Xenadrine/Ephedrine and thyroid function

[Tempest]

I have heard from a friend that prolonged Xenadrine/Ephedrine can seriously mess up your thyroid function such as when you quit and try to lose weight normally, you can't. He also told me that if you take it for too long (say, a year) than even if you quit for another year and want to go back for, say a crash 3 week program, it does nothing, fat-loss-wise.

Any of the above true?

[BLADE]

If you take it long enough your suppressed immune system gets hit and your sick.

I try to use it when I really need it ( like yesterdays interview after little sleep I took half an ephedrine, did not want to come across nervous )

But you have to get some real rest so try not to go back to back days.