As athletes, we are most concerned with the "PT" part of the HPTA. "P" being the pituitary and "T" being the Testes. To review, our hormonal responses are based mainly on negative feedback. For example, supragenetic levels of Testosterone or any AAS will signal the pituitary to stop secreting LH and will signal the hypothalamus to stop secreting gonadotropin-releasing hormone (GRH). So, during an AAS cycle, we experience low, natural Testos levels, a reduction in testuclar mass, low LH, and low GRH. The goal of PCT (recovery) is to get the HPTA back to normal.
The correct name/acronym for gonadotropin-releasing hormone is actually GnRH
The most important aspect of recovery is getting testicular mass back to normal as quickly as possible. There is only one drug that will do this and do it quickly--HCG. HCG imitates LH (which is suppressed).
This not correct. HMG or Human Menopasual Gonadotrophin will increase testicle mass, and it will do it every bit and as good as HCG if not better. HMG contains LH (signal lydig cells to start T production in the testicles) and FSH (which will signal the sertioli cells to start sperm production). It is a known medical fact that using high doses of exogenous T and other AAS will shut down sperm production, so restarting sperm production will also help increase the size and volume of the testicles
Also if you happen to have connections in the world of reproductinve endocrinology, you can get rLH and rFSH to use for testicle rehab as well, and a combination of these recombinant gonadotrophins will do every bit as good as HCG. Granted these drugs are more expensive and not as readily avaiable as HCG, they will still increase the mass and/or volume of the male testicle
HCG acts independently of the HPTA suppression and independent of the meds from the AAS cycle. In this situation, the only side effect we need to worry about is the return of estrogen to normal levels (estrogen rebound). Since estrogen is already at very low levels (the athlete used an aromatase inhibitor during his AAS cycle), Nolvadex is sufficient to block the onrush. By the time the athlete is using nolvadex-only, his testes are up to their normal size. And the pituitary begins to release its own LH.