I've been reading through a lot of logs and experiences about people not recovering properly despite what they consider to be a proper PCT. There is one area of concern I feel is keeping a lot of people from having healthy HPTA axis function, and I think it all comes down to timing. I see so many people thinking two weeks after, for example, a testosterone enanthate cycle is long enough to wait. The actual timing has everything to do with ester half-life, cycle length, dosage (how much each injection contains of the drug in mg) and dosing protocol (EOD, ED, M/F, E3D, etc) as these four factors work together to define actual blood serum levels of the drug. Remember, a half-life is the length of time that a drug takes to be expelled by the body such that 50% of said drug remains in the system. When you start your PCT, you want to ensure almost all the drug is out of your system so that it isn't acting against your PCT. Here is a calculator that determines exactly how much of the drug remains in your system based on these factors.

http://pct.befit4free.net/index.php