Using T4 instead of T3

[doubleguns]

Can anyone help in answering this question for me? On Bodybuilding.com, I found an article on Cytomel stating that T4(Synthroid) might be a possible alt. to using T3 (cytomel). I know that the T4 is much weaker than the T3, but my girlfriend has a thyroid disorder from childhood, and I have ready access to T4. Does anyone have any suggestions on dosages or opinions on using T4. I know using clen is a safer alt. to T3 or T4, but like I said, I have an ample supply of the T4 using scripts from my girl.

Thanks for any help bros,

dg/;