HCG
Gonadotropin (LH analog)
Studied for maintaining testicular function and endogenous steroidogenesis during suppression of the HPG axis.
How it works
HCG, human chorionic gonadotropin, is studied for its structural and functional similarity to luteinizing hormone, allowing it to bind LH receptors on Leydig cells in the testes. This mimics the natural signal that drives endogenous testosterone production within the testicular tissue itself.
Its main research application is maintaining intratesticular testosterone and testicular volume during periods when the hypothalamic-pituitary-gonadal axis is suppressed, such as during exogenous androgen administration in other research contexts, since suppression of the axis would otherwise halt this local signal.
Clinical studies in this context report preserved intratesticular testosterone levels and maintained testicular volume when HCG is included, supporting its role as an adjunct compound rather than a primary research target on its own.
What research has shown
Clinical studies report preserved intratesticular testosterone and testicular volume during exogenous androgen use.
Reported ranges in the literature
Low end
250 IU 2× weekly
Optimal
500 IU 2 to 3× weekly
High end
1,000 to 1,500 IU 3× weekly (restart protocols)
Frequency reported in the literature: 2 to 3× weekly
Frequently asked questions
What is HCG?
HCG is a gonadotropin studied for maintaining testicular function and endogenous steroidogenesis, particularly during suppression of the HPG axis.
How does HCG work compared with LH?
HCG binds the same LH receptor on Leydig cells and produces a similar downstream signal, but has a longer circulating half-life than natural LH, which is part of why it is studied as a substitute signal.
What does the research show?
Clinical studies report preserved intratesticular testosterone and testicular volume when HCG is included during exogenous androgen administration research.
How is HCG stored?
Lyophilized HCG vials are stored refrigerated prior to reconstitution, and refrigerated with a defined use window afterward, consistent with general peptide hormone stability data.
How long are research blocks typically?
Published protocols describe 2 to 3 times weekly administration, with restart-focused protocols sometimes using a shorter, more frequent schedule.
Related compounds
Further reading
Research use only
All content on this page is general reference information for laboratory research contexts. It is not medical advice, is not intended to direct human use, and does not replace guidance from a licensed healthcare professional. Not for human consumption. Must be 18+.