HCG

Volume Pricing

Price per pack (10 vials). Discount applies to this compound only – no mix and match.

HCG — LH/CG Receptor Agonist | Gonadotropin

Human Chorionic Gonadotropin (HCG) is a naturally occurring glycoprotein hormone produced by the placenta during pregnancy, and one of the most extensively studied gonadotropins in endocrinology research. Composed of two non-covalently bonded subunits — an alpha (α) subunit shared with LH, FSH, and TSH, and a unique beta (β) subunit that confers its biological specificity — HCG functions as a potent agonist at the luteinizing hormone/choriogonadotropin receptor (LHCGR). Its structural homology to luteinizing hormone (LH), combined with a significantly longer half-life (approximately 36 hours versus LH’s ~30 minutes), makes it a uniquely valuable tool for studying gonadotropin signaling, steroidogenesis, HPG axis dynamics, and reproductive endocrinology in both male and female models.

Why HCG’s Receptor Profile Matters

HCG binds with high affinity to the LHCGR — the same receptor activated by endogenous LH — but with substantially greater receptor occupancy duration due to its extended half-life. This distinction makes HCG a more potent and sustained agonist than LH itself in stimulating downstream steroidogenic pathways. Upon receptor binding, HCG activates G protein-coupled signaling cascades including cAMP/PKA and PKC, leading to upregulation of steroidogenic enzymes in Leydig cells (males) and luteal/granulosa cells (females).

What makes HCG particularly distinctive as a research compound is that it produces its steroidogenic effects by acting directly at the gonadal level, bypassing the hypothalamic-pituitary feedback loop entirely. This allows researchers to study isolated gonadal steroidogenesis independent of upstream regulatory signals.

Research Applications

HCG is used in studies examining:

• Leydig cell steroidogenesis and intratesticular testosterone production dynamics
• HPG axis suppression and reactivation, including post-TRT and post-AAS recovery models
• Gonadotropin signaling pathway comparisons (LH vs. HCG downstream effects)
• Hypogonadotropic hypogonadism models and pharmacological restoration of testosterone output
• Spermatogenesis preservation under conditions of gonadotropin suppression
• Ovulation induction and follicular maturation in female reproductive research
• Dose-response relationships between IU dosing and serum testosterone elevation
• Tumor marker dynamics — HCG as a biomarker in germ cell tumor research models

Specifications

Reconstitution

HCG arrives as lyophilized powder and must be reconstituted with bacteriostatic water prior to use. Unlike mg-dosed peptides, HCG is measured in International Units (IU). Use the formula:

Total IU ÷ Volume added (mL) = Concentration (IU/mL)

Example: 5,000 IU vial + 2mL BAC water = 2,500 IU/mL solution Example: 10,000 IU vial + 2mL BAC water = 5,000 IU/mL solution

Add bacteriostatic water slowly by angling the needle against the inside wall of the vial — do not inject directly onto the powder. Gently swirl to dissolve; do not shake, as HCG is a fragile glycoprotein hormone and agitation can compromise biological activity. Reconstituted HCG should be stored at 2–8°C and used within 60 days.

Protocol Notes

HCG is administered subcutaneously or intramuscularly in research protocols, with dosing expressed in IU. Due to its extended half-life relative to endogenous LH, it is typically administered on an every-other-day or twice/three-times-weekly schedule rather than daily.

Typical research dosing framework:

• Maintenance/low-dose range: 250–500 IU every other day or 2–3× weekly
• Mid-range protocols: 1,000–2,000 IU 2–3× weekly
• High-dose/stimulation protocols: 2,500–5,000 IU per administration (used in acute stimulation or HPG axis reactivation studies)
• Frequency: 2–3 administrations per week
• Study duration: 8–16 weeks depending on endpoint (testosterone response, spermatogenesis, HPG axis recovery)

Commonly observed effects in research models:

• Endocrine: Elevated intratesticular and serum testosterone; elevated estradiol via aromatization at higher doses
• Gonadal: Testicular volume maintenance or increase in hypogonadotropic models; luteal progesterone support in female models
• Injection site: Mild redness or transient irritation — generally self-resolving
• Other: Fluid retention, gynecomastia risk at sustained high doses due to estradiol elevation; headache reported anecdotally

Research Stacks

HCG is commonly paired in research settings with:

• HMG — HMG provides FSH-like activity that complements HCG’s LH-like signaling; combined protocols are studied for coordinated gonadotropin-axis stimulation in models of hypogonadotropic hypogonadism.
• Kisspeptin-10 — Kisspeptin acts upstream at the hypothalamic level to drive GnRH pulsatility, while HCG acts downstream at the gonadal level; pairing allows researchers to probe the full HPG axis at multiple nodes simultaneously.
• PT-141 — PT-141 (bremelanotide) engages melanocortin receptors independently of the gonadotropin axis; co-administration studies examine whether central melanocortin signaling and peripheral LH-analog activity produce additive effects in sexual function research models.

Purity Guarantee

Every batch is ≥99% purity. If you independently test your compound and the results don’t match — send us the COA and we’ll issue store credit, no questions asked.