Focus on the Thyroid
While the focus is primarily on TSH, T4, T3, fT4, Ft3, rT3, TPO & TAA Antibodies blood test markers. There are other factors that can cause "Low Thyroid" symptoms. Thyroid advocates and support groups treat the thyroid like it is the only organ in the body. In Chapter Four of Dr. Kharrazian's best selling thyroid book "Why Do I Still Have Thyroid Symptoms? When My Lab Tests are Normal", six different patterns of low thyroid function, only one of which is treatable with thyroid replacement medication or iodine/selenium supplementation. This is because most people with "symptoms" of low thyroid have functional hypothyroidism due to other dysfunctional organ(s) or microbial infestation and not an actual "thyroid" disease.
While writing this post, a review of Thyroid / Hashimoto social media sites including Dr. Wentz and Mary Shamon revealed no mention of the five none-thyroid patterns in Dr. Kharrazian's book. Not only were the five none-thyroid patterns never mentioned. All health conditions were attributed back to the thyroid. It was if they needed to fix the problem with everything but the kitchen sink.
Thyroid Hormones Pass Through Blood - Brain -Barrier
Thyroid hormones and neuroendocrine transmitters have important influences upon the hypothalamus, and to do so they must pass through the blood–brain barrier. The hypothalamus is bounded in part by specialized brain regions that lack an effective blood–brain barrier; the capillaries at these sites has perforations to allow free passage of hormones and even large proteins and other molecules. At these sites, the brain samples the hormone composition of the blood. Some of these sites are the sites of neurosecretion, where signals are sent from the nerve cells of the hypothalamus to the posterior pituitary. The hypothalamus secretes substances known as neurohormones that start and stop the secretion of anterior pituitary hormones.
Some other aspect of their health is breaking down and producing "low thyroid symptoms". For instance, insulin resistance associated with "Thyroid Overconversion" produced symptoms of fatigue, weight gain, thinning of hair and scalp. You are allowed to have more than one organ dysfunctioning at the same time. It is called Multiple Organ Dysfunction Syndrome.
The focus is typically on on thyroid markers on Social Media groups and the Medical Community. It is as if the only organ in the body is the thyroid. The primary focus is on "Low Thyroid", while Hashimoto's is the most common cause of hypothyroidism. The fact that there are six other factors that cause "Low Thyroid Function". Only one of which is successfully supported, if at all, with thyroid replacement hormone medication or iodine supplementation.
This is because most people with symptoms of hypothyroidism have "functional hypothyroidism" and NOT an actual thyroid disease. Some aspect of their health is breaking down and producing the ubiquitous hypothyroid symptoms. Having "Hypothyroid Symptoms" does not automatically make it a thyroid problem. The "Hypothyroid Symptoms" do not warrant lifelong medication or iodine supplementation. It's all a matter of learning how to look at the entire body, knowing there are other factors that cause "Low Thyroid Symptoms".
The production of thyroxine (T4) and triiodothyronine (T3) is regulated by thyroid-stimulating hormone (TSH), released by the anterior pituitary. The thyroid and thyrotropes (cells in the anterior pituitary) form a negative feedback loop: TSH production is suppressed when the T4 levels are high, and vice versa. The TSH production itself is modulated by thyrotropin-releasing hormone (TRH), which is produced by the hypothalamus and secreted at an increased rate in situations such as cold (in which an accelerated metabolism would generate more heat). TSH production is blunted by somatostatin (SRIH), rising levels of glucocorticoids (cortosol) and sex hormones (estrogen and testosterone), and excessively high blood iodide concentration.