HCG (Human Chorionic Gonadotropin)

HCG (Human Chorionic Gonadotropin) is a glycoprotein hormone naturally produced during pregnancy that shares structural similarity with luteinizing hormone (LH) and binds to the same receptor. FDA-approved indications include treatment of female infertility (to induce ovulation), male hypogonadism, and cryptorchidism. HCG stimulates Leydig cells in the testes to produce testosterone, making it useful for maintaining testicular function during testosterone replacement therapy or after anabolic steroid cycles. In fertility medicine, HCG triggers final oocyte maturation and ovulation in assisted reproductive technologies. The hormone is administered via intramuscular or subcutaneous injection with various protocols depending on the indication. Research supports its use in maintaining intratesticular testosterone and spermatogenesis when exogenous androgens would otherwise suppress the HPG axis. HCG has also been used off-label for weight loss in combination with very-low-calorie diets, though evidence for this application is controversial and not supported by clinical trials. Side effects may include gynecomastia, fluid retention, and headache.

Approved uses are narrow (infertility, hypogonadism, cryptorchidism); the weight-loss application is refuted by meta-analyses; misuse in sports is prohibited (WADA); monitoring for side effects such as gynecomastia, fluid retention, and injection-site reactions is needed.

Glycoprotein hormone (alpha + beta subunits) acting as an LH agonist at the LHCG receptor; administered IM/SC. Half-life is ~24-33 hours (terminal, varies by formulation), supporting dosing every 2-3 days in hypogonadism protocols. Stimulates Leydig-cell testosterone production and triggers ovulation/oocyte maturation in ART.