Human chorionic gonadotropin (HCG) is a glycoprotein hormone naturally produced by the placenta during pregnancy. It shares structural homology with LH (luteinizing hormone) and binds to LH receptors with equal affinity, producing the same downstream biological effects.

In men on testosterone replacement therapy, HCG is co-administered to maintain testicular function that is suppressed by exogenous testosterone. Without HCG, TRT suppresses the HPG axis — causing testicular atrophy and azoospermia. HCG keeps the testes stimulated and functional.

In women, HCG is a cornerstone of fertility protocols — used to trigger ovulation in IUI and IVF cycles, support the corpus luteum after ovulation, and maintain early pregnancy progesterone levels.

LH Receptor Agonism (Men)
HCG binds to LH receptors on Leydig cells in the testes, stimulating testosterone synthesis and maintaining intratesticular testosterone concentrations necessary for spermatogenesis — even when systemic TRT has suppressed pituitary LH secretion.

Ovulation Trigger (Women)
In fertility protocols, HCG is administered to mimic the endogenous LH surge, triggering final oocyte maturation and ovulation 36–40 hours after injection.

Corpus Luteum Support
Post-ovulation, HCG maintains the corpus luteum's progesterone production, supporting the uterine lining during early implantation and pregnancy.

Men on TRT (testicular maintenance): 250–500 IU SubQ 2–3x per week alongside testosterone

Male fertility (hypogonadotropic hypogonadism): 1000–2000 IU IM 3x per week

Women — ovulation trigger: 5000–10,000 IU single IM or SubQ injection per fertility protocol

Dosing determined by indication and monitored by a fertility specialist or hormone therapy provider.