FSH vs hCG

Binds FSH receptors on Sertoli cells in testes to support sperm maturation and inhibin B production. In women, binds granulosa cell FSH receptors to drive follicular growth and estradiol production.

FSH (follicle-stimulating hormone) is an endogenous heterodimeric glycoprotein hormone produced and secreted by pituitary gonadotrophs, composed of a non-covalently associated common alpha subunit shared with LH, TSH, and hCG, and a unique FSH-specific beta subunit that confers receptor specificity; it is the primary regulator of gametogenesis in both sexes, acting on ovarian granulosa cells and testicular Sertoli cells to drive reproductive development. FSH activates its cognate receptor (FSHR) through cAMP-mediated signaling to stimulate follicular maturation and estradiol synthesis in the ovary via aromatase upregulation, and to support spermatogenesis in the testis by promoting Sertoli cell function and germ cell proliferation; FSH levels rise dramatically at menopause as negative feedback from ovarian estrogen declines. A Cochrane systematic review and meta-analysis established that recombinant FSH preparations are clinically equivalent to urinary-derived gonadotropins for ovarian stimulation in assisted reproductive technology cycles, providing the evidence base underlying current ART practice; this review supports the use of recombinant FSH as the standard of care for controlled ovarian hyperstimulation. FDA-approved recombinant FSH preparations — follitropin alfa (Gonal-f) and follitropin beta (Follistim) — require a prescription and are indicated for ovulation induction and ART in women and for hypogonadotropic hypogonadism in men; endogenous FSH is not administered as a therapeutic agent, and research-grade recombinant FSH is used as a cell culture tool and reproductive biology research compound.

Glycoprotein hormone binding LH receptor on Leydig cells; stimulates testosterone production; prevents testicular atrophy during TRT; maintains spermatogenesis via FSH-like activity

Human chorionic gonadotropin (hCG) is a glycoprotein hormone that acts as a functional analogue of luteinizing hormone (LH), binding to LH receptors on Leydig cells in the testes and granulosa cells in the ovaries to stimulate steroidogenesis. In men, hCG stimulates testicular testosterone production directly, making it a widely used clinical tool for hypogonadotropic hypogonadism, male fertility support, and preservation of testicular function alongside testosterone replacement therapy. Clinical research demonstrates hCG effectiveness for improving testosterone levels and sperm parameters in males with gonadotropin deficiency, as well as for triggering final oocyte maturation in IVF protocols. hCG is an FDA-regulated biologic available in multiple approved formulations; use requires physician supervision due to dose-dependent effects on testosterone, estradiol, and reproductive signaling. hCG dosage in TRT support: in men using testosterone replacement therapy, hCG is prescribed to prevent testicular atrophy and maintain intratesticular testosterone levels needed for spermatogenesis. Typical clinical doses range from 250 to 500 IU subcutaneously administered 2–3 times per week, though protocols vary by provider and individual response. At higher doses, hCG's stimulation of testicular testosterone can also increase aromatization to estradiol — a clinically relevant consideration in TRT management requiring estrogen monitoring. hCG vs gonadorelin: both are used in men's health for testicular preservation alongside TRT, but they act at different axis levels. hCG acts directly on Leydig cell LH receptors, bypassing the pituitary entirely — a direct trophic signal to the testes. Gonadorelin acts upstream at the pituitary to stimulate endogenous LH and FSH release, preserving the full hypothalamic-pituitary-gonadal axis including FSH-driven spermatogenesis. For men prioritizing sperm production, gonadorelin's preservation of FSH signaling offers a potential advantage; for men primarily focused on testicular volume and intratesticular testosterone maintenance, hCG provides a well-validated, direct approach. Telehealth and men's health providers offering hCG and gonadorelin protocols are listed in the PeptideBase directory.