The fundamental problem in all of the guidelines for hypothyroidism is the ignoring or dismissing of the post thyroid functions of peripheral metabolism and peripheral hormone reception.  These functions were discovered circa 1970 and have become quite established in medical science literature since.  Since these functions are substantially in series between the thyroid and the body's symptom producing cells, their deficiencies mimic deficient secretion by the thyroid gland (hypothyroidism).

Unfortunately, there are two definitions of hypothyroidism, "the clinical consequences of inadequate secretion by the thyroid gland,"  above, and "the clinical consequences of inadequate thyroid hormones in the body."  While the former only implicates the thyroid gland, the latter implicates all of functions that can cause deficient hormones in the body, including the ignored and/or dismissed post thyroid functions.

This would not be a problem if the definition of "hypothyroidism" were stipulated and logical consistency maintained.  Unfortunately, one or both of these problems compound the lack of recognition of the post thyroid functions and potential deficiencies.  The recent guideline/guidance by the Royal College of Physicians becomes logically inconsistant with its stated limitation of primary hypothyroidism as it excludes any further therapy for the symptoms of hypothyroidism that exist with a "normal" TSH.  The American Association of Clinical Endocrinologists employ diagnostics for the thyroid gland but also proscribe therapies suitable for the post thyroid deficiencies.

Unfortunately there are not checks and balances against these discrepancies.....