This may interest some on the BB, I just tapped into a web page on hypo
“Within the range of normal for thyroid hormone, there is a rather wide degree of variation from individual to individual. Significant numbers of people are relatively hypometabolic and therefore subclinically hypothyroid in the lower normal ranges of thyroid hormone levels….It is our belief that it is good and acceptable medical practice, when a person has a symptom complex suggestive of thyroid hypofunction, but is shown to have lower normal ranges of thyroid hormone, to do a clinical trial on thyroid hormone maintenance therapy sufficient to increase these lower normal thyroid hormone values to upper normal values.” Something else too, “With thyroid injury by disease or treatment, there is a shift to T3 production with less relative T4 production. Conversely, various disease states may alter the peripheral deiodination of T4 to form T3 in peripheral tissues, decreasing the totality of thyroid hormone effect. These variations in the ratios of T3 and T4 are sufficiently frequent and of a magnitude that we prefer to measure both in evaluating thyroid function.” Also, “The TSH measurement is also a fundamental importance…it reflects the sufficiency of central nervous supply of thyroid hormone (T3), A normal range TSH indicates that the hypothalamus senses a normal range of thyroid hormone and is stimulating the thyroid to continue making and releasing thyroid hormone at the same rate. An elevated TSH signals central nervous system insufficiency… a reduced TSH indicates that the CNS senses EITHER increased amounts of thyroid hormone OR exactly the amount that turns off this signaling mechanism.” Hope you find this interesting and helpful, but maybe everyone knew all this already.