HCG

Introduction

Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by syncytiotrophoblast cells of the placenta. Heterodimer of an α-subunit (shared with LH, FSH, TSH) and a unique β-subunit. Pharmaceutical preparations are derived from purified urinary sources (uhCG) or produced recombinantly (rhCG). FDA-approved for several specific endocrine indications; widely used off-label and in research.

Mechanism of Action

Binds and activates the LH/CG receptor (LHCGR) on Leydig cells, theca cells, and corpus luteum cells. In men this drives intratesticular testosterone synthesis and supports spermatogenesis. In women it triggers ovulation when administered after follicular maturation.

Approved and Investigated Indications

Approved: ovulation induction in selected anovulatory infertility; hypogonadotropic hypogonadism in males; prepubertal cryptorchidism unrelated to anatomic obstruction. Off-label/research: testicular preservation during exogenous testosterone therapy, post-cycle androgen-recovery protocols, and adjunct in male fertility evaluations.

Reconstitution

Typical 10,000 IU lyophilized vial: add 10 mL of bacteriostatic water, swirl gently. Final concentration 1000 IU/mL — each 0.1 mL (10 units on a U-100 insulin syringe) delivers 100 IU. A 5000 IU vial reconstituted with 5 mL yields the same 1000 IU/mL.

Dosing Protocol (research literature)

Male hypogonadotropic hypogonadism / testicular support: 500–1500 IU subcutaneously 2–3 times per week. Testicular preservation during TRT: 250–500 IU SC every 3 days. Ovulation trigger (clinical fertility setting): 5,000–10,000 IU IM as a single dose post-follicular maturation. Cryptorchidism (pediatric): per pediatric endocrinology protocol — not addressed here.

Administration

IM or SC. SC is preferred for chronic male protocols (less injection-related discomfort). IM for single-dose ovulation trigger.

Storage & Handling

Lyophilized: refrigerate (2–8°C). Reconstituted: refrigerate; stable approximately 30–60 days with bacteriostatic water (longer than most peptides). Protect from light.

Side Effects

Injection-site reactions, headache, fatigue, mood changes. Gynecomastia in men via downstream estrogen aromatization. Serious in women: ovarian hyperstimulation syndrome (OHSS) and thromboembolism with ovulation-induction protocols; multiple gestation.

Contraindications

Androgen- or estrogen-dependent malignancies, undiagnosed abnormal genital bleeding, precocious puberty, prior thromboembolic disease.

Monitoring

Male protocols: baseline total testosterone, free testosterone, estradiol, LH, FSH, hematocrit, PSA (age-appropriate). Re-measure at 4–6 weeks and adjust dose; manage estrogen aromatization with an aromatase inhibitor if needed (per clinician). Ovulation-induction protocols require serial transvaginal ultrasound and estradiol monitoring per fertility-clinic standard of care.

Disclaimer

This article is for informational and research-reference purposes only. Nothing in this document constitutes medical advice, a prescription, or a recommendation from a physician. The reconstitution, dosing, and protocol information above reflects ranges commonly cited in published research and clinician-directed protocols — it is provided as reference material only, not as instructions, an endorsement of off-label use, or a substitute for individualized medical evaluation.

Customers should do their own research and consult their own physician before considering any peptide protocol. Whether a given compound is appropriate for an individual — and at what dose, for what duration, and alongside what monitoring — is a decision that only a licensed clinician with knowledge of that individual's medical history, current medications, and conditions can make.

The platform and the author make no claim that any compound described here is safe, effective, or appropriate for any particular person or purpose, and accept no responsibility for outcomes arising from self-directed use of the information.