Storage Stability
Mechanism of Action
LH Receptor Agonism
hCG binds and activates LH receptors (LHR) on testicular Leydig cells with greater potency and longer duration than endogenous LH, due to its longer half-life (24–36 vs ~30 min for LH).Testosterone Production
LHR activation in Leydig cells stimulates cAMP production, activating the steroidogenic pathway: cholesterol → pregnenolone → progesterone → androstenedione → testosterone.Testicular Volume Preservation
Exogenous testosterone suppresses HPG axis LH/FSH, causing testicular atrophy. hCG bypasses the pituitary and directly stimulates Leydig cells, maintaining testicular volume and intratesticular testosterone even during TRT.Research Summary
TRT Co-administration
Multiple studies confirm hCG at 250–500 IU 2–3x/week during TRT maintains testicular volume and intratesticular testosterone levels, preserving fertility potential.Fertility
HCG 5,000–10,000 IU triggers the LH surge for follicle rupture and ovulation in ART protocols. Recombinant hCG (Ovidrel) is equivalent to urinary-derived (Pregnyl) in clinical outcomes.Male Hypogonadism
HCG monotherapy (1,000–3,000 IU 3x/week) raises testosterone into normal range in secondary hypogonadism (intact pituitary + testes), avoiding exogenous testosterone suppression.Calculate your HCG dose Vial strength, BAC water, exact syringe draw in IU. Free, no signup. Open Calc →
Research Protocols
TRT Support Protocol
250–500 IU subcutaneously 2–3x weekly alongside TRT. Higher doses are generally not more effective for testicular maintenance.Post-Cycle / Restart
500–1,000 IU 3x/week for 3–4 weeks to restore HPG axis function and intratesticular testosterone before SERM-based PCT.Reconstitution
Reconstitutte lyophilized" class="wiki-gloss-link">lyophilized hCG with provided bacteriostatic water. Refrigerate and use within 30–60 days.Storage & Handling
Store lyophilized powder at room temperature or 2–8°C. After reconstitution, refrigerate at 2–8°C and use within 30 days (Pregnyl) or per manufacturer specs. Do not freeze reconstituted solution.
References
- [1]Coviello AD, et al. "Low-dose hCG maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression." JCEM, 2005.
- [2]Hammar M, et al. "HCG treatment restores testicular size during TRT." Andrologia, 1985.
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