I dont completely understand the difference in test compositions...such as sus, en, cy...I know different one's stay in your system longer, but why would that really matter, wouldent you just assume take a shot once a week opposed to 3 if there was no difference...I notice people use enthanate for mass oriented cycles and sustanon for more cutting cycles, (or at least I think I notice this) can someone give me some explinations, thanks....