The only thing I've heard about on cycle AI's, is from PED podcasts and injectables. IIRC, It is used to keep as much free Test as possible, available, during the cycle. But that's with moderate/high dose injectable Test - probably doesn't apply to DS/PH's ? My mentor told me to have it handy, but unless you get estro sides, let your body do the regulating on cycle. I also only have experience with 1 & 4-DHEA. I started my AI day one of a 6 week PCT, and ran it 2 weeks past the Clomid (Total - 8 weeks).