I'm not an expert. I'm only copy pasting some of an article I read to try and contribute to the conversation to get a better understanding myself. So here goes...
"It is important that low-dose hCG is started before testicular sensitivity is reduced, which appears to rapidly manifest within the first 2-3 weeks of steroid use. Also, it’s important to discontinue the hCG before you start PCT so your leydig cells are given a chance to re-sensitize to your body’s own LH production. A more convenient alternative to the above recommendation would be a twice a week shot of 200iu hCG, or possibly a once a week shot of 500iu. However, it is most desirable to adhere to a lower more frequent dose of hCG to mimic the body’s natural LH release and minimize estrogen conversion. Overview
For preservation of testicular sensitivity, use 100iu hCG ED starting 7 days after your first AAS dose. At the end of the cycle, drop the hCG two weeks before the AAS clear the system. For example, you would drop hCG about the same time as your last Testosterone Enanthate shot. Or, if you are ending the cycle with orals, you would drop the hCG about 10 days before your last oral dose. This will allow for a sudden and even clearance in hormone levels, while initiating LH and FSH production from the pituitary, to begin stimulating your testes to produce testosterone. Remember, recovery doesn’t begin until you are off hCG since your body will not release its own LH until the hCG has cleared the system."
