Well that's because Formex isn't pure formestane, it's converted into an anabolic steroid (more than just regular formestane)! That's why it was pulled off the market. It was REALLY good for that reason, but is also suppressive so use with caution! Regular formestane is good stuff for PCT, on cycle, or by itself, though it does convert as a steroidal AI, to 4-hydroxy-test IIRC.
Some will say that the conversion to 4-hydroxy-test is suppressive, but for the amounts used on-cycle or in PCT I don't think it should be a real concern. Lots of people recover quite nicely using it in PCT.
I like formastane's effects, and 6-bromo high dosed, run by themselves.