Just been speaking on the thyroid at ACNEM last week and am finding that practitioners across the board are getting more and more curly thyroid cases.  One scenario that we increasingly see is something that might be described as ‘T3 resistance’, when your patient’s T3 value looks healthy but they continue to manifest the signs and symptoms of hypothyroidism.  There are several differentials to consider of course , including the good old elevated rT3 (which ideally should be < 100 times your patient’s actual T3 value – so that means if they have a T3 of 4 you want an rT3 of <400).  The other big one to consider is interference from peripheral goitrogens e.g. carnitine.  But before we get more fancy and consider radical treatment options such as T3 treatment, which is increasingly being used, don’t forget that deficiencies of iron, zinc and vitamin A all individually impair either binding of T3 to its receptor or activity of the receptor itself.  So remember that a simple little deficiency of one of these nutrients on the side might just be the key to the so called T3 resistance in your clients 🙂