HCG (Human Chorionic Gonadotropin)

What is it?

A glycoprotein hormone originally isolated from the placenta. HCG mimics LH at the testicular Leydig-cell receptor — it’s the LH analog that stimulates testosterone production directly at the testes, bypassing the hypothalamus and pituitary entirely. Long historical clinical use including pediatric undescended-testis treatment, fertility, and as a “rescue” for TRT users to keep testicular volume and intratesticular testosterone (which is critical for spermatogenesis) online.

What does it do in my body?

• Binds the LH receptor on Leydig cells.
• Activates the cAMP / steroidogenesis pathway → testosterone production.
• Maintains testicular volume and intratesticular testosterone — which is why TRT users add HCG to preserve fertility and prevent the testicular atrophy that comes with full HPG suppression.

How can it help me?

• Best fit: Keeping testicular function online despite upstream suppression (e.g., on TRT) or preventing testicular atrophy
• Where the science stands: Long clinical use, well-characterized mechanism and outcomes; TRT-adjuvant use is the most common modern indication

The full evidence — every human, animal, and lab study, graded — is one tap away: use the See the deeper science → toggle at the top.

Is it dangerous? What are the side effects?

• Generally well-tolerated at TRT-adjuvant doses.
• Higher-dose HCG can drive significant estradiol via Leydig-cell-localized aromatase — monitoring estradiol is part of the protocol.
• Gynecomastia risk if estradiol rises uncontrolled.

Regulatory status: HCG sits on a real prescription/clinical pathway, not the typical research-chem lane most peptides on this site occupy. It is FDA-approved historically for several indications, and licensed clinicians prescribe it routinely. What has cycled repeatedly is compounding-pharmacy access specifically — regulatory pressure has targeted compounding pharmacies producing HCG multiple times, with the access landscape moving back and forth between brand-name-only and compounded availability. Per clinical experience relayed in the source material: brand-name and compounding-pharmacy HCG are made the same way, with no meaningful quality difference between them — the repeated access restrictions read as a commercial/market-protection dynamic rather than a safety-driven one.

That framing matters for how to read “is compounded HCG legitimate” honestly: verified compounders (with third-party COAs) produce a product that is clinically equivalent to brand-name; unverified gray-market compounders are a separate and real risk category. Collapsing both into one “compounded is scary” bucket is inaccurate.

Banned by WADA for sport (S2 — peptide hormones, growth factors). Historical precedent suggests compounded access cycles back over time, though the exact current status should be verified before any customer-facing claim.

Part 1 — How to reconstitute it

What's used: bacteriostatic water (sterile, preserved water the powder is mixed with) and a separate, larger reconstitution syringe used only for mixing — not the small syringe used for administration.

The exact bacteriostatic-water volume and resulting concentration for HCG (Human Chorionic Gonadotropin) are covered in the dosing notes and the deeper-science view. The right volume depends on the vial size.

How it's mixed

• The vial is tilted and the bacteriostatic water is added slowly down the inside glass wall — not squirted straight onto the powder.
• It is swirled gently to dissolve. It is never shaken — shaking can damage the peptide.
• The reconstituted vial is stored refrigerated and out of light.
• Reconstituted peptides are commonly used within a few weeks, inside the beyond-use window the source specifies — that window varies by peptide.

The free reconstitution calculator does the concentration math for any vial size and water volume, including the equivalent units on an insulin syringe.

Part 2 — Typical dosing

Educational context only — talk to a licensed medical provider before any protocol. What follows describes the doses and schedules most commonly reported in the research and by practitioners, shared so you can have an informed conversation. These compounds are sold for research use only, are not FDA-approved drugs, and this is not medical advice.

Administration as reported. Reported practice is subcutaneous administration (into the fat just under the skin) using a 0.3 mL U-100 insulin syringe, with sites rotated.

• TRT-adjuvant dose (community-typical): 250–500 IU SubQ, 2–3×/week.
• Reconstitution: HCG vials are dosed in international units (IU), not mg — reconstitution depends on vial strength (commonly 5,000 or 10,000 IU per vial) and the amount of bacteriostatic water used. Verify with the specific product.
• Route: subcutaneous injection.
• Cycle: continuous co-administration with TRT is the most common pattern; standalone HCG monotherapy is used less often.

Turning milligrams into syringe units. On a U-100 syringe, 100 units = 1 mL, so 1 unit = 0.01 mL. At a concentration of C mg/mL, a dose of D mg = D ÷ C mL = (D ÷ C) × 100 units. Example: at 5 mg/mL, a 0.5 mg dose = 0.1 mL = 10 units. The exact units depend on the vial's mg and the water volume used.

What should I avoid combining — and what's synergistic?

HCG (Human Chorionic Gonadotropin) doesn't have a dedicated stacking protocol in our notes — the interactions that matter most are in the safety section above. For how people combine it with other peptides, the deeper-science view has the full detail.

Where do people source this?