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Specimen Atlas of Research Peptides81 plates · MIT
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31Plate 31FDA approved · 1977Reviewed 2026-04-27

HCG

Glycoprotein Hormone

also known as human chorionic gonadotropin, chorionic gonadotrophin, hCG, recombinant hCG, urinary hCG

Placental glycoprotein hormone structurally homologous to luteinizing hormone (LH). Binds LH receptors on Leydig cells, stimulating testosterone synthesis and spermatogenesis. FDA-approved for cryptorchidism, prepubertal cryptorchidism, and hypogonadotropic hypogonadism. In males with hypogonadotropic hypogonadism, hCG monotherapy or combined with FSH restores spermatogenesis in 70–90% of azoospermic patients, achieving pregnancies in 60–80% of cases.

§ I

At a glance

Typical dose (2×/wk)
2,000 IU
Sperm induction rate
70–90%
Time to sperm appearance
12–24 mo
Route

IM or SQ · 2–3×/week

§ II

Mechanism

Edit ↗

Primary target — LH receptors on testicular Leydig cells [schrderlange-2025].

Pathway — hCG → Leydig cell LH receptor → Intracellular cAMP → Steroidogenesis pathway activation → Testosterone synthesis.

Downstream effect — Elevated intratesticular testosterone, restored spermatogenesis, virilization, secondary sex characteristic development [konsam-2026][zachariou-2026].

Origin — Heterodimeric glycoprotein (alpha subunit shared with LH/FSH/TSH; beta subunit confers specificity). Available as urinary-derived or recombinant formulations..

Feedback intact — No — exogenous hCG bypasses hypothalamic-pituitary axis; endogenous LH remains suppressed.

§ III

Dosage

Protocols described in the cited literature; not medical advice.

Edit ↗
ParameterValue
Hypogonadotropic hypogonadism (monotherapy)2,000 IU IM/SQ 2–3×/week [konsam-2026][zachariou-2026]Titrate to normalize testosterone (300–1,000 ng/dL) or achieve target AMH ~7.4 ng/mL.
Combined therapy (hCG + FSH)hCG 2,000 IU 2×/wk + rFSH 75 IU 3×/wk [konsam-2026][nariyoshi-2025]Preferred for azoospermia; FSH added after initial hCG phase or from outset.
Triple therapy (experimental)hCG 2,000 IU 2×/wk + rFSH 75 IU 3×/wk + testosterone 100 mg IM q2wk [konsam-2026]May accelerate virilization; reduces hCG requirements (~30% lower cumulative dose vs monotherapy).
Cryptorchidism (pediatric)500–4,000 IU IM 2–3×/week for 3–6 weeks
Evidence basisRCT / Meta-analysis / FDA-approved [konsam-2026][huijben-2026]
Duration to sperm appearance12–24 months (median ~18 mo) [huijben-2026][zachariou-2026]Congenital HH may require longer treatment; acquired HH responds faster.
RouteIntramuscular or subcutaneous [konsam-2026]
MonitoringSerum testosterone, semen analysis q3–6mo, testicular ultrasoundThickened seminiferous tubules (>300 μm) on ultrasound predict imminent sperm appearance. [nariyoshi-2025]
§ III · b

Reconstitution

A pure mass-to-volume utility. Enter what you have in the vial; the atlas computes the volume per dose. No prescription information.

Inputs
mg
mL
mcg
The calculator does pure mass-to-volume math. It does not recommend a dose. Refer to HCG's cited literature for protocol specifics.
Volumetric outputFig. C — reconstitution math
Volume per dose
0.100mL
10.0 units on a U-100 insulin syringe
Concentration
2500
mcg per mL
Doses per vial
20
at this dose
§ V

Adverse events

Severities follow the FDA / CTCAE convention.

Edit ↗
Injection site reactionmild
Pain, erythema (mild, transient)
Gynecomastiamoderate
Aromatization of elevated testosterone to estradiol; dose-dependent
Testicular discomfort / Edemamild
Rapid testicular growth in hypogonadal males; usually self-limiting
Polycythemiamoderate
Elevated hematocrit from supraphysiological testosterone; monitor CBC
Mood / Libido changesmild
Variable; usually positive with normalization of testosterone
Acne / Oily skinmild
Androgen-mediated; dose-dependent
Prostate concernsmoderate
Monitor PSA in older males; hCG restores physiological testosterone (not supraphysiological)
Antibody formationmild
Rare with recombinant; possible with urinary-derived
Absolute contraindications
  • Androgen-dependent malignancy (prostate, breast cancer)
  • Hypersensitivity to hCG or excipients
  • Precocious puberty
Relative contraindications
  • Untreated obstructive sleep apnea
  • Severe cardiovascular disease (polycythemia risk)
  • History of thromboembolism
§ VI

Administration

Edit ↗
  1. 01
    Reconstitution (if lyophilized)

    Add sterile water or bacteriostatic water per manufacturer instructions. Typically 1–2 mL per 5,000–10,000 IU vial. Roll gently — do not shake. Solution should be clear.

  2. 02
    Injection site

    Intramuscular: ventrogluteal, vastus lateralis, or deltoid. Subcutaneous: abdomen, avoiding navel (2-inch radius). Rotate sites to prevent lipohypertrophy.

  3. 03
    Timing

    Administer 2–3 times per week. Consistent weekly schedule recommended (e.g., Monday/Thursday or Monday/Wednesday/Friday).

  4. 04
    Storage

    Lyophilized: room temperature, light-protected. Reconstituted: refrigerate 2–8 °C. Bacteriostatic water extends shelf life to ~30 days; sterile water use within 72 hours.

  5. 05
    Needle selection

    IM: 21–23G, 1–1.5 inch. SQ: 25–27G, 5/8 inch. Inject slowly (30–60 seconds for IM).

Appendix

Sources

23%

of 52 rendered claims carry a resolvable citation.

  1. [huijben-2026]
    Huijben 2026Boosting Male Fertility: The Impact of Gonadotropin Therapy on Hypogonadotropic Hypogonadism-A Systematic Review and Meta-Analysis.
    journal, 2026
  2. [konsam-2026]
    Konsam 2026Comparing the response of triple therapy and conventional treatment in male congenital hypogonadotropic hypogonadism: a randomized controlled trial.
    journal, 2026
  3. [nariyoshi-2025]
    Nariyoshi 2025Alterations in the ultrasound appearance of seminiferous tubules after gonadotropin treatment in patients with azoospermia because of hypogonadotropic hypogonadism.
    journal, 2025
  4. [schrderlange-2025]
    Schröder-Lange 2025Molecular characterization of the murine Leydig cell lines TM3 and MLTC-1.
    journal, 2025
  5. [zachariou-2026]
    Zachariou 2026Fertility Outcomes in Men with Nonobstructive Azoospermia Due to Hypogonadotropic Hypogonadism After Gonadotropin Therapy.
    journal, 2026
Plate composed 2026-04-27 · maturity human-reviewed · schema v1 · 40 fields uncited — open contributions