Yea, I do like to throw a few back; you only go around once in this thing we call life!
Ok, no typo this time: Reverse T3 (RT3). I won't go into all the details here. The best Thyroid site on the Internet has it all.
Go here to learn about Reverse T3 and why it's important in understanding Thyroid health: http://www.stopthethyroidmadness.com/reverse-t3/