Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryo soon after conception and later by the syncytiotrophoblast (part of the placenta). hCG is extensively used as a parenteral medication in fertility therapy in lieu of luteinizing hormone. In the male, hCG injections are used to stimulate the leydig cells to synthesize testosterone. The intratesticular testosterone is necessary for spermatogenesis from the sertoli cells. Typical indications for hCG in men include hypogonadism and fertility treatment.

hCG sold under brand names including Pregnyl, Follutein, Profasi, and Novarel use chorionic gonadotropins derived form the urine of pregnant women, while Ovidrel is a product of recombinant technology. Novarel and hCG from APP are typically considered generics in the United States.

In the world of performance enhancing drugs, hCG is increasingly used in combination with various Anabolic Androgenic Steroid (AAS) cycles. When AAS are put into a male body, the body's natural negative feedback loops cause the body to shut down its own production of testosterone via shutdown of the HPTA (hypothalamic-pituitary-testicular axis). High levels of AASs that mimic the body's natural testosterone trigger the hypothalamus to shut down its production of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Without GnRH the pituitary gland stops releasing luteinizing hormone (LH). LH normally travels from the pituitary via the blood stream to the testes where it triggers the production and release of testosterone. Without LH, the testes shut down their production of testosterone, causing testicular atrophy ("shrinking testicles"). In males, hCG mimics LH and helps restore / maintain testosterone production in the testes. As such, hCG is commonly used during and after steroid cycles to maintain and restore testicular size as well as endogenous testosterone production. However, if hGC is used for too long and in too high a dose, the resulting rise in natural testosterone will eventually inhibit its own production via negative feedback on the hypothalamus and pituitary.

Before taking any prescription medicine, it is important that you consult your doctor!