid hormone. T4 has all of the sites bound.
As the hormone circulates throughout the body, some of the hormone become de iodinated and only have 3 iodines attached to it. This version of thyroid hormone is called T3. It is actually much more active than T4. Thyroid t3 levels are very important to regulate because the hormone is so active. Normal t4 and t3 levels can be measured in the blood. The actual amounts are difficult to figure out because of the concentrations and the different medical opinions that exist.
The National Academy for Clinical Biochemistry (NACB) believes in certain guidelines for the free T3. They have published a consensus statement that state that the normal range for Free T3 should be 3.5-7.7 pmol/L (0.2 – 0.5 ng/dL). This was produced in 2002. Other sources, such as the Family Practice Notebook, the normal reference range for Free T3 of 230 – 619 pg/dL. This is (0.23 – 0.619 ng/dL). This is an incredibly small amount of the hormone. A nanogram is one billionth of a gram. A picogram and a trillionth of a gram. These very small amounts of T3 can have a very large affect on the functions of the body.
One of the reasons why there is some confusion about the thyroid hormone levels is that some of the hormone is bound while some of it is free. In general, almost all of the hormone is bound in the blood to thyroid hormone binding globulin. This special protein transports the T3 all over the body since it is not very soluble in the blood without it. That is why a lot of tests also include bound T3 and measurements of thyroid hormone binding globulin.
The thyroid can either be too high, too low, or just right. In a lot of cases people just get the hormone tested routinely when they are feeling tired. They may have a slightly low lever and start on slight amounts of supplementation. This may be overtreatment since not that many people have low thyroids and there is a penchant in medicine to treat the number, not the patient. That is why you should always have a good evaluation of the thyroid before starting on any medicines. So be sure you truly understand abnormal and normal T3 levels before changing any medicines.