HCG (5000 IU)

Human Chorionic Gonadotropin – Glycoprotein Hormone / LH Receptor Agonist

Human Chorionic Gonadotropin (HCG) is a naturally occurring glycoprotein hormone composed of α- and β-subunits, structurally similar to luteinizing hormone (LH). HCG binds with high affinity to the LH/CG receptor (LHCGR), triggering signaling pathways that regulate steroidogenesis, gonadal development, testicular function, and reproductive endocrinology.

In research contexts, HCG is widely used as a biological LH analog to study:

• Leydig cell steroidogenesis

• Testosterone biosynthesis and endocrine feedback

• Spermatogenesis and gonadal axis recovery

• Ovarian follicular maturation and ovulatory signaling

• Placental and embryonic developmental pathways

HCG supplied as 5000 IU lyophilized powder is intended strictly for laboratory and experimental use outside of regulated clinical environments.

Specifications

Synonyms: Human Chorionic Gonadotropin, hCG, gonadotrophin, chorionic gonadotropin
Structure: Heterodimeric glycoprotein hormone (α + β subunits), ~36–40 kDa
Molecular Weight: ~36,700–40,000 Da (glycosylation-dependent)
Class: LH receptor (LHCGR) agonist / gonadotropin
Potency: 5000 IU per vial (research grade)
Presentation: Lyophilized sterile powder, reconstitutable with aqueous buffer

Mechanism of Action and Endocrine Pathways

1. LH/CG Receptor Activation

HCG binds to and activates LHCGR, a G-protein coupled receptor expressed in:

• Leydig cells (testes)

• Theca and granulosa cells (ovaries)

• Placental tissue

• Adrenal and extragonadal sites (in research models)

Receptor activation increases:

• cAMP

• Protein kinase A (PKA) signaling

• Steroidogenic acute regulatory protein (StAR) expression

• Cholesterol transport into mitochondria (rate-limiting step of steroidogenesis)

2. Steroidogenesis

In testicular models, HCG reliably stimulates:

• Testosterone synthesis

• Upregulation of 17β-hydroxysteroid dehydrogenase

• Enhanced DHEA → androstenedione → testosterone pathway flux

In ovarian models, HCG promotes:

• Progesterone production

• Luteinization processes

• Follicular maturation and ovulatory signaling

3. Regulation of Gonadal Development & Spermatogenesis

Through LH-like signaling, HCG research demonstrates:

• Maintenance of intratesticular testosterone (ITT)

• Support of Sertoli cell function

• Rescue of spermatogenesis in suppressed or immature gonads

• Restoration of steroidogenic gene expression following hypothalamic-pituitary suppression models

4. Placental and Embryonic Research Models

HCG is a key regulator in:

• Implantation

• Trophoblast differentiation

• Angiogenesis in early pregnancy

• Immune-modulatory effects at the maternal–fetal interface

Research Applications

1. Endocrine and reproductive biology

HCG is used to model:

• LH deficiency

• Hypogonadotropic hypogonadism

• Pituitary suppression (GnRH analog models)

• Leydig cell test function

• Testicular axis recovery following anabolic suppression

2. Male reproductive function

Studies show HCG:

• Increases intratesticular testosterone, essential for spermatogenesis

• Stimulates sperm production after hormonal suppression

• Reverses testicular atrophy in specific experimental paradigms

3. Female reproductive signaling

In ovarian research, HCG:

• Mimics the LH surge

• Induces oocyte maturation

• Triggers ovulatory cascade

• Regulates luteal-phase progesterone production

4. Metabolic and genetic research

HCG influences:

• Steroidogenic gene transcription

• Mitochondrial cholesterol import

• Trophoblast invasion and angiogenesis

• Modulation of inflammatory pathways in reproductive tissues

Safety, Limitations, and Regulatory Notes

• HCG is clinically approved for select fertility and endocrine conditions, but research-grade HCG is not approved for human use.

• Physiologic actions depend strongly on dose, timing, and endocrine context.

• Known clinical adverse effects (contextual): gynecomastia, fluid retention, mood changes, increased estradiol, injection-site irritation.

• Should not be used for weight loss, bodybuilding protocols, or unregulated hormone manipulation.

Research-only HCG should be handled by qualified laboratory personnel under appropriate biosafety procedures.

Research Use Only – Important Notice

This HCG (5000 IU) product is supplied exclusively for laboratory research.

• Not for human or veterinary use

• Not for therapeutic, cosmetic, fertility, bodybuilding, or diagnostic application

• Intended only for in vitro work or controlled animal studies

• All descriptions summarize findings from preclinical and clinical endocrinology literature

• Not to be interpreted as dosing guidance or medical advice

References (Non-Wikipedia, peer-reviewed, with links)

1. Ascoli M, Fanelli F, Segaloff DL. The LH/CG receptor. Endocr Rev.
   https://pubmed.ncbi.nlm.nih.gov/11399741/

Santen RJ, Bardin CW. Reproductive effects of LH and hCG. Endocrinology.
https://pubmed.ncbi.nlm.nih.gov/4343955/

Roth MY et al. HCG maintains intratesticular testosterone in gonadotropin-suppressed men. J Clin Endocrinol Metab.
https://pubmed.ncbi.nlm.nih.gov/16608890/

Liu L, Wang J et al. HCG regulation of steroidogenic gene expression. Mol Cell Endocrinol.
https://pubmed.ncbi.nlm.nih.gov/21756939/

Licht P et al. Role of hCG in implantation and early pregnancy. Mol Cell Endocrinol.
https://pubmed.ncbi.nlm.nih.gov/11000331/

Liu X et al. Effects of hCG on trophoblast differentiation and invasion. Reproduction.
https://pubmed.ncbi.nlm.nih.gov/25623731/

Egarter C et al. HCG modulation of ovarian steroidogenesis. Fertil Steril.
https://pubmed.ncbi.nlm.nih.gov/2528492/

Hayes FJ et al. Testicular function models using hCG stimulation. J Clin Endocrinol Metab.
https://pubmed.ncbi.nlm.nih.gov/10634382/