what to take inbetween eca cycles?

[gbaz_matt]

I just started an ECA Stack and I don't want to do it for more than 6 week cycles... Anyone have ideas of what I can take inbetween that isn't stimulant but still has results? I don't expect the same results but I want to change it up a little to keep my body from from defending against eca(has happened). I also want to give my heart a break... any ideas? blockers anything that works?