Hormones

hCG (Human Chorionic Gonadotropin)

Evidence: strong_human

Mechanism of Action

hCG mimics luteinizing hormone (LH) by binding the LH/CG receptor on testicular Leydig cells, activating the cAMP-PKA signaling cascade that upregulates steroidogenic acute regulatory protein (StAR) and CYP11A1, driving cholesterol conversion to pregnenolone and downstream testosterone synthesis. By maintaining intratesticular testosterone (ITT) levels during exogenous testosterone administration, hCG preserves Leydig cell function, spermatogenesis, testicular volume, and the production of neurosteroids (pregnenolone, DHEA) and estradiol within the testes.

Dosing Protocol

Standard: Research indicates 250-500 IU administered subcutaneously 2-3 times per week as a TRT adjunct for fertility and testicular maintenance.

Loading: Research indicates 1000-1500 IU three times per week for 2-4 weeks to restore testicular function after prolonged suppression.

Maintenance: Research indicates 250-500 IU twice weekly ongoing alongside TRT.

Administration: subcutaneousintramuscular

Timing: Administer on non-testosterone injection days if using twice-weekly TRT split. Consistent schedule (e.g., Tuesday/Saturday). Refrigerate reconstituted solution; use within 30-60 days.

Duration: Ongoing for as long as TRT continues and fertility preservation is desired. Can be used in 4-8 week pre-PCT bursts to 'prime' testicular recovery.

Notes

hCG is the gold-standard TRT adjunct for fertility preservation. The American Urological Association recommends hCG for men with testosterone deficiency who desire to maintain fertility. CRITICAL: Leydig cell desensitization occurs at high doses — do not exceed 1500 IU per injection. Required bloodwork: Total testosterone, estradiol (sensitive assay — hCG significantly raises E2), LH/FSH (will be suppressed on TRT regardless), semen analysis if fertility is the goal, beta-hCG levels if monitoring compliance. Monitor estradiol closely; if E2 rises above 40-50 pg/mL with symptoms, consider low-dose AI. Medical supervision required.

Stacking

  • Testosterone Cypionate/Enanthate (primary use as TRT adjunct)
  • Clomiphene (PCT protocol)
  • Anastrozole (if hCG elevates estradiol excessively)

Interactions

  • Testosterone (exogenous) [LOW] — Synergistic — hCG maintains intratesticular testosterone that exogenous T suppresses. This is the primary intended combination.
  • Aromatase inhibitors [LOW] — hCG stimulates intratesticular aromatase, increasing estradiol. AI may be needed in sensitive individuals.
  • FSH (recombinant) [LOW] — Combined hCG+FSH protocol used for fertility restoration when hCG alone is insufficient.

Contraindications

  • Androgen-dependent neoplasia (prostate cancer)
  • Precocious puberty
  • hCG-secreting tumors
  • Known hypersensitivity to hCG

Side Effects

  • Elevated estradiol (from intratesticular aromatization)
  • Injection site reactions
  • Headache
  • Gynecomastia (if E2 rises unchecked)
  • Mood swings
  • Potential Leydig cell desensitization at excessive doses (>1500 IU per dose)

Key Papers

  • 10.1016/j.fertnstert.2004.01.024
  • 10.4103/2305-0500.246336
  • 10.1038/s41443-018-0053-x

Source Quality

Pharmaceutical-grade hCG (Pregnyl, Novarel) preferred. Compounding pharmacy reconstituted hCG with bacteriostatic water is acceptable. Store lyophilized powder at room temperature; reconstituted solution must be refrigerated at 2-8C.

Disclaimer: This information is for educational purposes only and is not medical advice. BioAccelera Labs does not diagnose, treat, or prescribe. Consult a licensed healthcare provider before using any compound.

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