Why a Low TSH Means Your Doctor Lowers Your Dose, And Other Confusing Issues

Many people write to me asking me to please explain "why, when my TSH results show that my thyroid stimulating hormone (TSH) has dropped, does the doctor want to LOWER instead of RAISE my medicine?" Or, "doesn't a high TSH mean I have too much thyroid? And if that's the case, why is the doctor INCREASING my thyroid hormone medicine?" These are confusing issues that people frequently ask about, hoping for an explanation. Let's go through it all to clarify the issue of what high and low TSH really mean.

Also, if you're not already an expert on TSH, here's a basic overview to help you understand this key thyroid concept: Understanding TSH: An Overview

_{Graphic: Mary Shomon}