For all steroid cycles that are longer than 7 weeks, it is recommended to use HCG during the cycle. A small dose of HCG will keep the testicles working as normal as HCG mimics LH and the presence of LH triggers the Leydig cells in the testicles to produce testosterone. If HCG is used, it is very easy to recover after a cycle. When HCG is used during the cycle then it shouldn't be used during PCT. It is also not recommended to use too much HCG as it can also desensitize your testicles the same way if you are not using HCG at all. It is very important to use just the right amount to cause the testicles to produce an identical amount of test as they normally would. Because if you use too little then you won't get any effect and if you use too much then desensitization and other side effects like gyno can occur.
Recommended amounts of HCG based on the cycle length:
1-7 week steroid cycle - No HCG
8 week steroid cycle - Week 3-8 250iu twice a week
12 week steroid cycle - Week 3-12 250iu twice a week
16 week steroid cycle - Week 3-8 250iu twice a week
Week 11-16 250iu twice a week
IF HCG was not used during the cycle it can be used in the last weeks of steroid cycle or during PCT this way:
1-7 week steroid cycle - No HCG
8-week steroid cycle - 1000iu's once a week for 2 weeks
12-week steroid cycle - 1000iu's once a week for 3 weeks
16-week steroid cycle - 1000iu's once a week for 3 weeks
I recommend using Aromatase Inhibitor while doing 1000iu injections to keep estrogen in control because the HCG causes much more testosterone to be produced and it lets more testosterone aromatize to estrogen. And also, HCG at this dose causes a small amount of estrogen to be produced.
If you use HCG during a cycle then it is necessary to stop using HCG 2 weeks before steroids leave your system. This allows your testicles to become sensitive to the natural LH signal from the pituitary gland and lets you quickly recover after the steroids and HCG have cleared your system. That is the main reason why it's recommended to use HCG on cycle because it lets you start fast recovery the moment when PCT starts.
If you are not using HCG during the cycle then it's recommended to start it as soon as possible, preferably while still using steroids.
The least effective way to use HCG is after the cycle. Because, when using steroids your testicles stop producing testosterone because the brain doesn't release LH. When this happens, your testicles decrease in size and become desensitized to the LH when brain finally start releasing it. That's the cause why some people never recover after a long AAS cycle even though they use HCG, HMG, SERMS and other drugs. Because if testicles have been shut down for too long, they become permanently desensitised.