Millions of people take thyroid medications like Synthroid®, Levoxyl®, or levothyroxine. These are all forms of the T4 thyroid hormone, i.e., a thyroid hormone molecule containing 4 iodine molecules. Maintaining normal thyroid hormone levels are important for control over metabolic rate and weight control, energy, mood, cholesterol, and many other aspects of health.  

But I ask them: "Do you feel normal?"

7 times out of 10, they will say something like, "No, I don't feel normal. I'm...