Side-by-side · Research reference
HCGvsMelanotan-II
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AFDA-ApprovedHUMAN-REVIEWED12/52 cited
BPhase 1HUMAN-REVIEWED9/43 cited
HCG
Glycoprotein Hormone · LH Mimetic
IM or SQ · 2–3×/week
01Mechanism of Action
Parameter
HCG
Melanotan-II
Primary target
LH receptors on testicular Leydig cellsSchröder-Lange 2025
MC1R (skin) + MC3R + MC4R (CNS sexual / appetite)Dorr 1996
Pathway
hCG → Leydig cell LH receptor → Intracellular cAMP → Steroidogenesis pathway activation → Testosterone synthesis
MC1R agonism → melanocyte tyrosinase → eumelanin synthesis. MC4R → autonomic sexual arousal centresDorr 1996Simerly 2023
Downstream effect
Elevated intratesticular testosterone, restored spermatogenesis, virilization, secondary sex characteristic developmentKonsam 2026Zachariou 2026
Skin darkening, photo-protection, increased sexual desire / spontaneous erectionDorr 1996
Feedback intact?
No — exogenous hCG bypasses hypothalamic-pituitary axis; endogenous LH remains suppressed
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Origin
Heterodimeric glycoprotein (alpha subunit shared with LH/FSH/TSH; beta subunit confers specificity). Available as urinary-derived or recombinant formulations.
Cyclic 7-AA modified α-MSH analog; designed at University of ArizonaDorr 1996
Antibody development
Rare with recombinant; possible with urinary-derived formulations
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02Dosage Protocols
Parameter
HCG
Melanotan-II
Hypogonadotropic hypogonadism (monotherapy)
2,000 IU IM/SQ 2–3×/weekKonsam 2026Zachariou 2026
Titrate to normalize testosterone (300–1,000 ng/dL) or achieve target AMH ~7.4 ng/mL.
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Combined therapy (hCG + FSH)
hCG 2,000 IU 2×/wk + rFSH 75 IU 3×/wkKonsam 2026Nariyoshi 2025
Preferred for azoospermia; FSH added after initial hCG phase or from outset.
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Triple therapy (experimental)
hCG 2,000 IU 2×/wk + rFSH 75 IU 3×/wk + testosterone 100 mg IM q2wkKonsam 2026
May accelerate virilization; reduces hCG requirements (~30% lower cumulative dose vs monotherapy).
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Cryptorchidism (pediatric)
500–4,000 IU IM 2–3×/week for 3–6 weeks
—
Duration to sperm appearance
12–24 months (median ~18 mo)Huijben 2026Zachariou 2026
Congenital HH may require longer treatment; acquired HH responds faster.
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Monitoring
Serum testosterone, semen analysis q3–6mo, testicular ultrasound
Thickened seminiferous tubules (>300 μm) on ultrasound predict imminent sperm appearance.Nariyoshi 2025
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Maintenance
—
0.5–1.0 mg 1–2×/week
After visible tan develops; supports with UV exposure.
Frequency
—
Daily during loading; 1–2× per week maintenance
Lower / starter dose
—
0.1 mg / day
Conservative starter — assess tolerability for nausea.
Duration
—
8–12 weeks per cycle
Reconstitution
—
Bacteriostatic water; protect from light
Timing
—
Evening preferred (24h tan-development cycle)
Half-life
—
~1 hour plasma; effects on melanocytes persist days
04Side Effects & Safety
Parameter
HCG
Melanotan-II
Injection site reaction
Pain, erythema (mild, transient)
—
Gynecomastia
Aromatization of elevated testosterone to estradiol; dose-dependent
—
Testicular discomfort / Edema
Rapid testicular growth in hypogonadal males; usually self-limiting
—
Polycythemia
Elevated hematocrit from supraphysiological testosterone; monitor CBC
—
Mood / Libido changes
Variable; usually positive with normalization of testosterone
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Acne / Oily skin
Androgen-mediated; dose-dependent
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Prostate concerns
Monitor PSA in older males; hCG restores physiological testosterone (not supraphysiological)
—
Antibody formation
Rare with recombinant; possible with urinary-derived
—
Nausea
—
Common, especially loading phase
Flushing
—
Common transient
Increased mole / freckle pigmentation
—
Existing moles darken; new lesions possible
Melanoma risk
—
Theoretical concern — increased melanocyte activity; CAUTION in melanoma history
Appetite suppression
—
MC4R-mediated; mild
Pregnancy / OB
—
Contraindicated
Absolute Contraindications
HCG
- ·Androgen-dependent malignancy (prostate, breast cancer)
- ·Hypersensitivity to hCG or excipients
- ·Precocious puberty
Melanotan-II
- ·History of melanoma or atypical mole syndrome
- ·Pregnancy / breastfeeding
- ·Active uncontrolled hypertension
Relative Contraindications
HCG
- ·Untreated obstructive sleep apnea
- ·Severe cardiovascular disease (polycythemia risk)
- ·History of thromboembolism
Melanotan-II
- ·Significant freckling / dysplastic nevus
- ·Personal or family melanoma history
05Administration Protocol
Parameter
HCG
Melanotan-II
1. 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.
Add 2 mL bacteriostatic water to 10 mg vial → 5 mg/mL = 500 mcg per 0.1 mL. Light-protected.
2. Injection site
Intramuscular: ventrogluteal, vastus lateralis, or deltoid. Subcutaneous: abdomen, avoiding navel (2-inch radius). Rotate sites to prevent lipohypertrophy.
SQ — abdomen. Rotate sites.
3. Timing
Administer 2–3 times per week. Consistent weekly schedule recommended (e.g., Monday/Thursday or Monday/Wednesday/Friday).
Evening preferred. UV exposure (sunlight or tanning bed) helps develop tan.
4. 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.
Lyophilised: refrigerate, light-protected. Reconstituted: refrigerate ≤30 days.
5. Needle selection
IM: 21–23G, 1–1.5 inch. SQ: 25–27G, 5/8 inch. Inject slowly (30–60 seconds for IM).
29–31G insulin syringe.