t-3 and t-4?

[Only1eagle]

What is the difference?

I know both effect the thyroid. But I read that T-3 is the strong of the two in the body. So if they do the same thing why would you use one over the other?

 

[dmessina7]

t4 is made by the thyroid directly and converted to t3 when there is a need to do so via a feedback mechanism. t3 is the stuff that increases metabolism. t-3 is the stuff you want to be taking.