HCG (Human Chorionic Gonadotropin)

HCG (human chorionic gonadotropin) is a glycoprotein hormone that closely mimics luteinizing hormone (LH). It binds LH receptors on the Leydig cells of the testes, signaling them to produce testosterone directly inside the testis. Because it acts downstream of the pituitary, it can stimulate testicular testosterone even when the body's own LH signal is suppressed.

Testosterone replacement therapy suppresses the body's own LH, which shuts down intratesticular testosterone production and can shrink the testes and impair sperm production. In a 2013 study (Hsieh et al., J Urol), men on testosterone plus low-dose HCG (500 IU every other day) maintained semen parameters and none became azoospermic. HCG is used in research and clinical protocols to preserve testicular size and fertility during testosterone therapy.

HCG potency is measured in international units (IU) of biological activity, not milligrams of mass — so it is sold as 5,000 IU vials and dosed in IU. Community and clinical protocols for testicular support during testosterone therapy commonly reference roughly 250-500 IU two to three times per week; fertility-restoration and post-cycle protocols use higher amounts. It is reconstituted with bacteriostatic water and injected subcutaneously or intramuscularly.

Yes. HCG is the active ingredient in FDA-approved prescription products used for conditions such as hypogonadotropic hypogonadism and infertility. The research-peptide and compounded HCG sold by peptide vendors is not FDA-approved and is labeled for research purposes only. This page reports what published research and community sources document, not medical advice.

In men with hypogonadotropic hypogonadism, gonadotropin therapy built around HCG (often combined with FSH) has been reported to induce spermatogenesis in roughly 80% of patients and pregnancy in about half over 12-24 months (reviewed by Boeri et al., 2021). A 2021 review (Fink et al.) describes HCG as a viable option for secondary hypogonadism because it raises testosterone while supporting, rather than suppressing, sperm production.

Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.

Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.

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