Overview
Overview
Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone that mimics luteinizing hormone (LH) by binding to LH receptors in the gonads[1]. With a 36‑hour half‑life (compared to LH’s 30 minutes), HCG provides sustained stimulation of testosterone production in men and ovulation induction in women[2]. This educational protocol presents a practical three‑times‑weekly subcutaneous approach for maintaining testicular function and fertility. Reconstitute: Add 2.0 mL bacteriostatic water → 2,500 I
- Category
- Fertility
- Routes
- subcutaneous
Mechanism
HCG
Mechanism of action
Mechanism of action
HCG is a glycoprotein hormone structurally similar to luteinizing hormone (LH). It binds to the same LH receptors in testicular Leydig cells, stimulating endogenous testosterone production [1] . Unlike endogenous LH (which has a 30‑minute half‑life), HCG’s extended 36‑hour half‑life provides sustained gonadal stimulation [2] . This makes it effective for maintaining testicular function during exogenous testosterone therapy, where natural LH production is suppressed. Studies show that low‑dose HCG (250–500 IU every other day) maintains intratesticular testosterone at near‑baseline levels in men receiving testosterone therapy [4] . Higher doses (1,500–5,000 IU multiple times weekly) are used to restore spermatogenesis and endogenous testosterone production in cases of hypogonadotropic hypogonadism or post‑anabolic steroid recovery [5] [6] .
Key research findings
- 01
Heterodimeric glycoprotein hormone composed of a common alpha subunit (shared with LH, FSH, and TSH) plus a hormone-specific beta subunit; structure is well characterized (established biochemistry).
- 02
Activates the LH/choriogonadotropin receptor (LHCGR) - the same receptor as luteinizing hormone - so research commonly uses it as an LH surrogate (established pharmacology / in vitro).
- 03
The beta-subunit C-terminal extension and heavy glycosylation give hCG a substantially longer circulating half-life than LH, a property exploited in engineered long-acting gonadotropins (established biochemistry / human study).
- 04
Its LH-like action on testicular Leydig cells (steroidogenesis/testosterone production) and on ovarian function is extensively characterized in reproductive-endocrinology research (human study / animal model).
- 05
Naturally produced by placental syncytiotrophoblast tissue during pregnancy; detection of its beta subunit is the basis of pregnancy testing (established physiology).
Primary source: hCG has a deep, mature research base spanning biochemistry, animal models, and human reproductive-endocrinology studies, with its LH-receptor activity and long half-life among the best-characterized features. On this platform it is handled strictly as a research material rather than a therapy.
Pharmacokinetic profile
Single-dose plasma curve over 24h. Shaded band = commonly-cited therapeutic window. Illustrative only.
Protocol Reference
Protocol reference
Commonly cited research range: 500–2500 mcg, daily_for_cycles.
Reference figures reported in the research literature — not a dosing recommendation. For interactive vial math and scheduling, see the Calculator and Schedule tabs.
Cited protocol & reconstitution guide
Source-backed reference fields by phase, including any volume fields authored in the cited guide.
Weeks 1–12
500 IU
| Phase | Reference amount | Units / volume |
|---|---|---|
| Weeks 1–12 | 500 IU | 20 units (0.20 mL) |
Storage & Handling
Storage requirements(typical for most peptides)
Can be stored for extended periods. Protect from moisture.
Store in refrigerator door. Never freeze after reconstitution.
Label vials with reconstitution date. Discard if cloudy.
Reconstitution steps
- 01🌡️Draw 2.0 mL bacteriostatic water with a sterile syringe.
- 02🧴Inject slowly down the vial wall; avoid foaming or vigorous shaking.
- 03💉Gently swirl or roll until the powder fully dissolves (clear solution).
- 04💧Label vial with reconstitution date and concentration (2,500 IU/mL); refrigerate immediately at 2–8 °C (35.6–46.4 °F).
- 05🔄Dosing Calculations:
- 06🏷️250 IU = 10 units (0.10 mL)
- 07❄️500 IU = 20 units (0.20 mL)
- 08💉1,000 IU = 40 units (0.40 mL)
- 09💉High‑Dose Protocol (for Post‑Cycle Recovery or Severe Suppression)
- 10💉WEEK/PHASE DOSE PER INJECTION (IU) UNITS (PER INJECTION) (ML)
- 11💉Weeks 1–4 1,500 IU 60 units (0.60 mL)
- 12💉Weeks 5–8 2,000 IU 80 units (0.80 mL)
- 13💉Weeks 9–12 1,000 IU 40 units (0.40 mL)
- 14💉Frequency: Inject 3 times weekly subcutaneously. High‑dose protocols (1,500–2,500 IU per injection) are used to reactivate testosterone production after prolonged anabolic steroid use or severe hypogonadotropic hypogonadism[5][6]. After initial recovery, doses are typically reduced to maintenance levels (500–1,000 IU 3×/week).
- 15💉Important: This guide is for educational purposes only and is not medical advice. For research use only. Not for human consumption.
Additional storage notes
Refrigerate at 2–8 °C (35.6–46.4 °F) . Can be stored at room temperature but refrigeration is preferred for long‑term storage [8] .
Must be refrigerated at 2–8 °C (35.6–46.4 °F) . Stable for up to 60 days when using bacteriostatic water [9] .
Do NOT freeze reconstituted HCG; freezing denatures the protein [9] .
Store in original packaging or light‑protected container; minimize light exposure.
Label vial with reconstitution date; discard after 60 days or if cloudiness/particles appear.
Clinical Evidence
Clinical evidence
Extensively characterized in reproductive-endocrinology research for its LH-like activity on testicular and ovarian function.
hCG has a deep, mature research base spanning biochemistry, animal models, and human reproductive-endocrinology studies, with its LH-receptor activity and long half-life among the best-characterized features. On this platform it is handled strictly as a research material rather than a therapy.
- 01Heterodimeric glycoprotein hormone composed of a common alpha subunit (shared with LH, FSH, and TSH) plus a hormone-specific beta subunit; structure is well characterized (established biochemistry).
- 02Activates the LH/choriogonadotropin receptor (LHCGR) - the same receptor as luteinizing hormone - so research commonly uses it as an LH surrogate (established pharmacology / in vitro).
- 03The beta-subunit C-terminal extension and heavy glycosylation give hCG a substantially longer circulating half-life than LH, a property exploited in engineered long-acting gonadotropins (established biochemistry / human study).
- 04Its LH-like action on testicular Leydig cells (steroidogenesis/testosterone production) and on ovarian function is extensively characterized in reproductive-endocrinology research (human study / animal model).
- 05Naturally produced by placental syncytiotrophoblast tissue during pregnancy; detection of its beta subunit is the basis of pregnancy testing (established physiology).
Evidence maturity varies by compound; much peptide research is preclinical (in vitro or animal-model). Where human data are limited, findings should be read as research observations, not clinical conclusions.
References
Literature references
Published research articles and sources related to HCG.
- 01National Center for Biotechnology Information (NCBI) — Human Chorionic Gonadotropin: structure, function, and LH receptor binding mechanisms View Source
- 02Seminars in Reproductive Medicine — Pharmacokinetics and pharmacodynamics of HCG: extended half‑life and sustained activity View Source
- 03Translational Andrology and Urology (2018) — Lee JA & Ramasamy R: Review of hCG for hypogonadal male infertility (typical regimens: 1,500–5,000 IU 2–3×/week) View Sourceet al. (2018)
- 04The Journal of Clinical Endocrinology & Metabolism (2005) — Coviello AD et al: Low‑dose hCG maintains intratesticular testosterone in men with testosterone‑induced gonadotropin suppression View Sourceet al. (2005)
- 05Male Infertility Guide — Clinical commentary on hCG dosing: 500 IU SC 3×/week for maintenance; 1,000–4,000 IU 3×/week for post‑androgen recovery View Source
- 06Drugs.com (2025) — HCG Dosage Guide: Adult dose for male hypogonadism: 500–1,000 IU IM 3×/week for 3 weeks, then 2×/week; or 4,000 IU 3×/week for 6–9 months View Sourceet al. (2025)
- 07Mayo Clinic — Chorionic Gonadotropin drug description: uses for ovulation induction, sperm production, and cryptorchidism treatment View Source
- 08University Hospitals Fertility Center — Patient instructions for low‑dose HCG: storage at room temperature (unreconstituted); refrigeration after mixing View Source
- 09FDA Prescribing Information — Chorionic Gonadotropin (Pregnyl/Novarel): reconstituted solution stable for 60 days when refrigerated; do not freeze View Source
- 10University Hospitals Fertility Center — SC injection technique for HCG: clean site, pinch skin, insert straight in, inject slowly, wait before removing needle; never reuse syringes View Source
- 11Healthline (2019) — How to Inject hCG: step‑by‑step SC and IM injection instructions for fertility and hormone therapy applications View Sourceet al. (2019)
- 12Centers for Disease Control and Prevention (CDC) — Vaccine administration guidelines: subcutaneous injection technique (45–90° angle, no aspiration required) View Source
- 13NCBI Bookshelf — Best practices for medication injection: aseptic technique, preparation, and safe administration procedures View Source
- 14British Journal of Clinical Pharmacology (1995) — Lijesen GK et al: Meta‑analysis concluding no scientific evidence supports HCG for weight loss (obesity diet context) View Sourceet al. (1995)
- 15Pure Lab Peptides — HCG 5000 IU product page: high‑purity research‑grade HCG with third‑party testing and COA documentation View Source
Research Considerations
Research considerations
Research Use Only - not for human or veterinary therapeutic use. Has been studied in clinical research; on this platform it is handled strictly as a research material. Consult a licensed healthcare professional for any clinical decisions.
Factors noted in the research literature; not patient-specific medical advice.
Regulatory Status
Regulatory status
RUO
Comparisons
Comparisons
| Compound | Mechanism | Route | Status |
|---|---|---|---|
| HCGthis | A glycoprotein hormone that binds LH receptors in the gonads, mimicking luteinizing hormone with a substantially longer half-life to stimulate gonadal steroidogenesis. | subcutaneous | Investigational / RUO |
| HMG | A purified gonadotropin preparation providing combined FSH and LH activity, acting on gonadal receptors to support gametogenesis and steroidogenesis. | subcutaneous | Investigational / RUO |
| Oxytocin | A nonapeptide hormone acting on oxytocin receptors; studied for roles in uterine contraction, lactation, and central modulation of social and affiliative behavior. | subcutaneous | Investigational / RUO |
| Gonadorelin | A synthetic form of gonadotropin-releasing hormone (GnRH) acting on pituitary GnRH receptors to stimulate luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release, supporting the hypothalamic-pituitary-gonadal axis. | subcutaneous | Investigational / RUO |
| HGH 191AA | Recombinant human growth hormone (somatropin), a 191-amino-acid protein identical to endogenous GH, acting on GH receptors to drive IGF-1 production and influence growth, metabolism, and tissue repair. | subcutaneous | Investigational / RUO |
| IGF-1 LR3 | A modified analog of insulin-like growth factor-1 with reduced binding to IGF-binding proteins, giving a markedly extended half-life and prolonged activation of IGF-1 receptor anabolic signaling. | subcutaneous | Investigational / RUO |
| Ipamorelin | Binds to ghrelin receptors to stimulate pituitary gland to release growth hormone. Highly selective with minimal side effects. | subcutaneous | Investigational / RUO |
Attributes shown for research comparison only; not a statement of efficacy or therapeutic equivalence.
FAQ
Frequently asked questions
Identity - human chorionic gonadotropin, a glycoprotein hormone naturally produced by placental (syncytiotrophoblast) tissue during pregnancy. It consists of an alpha subunit shared with several pituitary hormones and a distinct beta subunit.
Mechanism - it activates the LH/CG receptor (LHCGR), the same receptor as luteinizing hormone. Because of this, research often uses it as a longer-acting stand-in for LH to study gonadal (testicular and ovarian) function.
Identity/biochemistry - pregnancy tests detect the beta subunit of hCG. This is a property of the molecule itself, not a claim about the research compound as handled on this platform.
Research status - hCG is one of the most extensively characterized reproductive hormones, with a large literature across biochemistry, animal, and human studies. Here it is handled only as a research material.
This platform does not provide human dosing guidance. Research-reported amounts vary by study design; see the protocol/reconstitution reference for calculation support only. This is not medical advice.
Handling/storage - practices vary by supplier and formulation. Lyophilized material is generally kept cold and protected from light, and reconstituted material is refrigerated and used within a limited window. Follow the supplier's documentation and certificate of analysis.
Regulatory - Research Use Only; not offered for human or veterinary therapeutic use. Consult a licensed healthcare professional for any clinical decisions.
Research-use notice
Research Use Only. This educational content and calculation support is intended for private research documentation. It does not provide medical advice, human-use directions, or claims of safety or effectiveness.