Side-by-side · Research reference
HCGvsHexarelin
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-REVIEWED19/45 cited
HCG
Glycoprotein Hormone · LH Mimetic
IM or SQ · 2–3×/week
Hexarelin
Hexapeptide GHRP · Cardio-tropic
SQ · Multiple sites · 1–3×/day
01Mechanism of Action
Parameter
HCG
Hexarelin
Primary target
LH receptors on testicular Leydig cellsSchröder-Lange 2025
Ghrelin receptor (GHS-R1a) + cardiac CD36Smith 1996Ghigo 1997
Pathway
hCG → Leydig cell LH receptor → Intracellular cAMP → Steroidogenesis pathway activation → Testosterone synthesis
GHS-R1a → Gαq → Ca²⁺ → GH release. CD36 engagement → direct cardio-tropic actionGhigo 1997
Downstream effect
Elevated intratesticular testosterone, restored spermatogenesis, virilization, secondary sex characteristic developmentKonsam 2026Zachariou 2026
Strong GH pulse + IGF-1 elevation; cardio-protective effects in animal MI modelsGhigo 1997
Feedback intact?
No — exogenous hCG bypasses hypothalamic-pituitary axis; endogenous LH remains suppressed
Yes initially; tachyphylaxis with chronic useGhigo 1997
Origin
Heterodimeric glycoprotein (alpha subunit shared with LH/FSH/TSH; beta subunit confers specificity). Available as urinary-derived or recombinant formulations.
Synthetic hexapeptide His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂Smith 1996
Antibody development
Rare with recombinant; possible with urinary-derived formulations
—
02Dosage Protocols
Parameter
HCG
Hexarelin
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.
—
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.
—
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).
—
Cryptorchidism (pediatric)
500–4,000 IU IM 2–3×/week for 3–6 weeks
—
Evidence basis
RCT / Meta-analysis / FDA-approvedKonsam 2026Huijben 2026
Phase 1 / Phase 2 trialsSmith 1996Ghigo 1997
Duration to sperm appearance
12–24 months (median ~18 mo)Huijben 2026Zachariou 2026
Congenital HH may require longer treatment; acquired HH responds faster.
—
Monitoring
Serum testosterone, semen analysis q3–6mo, testicular ultrasound
Thickened seminiferous tubules (>300 μm) on ultrasound predict imminent sperm appearance.Nariyoshi 2025
—
Frequency
—
1–2× per day max (tachyphylaxis with chronic 3× daily)
Lower / starter dose
—
50 mcg per dose
Duration
—
4–8 weeks on / 4–8 weeks off (tachyphylaxis mitigation)
Reconstitution
—
Bacteriostatic water
Timing
—
Pre-sleep + fasted preferred
04Side Effects & Safety
Parameter
HCG
Hexarelin
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
—
Acne / Oily skin
Androgen-mediated; dose-dependent
—
Prostate concerns
Monitor PSA in older males; hCG restores physiological testosterone (not supraphysiological)
—
Antibody formation
Rare with recombinant; possible with urinary-derived
—
Hunger
—
Strong appetite increase via ghrelin agonism
IGF-1 elevation
—
Strong; monitor with chronic high-dose use
Cancer risk
—
Contraindicated in active malignancy (GH/IGF-1 axis)
Pregnancy / OB
—
Avoid
Absolute Contraindications
HCG
- ·Androgen-dependent malignancy (prostate, breast cancer)
- ·Hypersensitivity to hCG or excipients
- ·Precocious puberty
Hexarelin
- ·Active malignancy
- ·Pregnancy / breastfeeding
- ·Disrupted hypothalamic-pituitary axis
Relative Contraindications
HCG
- ·Untreated obstructive sleep apnea
- ·Severe cardiovascular disease (polycythemia risk)
- ·History of thromboembolism
Hexarelin
- ·Untreated diabetes
- ·Severe hyperprolactinemia
05Administration Protocol
Parameter
HCG
Hexarelin
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 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.
2. Injection site
Intramuscular: ventrogluteal, vastus lateralis, or deltoid. Subcutaneous: abdomen, avoiding navel (2-inch radius). Rotate sites to prevent lipohypertrophy.
SQ — abdomen or thigh. Rotate sites.
3. Timing
Administer 2–3 times per week. Consistent weekly schedule recommended (e.g., Monday/Thursday or Monday/Wednesday/Friday).
Pre-sleep + fasted preferred. Cycle on/off to avoid tachyphylaxis.
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: room temp, 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, 4–8 mm insulin syringe.
06Stack Synergy
HCG
— no documented stacks
Hexarelin
+ CJC-1295 (no DAC)
StrongHexarelin (GHRP) + CJC-1295-no-DAC (GHRH analogue) is the higher-amplitude variant of the standard GHRH+GHRP stack. Hexarelin produces a stronger pulse than ipamorelin but with cortisol + prolactin signal — choose this stack for maximum GH amplitude when side-effect tolerance is acceptable. Cycle aggressively.
- Hexarelin
- 100 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- Maximum GH pulse amplitude (with side-effect signal)