Abstract Background: Reverse T3 (rT3) is a biologically inactive form of that created by peripheral 5 deiodination T4 type 1 and 3 deiodinases may block binding to the thyroid hormone receptor. As about 15% patients on L-T4 replacement with normalized TSH report continued fatigue other hypothyroid symptoms, efforts are needed understand why this occurs how it can be corrected. Decades ago, endo...
