This whole T4 thing is rediculous.
I have kept my mouth shut on it but it is amazing how people can follow advice just blindly thrown out there by a "guru". This isn't a flame to the original poster or the "guru" as I have seen this same ? posted at least 100 times across the boards. And gotten at least 10 PM's about the use of T-4 and GH.
Your body has to convert it, and the conversion is based on many things, certain supplements interfere with it's conversion as well.
Trust me I have 3 hyper thyroid females in my family and seen the absolute hell they went through when treated with T4. Only when T3 was introduced did their lives resume.
There is a ton of literature out there on this as well and many expert endos know you must use T3 as well as some use Armour thyroid and the synthetic Thyrolar T4/T3. Many euthyroid people (complete thyroidectomy) have trouble with gold standards of treatment T4 as the thyroid is gone and there are a multitude of other things like T-1 and T2 that aren't in the synthetic formulations.
T4 isn't very stable and there have been dosing problems with generics and off brands. (FDA) documented, plus there are stability and storage problems that can affect potency as well.
Read up a bit if you guys are into science
http://www.altsupportthyroid.org/t3/t3medrefs2.php
But I have seen it first hand lab tests doses and the havoc it causes. USE T3. simple potent easy to control and you know what youre getting for the most part dose wise.