Depends on how harsh your cycle is man. E.g. some people use OTC with mild PH like H-Drol.
I did 6 weeks H-Drol 50mg 1st week 75mg the rest, my first cycle, and I did not feel shut down at all. My PCT was:-
Nolva - 20/20/10/10
TCF- 1 - dosed according to bottle
PCT Assist - 0/0/6/6/6/6
Lean Xtreme - 0/3/3/3/3
And all other usual support supps (e.g. creatine, Jack3d etc....)
I know people say that they feel they recover faster with SERM, opposed to OTC.