The Very Important Thyroid Gland
TSH is secreted by the pituitary in the brain, telling the thyroid to secrete T4, which is not the active thyroid hormone. T4 must then be converted in the body to the active thyroid hormone T3. When T4 and T3 levels drop, the TSH should increase indicating hypothyroidism. This is the standard way to diagnose hypothyroidism. There are, however, many things that result in the same symptoms of hypothyroidism but are not diagnosed using the standard levels for TSH, T4 and T3 testing.
First of all, there can be pituitary dysfunction that results in low normal TSH levels along with low normal T4 and T3 levels. Second, many patients do not adequately convert T4 to the active T3, resulting in low levels of active thyroid hormone despite having a normal TSH. Lastly, there is another problem that can occur at the level of the thyroid receptor. These patients experience some “resistance” at the thyroid receptors and may need higher levels of active hormone to create normal functioning.
The combination of factors results in many patients having inadequate thyroid effect. Restoring your free T3 hormone to optimal levels can create an improvement in maintaining a normal metabolism, body temperature and energy level. Benefits of optimizing thyroid hormones may include increase in energy, decrease in insulin resistance, weight loss, decrease in hair loss for women and improvement in body temperature. Studies have shown a potential increase in heart disease and LDL levels in “sublinical hypothyroidism.” Thyroid hormone has also been shown to improve symptoms of depression in studies when it was added to an anti-depressant.