Human chorionic gonadotropin is a hormone found only in pregnant women's placenta. Women have no significant role, but for athletes has some very interesting features. This hormone can imitate luteinizing hormone secreted by the pituitary gland being the one who gives the signal of testosterone. Sex hormones through a negative feedback, when present in excessive amounts (such as steroids androgen or estrogen) to send a signal to the brain to stop the secretion of luteinizing hormone.
During steroid cycles that stretch over long periods if own testosterone secretion is suppressed too long, the testicles will begin to atrophy until losing their functionality.The administration of the luteinizing hormone like, you can play testicular function and their return to normal size. This is the main use of HCG.
Because testosterone produces a mouse accumulation in the body can have some anabolic properties but too little. It is therefore not used by athletes for this purpose. But for someone who follows a cycle of steroids is almost essential. To keep gains during steroid cycle is imperative that proper testosterone levels to normal. Without a natural endocrine response can not keep a mass greater than the initial one.