related to TSH, not that I believe in TSH tests, but it can give a bigger picture;
"So how does all this relate to optimal thyroid function? In the chapter on thyroid hormone physiology, we discussed the enzyme that converts inactive T4 (thyroxine) into active T3 (triiodothyronine). Remember that 93 percent of the hormone produced by the thyroid is inactive T4 until it is activated mainly in the liver by an enzyme. Cortisol directly inhibits this enzyme (5’-deiodinase) which converts inactive T4 into active T3. This in part can lead to low T3 levels. In addition, elevated cortisol will cause thyroid hormone receptor insensitivity meaning that even if T3 levels are adequate, they may not be able to bind normally to receptor sites. Cortisol will also increase the production of reverse T3 which is inactive. Cortisol can also lower the levels of protein that binds to thyroid hormone so it can circulate in a stable structure. Iodine, as you know from a previous chapter, is extremely vital to thyroid health but high levels of cortisol will increase the excretion of Iodide from the kidney. And finally, elevated cortisol will inhibit TSH (thyroid-stimulating hormone) production by disrupting hypothalamic-pituitary feedback leading to suboptimal TSH production in the range of 1.0-1.5. Has your physician adequately assessed your adrenals before treatment? It is very irresponsible for any physician to treat thyroid hormone dysfunction without thoroughly assessing adrenal gland physiology and of course, blood sugar."