hCG (Human Chorionic Gonadotropin) vs Micronized Progesterone

Mechanism

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.

Standard Dosing

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

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.

Cycle 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.

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)

Contraindications

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

Best Stacking Partners

Mechanism

Bioidentical progesterone used to support luteal balance, sleep architecture, and selected HRT protocols.

Contraindications

• Hormone-sensitive conditions without specialist oversight