HCG

What It Is

Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone naturally produced by trophoblast cells of the placenta during pregnancy. It structurally mimics luteinizing hormone (LH) and binds to the LH/CG receptor, stimulating testosterone production in Leydig cells and supporting corpus luteum progesterone secretion. Pharmaceutical hCG is FDA-approved for specific indications: treatment of hypogonadotropic hypogonadism in males, prepubertal cryptorchidism, and as part of assisted reproductive technology (ART) to trigger ovulation. In reproductive medicine, hCG injection is the standard trigger for final oocyte maturation in IVF cycles, though kisspeptin and GnRH agonist triggers are being studied as alternatives that may reduce ovarian hyperstimulation syndrome (OHSS) risk. In male hormone therapy, hCG is commonly used alongside testosterone replacement therapy (TRT) to maintain intratesticular testosterone levels and preserve fertility by preventing testicular atrophy. Recombinant hCG (choriogonadotropin alfa, brand name Ovidrel) and urinary-derived preparations (Pregnyl, Novarel) are both commercially available. hCG is classified as a prohibited substance by WADA in male athletes. Misuse concerns exist around weight-loss programs promoting very low-calorie diets combined with hCG injections — the FDA has warned that hCG is not approved or effective for weight loss.

Why Researchers Study It

HCG is a cornerstone of reproductive endocrinology research due to its structural similarity to LH and its ability to directly stimulate gonadal steroidogenesis. It remains the gold standard for maintaining intratesticular testosterone during exogenous testosterone therapy, preserving both Leydig cell function and spermatogenesis.

Proposed Mechanisms

• Mimics luteinizing hormone (LH) by binding the LH/CG receptor on Leydig cells
• Stimulates intratesticular testosterone production independent of pituitary signaling
• Maintains spermatogenesis during exogenous testosterone use
• In women, triggers final oocyte maturation and ovulation in assisted reproduction

Evidence Snapshot

Commonly Discussed Benefits

Safety & Cautions

Comparisons

See how HCG compares to related peptides:

Calculator Tools

Use our research tools to explore dosing and reconstitution data:

Citations

1. [1] Coviello AD. et al. — Effects of graded doses of testosterone on spermatogenesis and HCG. JCEM. 2008 PubMed

Related Peptides