SP Gonadotropin is used during steroid treatments to prevent testicular atrophy and total inhibition of testosterone secretion.
HCG (Human chorionic gonadotropin) is a hormone found only in the placenta of pregnant women. For women it has no significant role, but for sportsmen it has some very interesting caractristi. It can mimic the luteinizing hormone (HL), secreted by the pituitary gland, and it is the one that gives the signal of testosterone production. Sex hormones act through negative feedback, when they are present in too large quantities (such as androgen and estrogen steroids) sends a signal to the brain to stop the secretion of HL. During long-lasting steroid cycles, if testosterone secretion is too long suppressed, the testes will begin to atrophy until they lose their functionality. By administering a hormone similar to luteinizing, it can restore testicular function and return to normal size.
Because it produces some accumulation of testosterone in the body, it can also have certain anabolic properties but not very significant. This is why it is not used by athletes for this purpose.
HCG is used for medical purposes to induce ovulation or treat ovarian dysfunction in women, or to stimulate testicles that do not produce enough testosterone in men. It is also used to treat testicles that have not descended into the scrotum, children or adolescents. For sports, it has no practical application, but for athletes using anabolic and androgenic steroids is very useful. As I said above, HCG is similar to luteinizing hormone, which stimulates the testes to secrete testosterone. It is especially useful during very long steroid cycles, or when very high doses are used. In such situations, the hypothalamus no longer signals to the testes to produce testosterone, and the phenomenon of testicular atrophy occurs (decreases). HCG will send a synthetic signal, similar to that sent by LH, and so the testes will produce testosterone further, and avoid atrophy to a greater or lesser extent. It does not just help maintain the size and function of the testicles, but it also helps to bring them to normal if they have diminished. Especially when androgen levels are below the limit (due to steroids), which could have unwanted consequences. Restoring normal testosterone production as quickly as possible is crucial to ending a steroid treatment. The price paid if these levels are not restored is the loss of the big part of the gained muscle mass, the main reason being cortisol. Cortisol sends a signal to the muscle, which is opposite to that of testosterone. If the problem of cortisol is not solved (because of very low levels of testosterone) it will rapidly devour the muscle mass obtained during the steroid cycle.