Human Chorionic Gonadotropin

HCG binds LH/hCG receptors in the testes (Leydig cells), directly stimulating testosterone production. Acts as an exogenous LH signal — maintains testicular size and function during periods of HPTA suppression. In women, triggers ovulation by mimicking the LH surge. Identical beta subunit to LH — standard immunoassays cannot distinguish between HCG and LH.

Not a steroid. No ester. Glycoprotein hormone — 237 amino acids. Injectable only — subcutaneous or intramuscular. Short half-life requires frequent administration.

HCG serves two distinct functions in performance contexts. The first is testicular maintenance during anabolic cycles. When exogenous androgens suppress LH production, the testes receive no signal to produce testosterone and begin to atrophy over the duration of the cycle. HCG mimics LH and provides that signal, maintaining testicular size and function. The second function is in post-cycle recovery, where it is used to stimulate endogenous testosterone production before transitioning to SERMs. Some athletes use it throughout a cycle to prevent atrophy while others use it only in the transition period between the end of a cycle and the beginning of PCT.

HCG is not stacked with other compounds in the traditional sense. It is a supportive addition to anabolic protocols rather than a performance compound in itself. It appears alongside virtually any anabolic stack as a maintenance tool for testicular function. During PCT it is typically used in the initial phase before transitioning to SERMs, because its direct LH-mimicking action provides faster initial testosterone stimulation than SERMs, which work upstream through receptor modulation. The standard transition sequence is HCG first, then SERM when HCG is discontinued.

• Male hypogonadism and infertility
• Cryptorchidism — undescended testicles in boys
• Female infertility — ovulation induction
• Hypogonadotropic hypogonadism treatment
• Testosterone production stimulation in hypogonadal men

• Gynecomastia — stimulates testicular aromatase, increasing estrogen production
• Acne
• Fluid retention
• Mood changes
• Ovarian hyperstimulation syndrome (OHSS) in women — potentially life-threatening
• Desensitization of LH receptors with chronic high-dose use
• WADA bans HCG in male athletes as it may be used to stimulate testosterone production and mask natural testosterone suppression

HCG at higher doses stimulates testicular aromatase, which can produce a significant estrogen spike that causes gynecomastia even when overall androgen levels are managed. The receptor desensitization that can occur with chronic high-dose HCG use is one of the more consequential and underappreciated risks, as it can impair the LH receptor responsiveness that is necessary for natural testosterone recovery after the cycle ends. Using HCG improperly, particularly for too long or at too high a dose, can paradoxically make post-cycle recovery harder rather than easier.

Very short detection window of 2-3 days via urinary immunoassay. WADA testing specifically targets HCG in male athletes.