Side-by-side · Research reference
GHRP-2vsHCG
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 2HUMAN-REVIEWED15/42 cited
BFDA-ApprovedHUMAN-REVIEWED12/52 cited
GHRP-2
Hexapeptide GHRP · Phase 2 (clinical diagnostic)
SQ · Multiple sites · 1–3×/day
HCG
Glycoprotein Hormone · LH Mimetic
IM or SQ · 2–3×/week
01Mechanism of Action
Parameter
GHRP-2
HCG
Primary target
Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990
LH receptors on testicular Leydig cellsSchröder-Lange 2025
Pathway
GHS-R1a → Gαq → Ca²⁺ → GH vesicle exocytosisBowers 2002
hCG → Leydig cell LH receptor → Intracellular cAMP → Steroidogenesis pathway activation → Testosterone synthesis
Downstream effect
Strong GH pulse + IGF-1 elevation; appetite increase via ghrelin agonismBowers 2002
Elevated intratesticular testosterone, restored spermatogenesis, virilization, secondary sex characteristic developmentKonsam 2026Zachariou 2026
Feedback intact?
Yes, with somatostatin feedback active
No — exogenous hCG bypasses hypothalamic-pituitary axis; endogenous LH remains suppressed
Origin
Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 1990
Heterodimeric glycoprotein (alpha subunit shared with LH/FSH/TSH; beta subunit confers specificity). Available as urinary-derived or recombinant formulations.
Antibody development
—
Rare with recombinant; possible with urinary-derived formulations
02Dosage Protocols
Parameter
GHRP-2
HCG
Frequency
1–3× per day
—
Lower / starter dose
50 mcg per dose
—
Evidence basis
Phase 2 + clinical diagnostic useBowers 1990
RCT / Meta-analysis / FDA-approvedKonsam 2026Huijben 2026
Duration
8–12 weeks on / 4 off (anecdotal)
—
Reconstitution
Bacteriostatic water
—
Timing
Pre-sleep + fasted preferred
—
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
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
04Side Effects & Safety
Parameter
GHRP-2
HCG
Prolactin elevation
Mild but measurable
—
Hunger
Strong appetite increase
—
Injection site reaction
Mild erythema
Pain, erythema (mild, transient)
IGF-1 elevation
Strong; monitor with chronic high-dose use
—
Cancer risk
Contraindicated in active malignancy
—
Pregnancy / OB
Avoid
—
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
Absolute Contraindications
GHRP-2
- ·Active malignancy
- ·Pregnancy / breastfeeding
HCG
- ·Androgen-dependent malignancy (prostate, breast cancer)
- ·Hypersensitivity to hCG or excipients
- ·Precocious puberty
Relative Contraindications
GHRP-2
- ·Untreated diabetes
HCG
- ·Untreated obstructive sleep apnea
- ·Severe cardiovascular disease (polycythemia risk)
- ·History of thromboembolism
05Administration Protocol
Parameter
GHRP-2
HCG
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.
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. Injection site
SQ — abdomen or thigh. Rotate sites.
Intramuscular: ventrogluteal, vastus lateralis, or deltoid. Subcutaneous: abdomen, avoiding navel (2-inch radius). Rotate sites to prevent lipohypertrophy.
3. Timing
Pre-sleep + fasted preferred.
Administer 2–3 times per week. Consistent weekly schedule recommended (e.g., Monday/Thursday or Monday/Wednesday/Friday).
4. Storage
Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.
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. Needle
29–31G, 4–8 mm insulin syringe.
IM: 21–23G, 1–1.5 inch. SQ: 25–27G, 5/8 inch. Inject slowly (30–60 seconds for IM).
06Stack Synergy
GHRP-2
+ CJC-1295 (no DAC)
StrongGHRP-2 + CJC-1295-no-DAC is a higher-amplitude alternative to the ipamorelin + CJC-1295 stack. GHRP-2 produces a stronger pulse but with cortisol + prolactin signal — choose when maximum GH amplitude is the goal and the side-effect tolerance is acceptable.
- GHRP-2
- 100–200 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- High-amplitude GH pulse, body composition
HCG
— no documented stacks