HCG

HCG (Human Chorionic Gonadotropin) | Buy HCG CHINA | Research-Grade Gonadotropin | Research Use Only

HCG (Human Chorionic Gonadotropin) is a naturally occurring glycoprotein hormone produced by the trophoblast cells of the early embryo and, later, the placenta — and one of the most extensively studied gonadotropins in reproductive biology, Leydig cell function, HPG axis research, and embryo implantation science. It is studied in laboratory research for its potent activation of the LHCGR receptor, its role in steroidogenesis and testosterone synthesis, trophoblast invasion, early pregnancy signalling, and biased agonism at the LH/CG receptor — available to buy in the CHINA from Sino Research Peptide Manufacturer in high-purity lyophilised form, >99% HPLC-verified purity, with batch-specific COA and fast CHINA dispatch for laboratory and in vitro research use only.

Distributed by Peptides Lab UK in a high-purity lyophilised format, for laboratory research use only. This compound is handled in controlled settings for in vitro and pre-clinical studies, with no applications in human or veterinary medicine. Each batch undergoes rigorous quality analysis to ensure >99% purity (HPLC verified).

What Is HCG?

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) are integral components of the hypothalamic–pituitary–gonadal axis, which controls sexual maturation and functionality. Although they share a high degree of homology, the physiologic roles of these hormones are unique, governed by differences in expression pattern, biopotency, and regulation — with LH serving as a key regulator of gonadal steroidogenesis and ovulation, and hCG predominantly active in pregnancy and fetal development.

HCG is a heterodimeric glycoprotein composed of an α-subunit — identical to that of LH, FSH, and TSH — and a unique β-subunit. The β-subunit of hCG has a highly glycosylated 24-amino acid C-terminal tail absent from LH, which increases receptor activity and slows metabolic clearance — resulting in a half-life of approximately 36 hours for hCG compared to just 30 minutes for LH, making hCG an extended-duration pharmacological analogue of LH for receptor biology research.

HCG represents one of the first molecular messages sent by the pre-implanting embryo to modulate the implantation site and ensure timely initiation of the nidation process. Active secretion begins at the blastocyst stage, enabling hCG detection in the maternal circulation approximately 10 days after fertilisation, with the highest values reached between the 10th and 11th week of pregnancy before declining through the remainder of the first trimester.

As a research compound, HCG UK is one of the most broadly studied and well-characterised gonadotropins in the scientific literature, with published research spanning Leydig cell biology, HPG axis signalling, trophoblast invasion, immune modulation, and biased receptor agonism.

How Does HCG Work?

HCG functions as a high-affinity agonist of the LH/CG receptor (LHCGR) — a G protein-coupled receptor expressed primarily in Leydig cells of the testis, granulosa cells of the ovary, and trophoblast cells of the developing placenta. Despite sharing a receptor with LH, emerging research has established that hCG and LH are not equivalent in their intracellular signalling profiles.

LHCGR Binding and Biased Agonism

Research using BRET and FRET technologies in living cells confirmed that hCG and LH differentially promote cell responses mediated by the LHCGR — revealing divergences in potency, efficacy, and kinetics. Recombinant hCG was found to be more potent than LH in both HEK293 and mouse Leydig tumour cells, demonstrating that LH and hCG display biased agonism at their shared receptor.

cAMP/PKA Steroidogenic Signalling

In primary mouse Leydig cell cultures, hCG was found to be approximately 10-fold more potent than LH in cAMP recruitment, and slightly but significantly more potent in cAMP-dependent Erk1/2 phosphorylation — though no significant differences were observed at the level of downstream steroidogenic events including Creb phosphorylation, Stard1 gene expression, and testosterone synthesis.

Leydig Cell Testosterone Synthesis

Testicular Leydig cells are highly responsive to LH and its analogue hCG via the LH/hCG receptor on the plasma membrane. HCG derivatives have been shown to bind to these receptors with different affinities than native hCG and to modulate testosterone production — findings relevant to understanding the pharmacology of LHCGR activation in steroidogenesis research.

HPG Axis Signalling and Spermatogenesis Research

Luteinizing hormone-driven testosterone is central to spermatogenesis, with LH acting on Leydig cells to stimulate steroid production and intratesticular testosterone binding to androgen receptors on Sertoli cells — influencing gene transcription and paracrine signalling required for germ cell development. Due to their similar structures, both hCG and LH bind to the same LHCGR receptor on Leydig cells, but hCG does so with greater affinity, preferentially inducing cAMP and increasing intracellular Ca²⁺, upregulating genes that code steroidogenic enzymes.

Trophoblast Invasion and Endometrial Remodelling

HCG is one of the earliest embryo-derived secreted signals in the endometrium, which abundantly expresses hCG receptors. In vitro research has demonstrated that hCG decreases TIMP-1 secretion in endometrial stromal cells, thereby facilitating extravillous trophoblast invasion — with MMP-2 levels increasing and gelatine zymography confirming increased MMP-2 activity following hCG treatment.

Immune Modulation at the Maternal-Fetal Interface

Research has demonstrated that hCG modulates immune responses at the maternal-fetal interface through epigenetic mechanisms — specifically, hCG inhibits CXCL10 expression in human endometrial stromal cells by enhancing EZH2 expression and inducing H3K27me3 histone methylation at the CXCL10 promoter, thereby suppressing T cell recruitment to the implantation site.

What Does HCG Do in Research?

In laboratory and pre-clinical settings, hCG has been studied across an exceptionally broad range of biological systems. Research has examined its role in:

• LHCGR receptor binding, biased agonism, and intracellular cAMP/PKA signalling studies
• Leydig cell steroidogenesis and testosterone synthesis pathway research
• HPG axis regulation and gonadotropin interaction studies in male and female models
• Spermatogenesis, intratesticular testosterone, and male fertility biology research
• Trophoblast invasion, placentation, and endometrial ECM remodelling investigations
• Embryo implantation and the embryo-endometrial microenvironment
• Immune modulation at the maternal-fetal interface — regulatory T cells, NK cells, dendritic cells
• Hyperglycosylated hCG (hCG-H) isoform biology and early pregnancy signalling
• VEGF-driven angiogenesis and corpus luteum rescue pathway research
• Comparative LH vs hCG biased agonism and receptor signalling kinetics studies

HCG and Corpus Luteum Research

Research has shown that rising systemic hCG levels cause a very rapid elevation of serum progesterone, reflecting rescue of the corpus luteum — one of hCG’s primary endocrine functions. Beyond this, hCG has been shown to stimulate VEGF production significantly in endometrial tissue, suggesting a role in the control of endometrial vascularisation and placentation.

HCG and Hyperglycosylated Isoform Research

Hyperglycosylated hCG (hCG-H) is an over-glycosylated isoform of hCG that comprises up to 90% of total hCG measurable in serum and urine during the first 2–3 weeks of pregnancy when invasive trophoblast activity is at its highest — dropping to less than 5% of total hCG by the end of the first trimester. Functionally, hCG-H has been found to promote trophoblast invasion during early pregnancy and may play roles in immune cell modulation and endothelial function within the uterus.

HCG and Immune Cell Modulation Research

Research has confirmed that hCG not only regulates local immune cell numbers at the implantation site but also drives these cells to adopt a unique phenotype with the aim to support and protect the developing fetus — findings that have informed research into hCG’s role in idiopathic infertility, recurrent miscarriage, and immunological tolerance of the semi-allogeneic embryo.

HCG and Male Reproductive Research

Research has confirmed the utility of hCG in pre-clinical models of male hypogonadism driven by impaired HPG axis signalling — including conditions where exogenous hormone exposure has suppressed pulsatile GnRH and LH secretion, reducing Leydig cell testosterone output and intratesticular testosterone levels. These models have used hCG as a direct LHCGR agonist to study HPG axis research applications and spermatogenesis restoration.

What Do Studies Say About HCG?

HCG has one of the most extensive and diverse published research profiles of any naturally occurring hormone, with peer-reviewed literature spanning reproductive endocrinology, developmental biology, immunology, and clinical research.

HCG and LH: Not Equivalent in Signalling

A landmark review in Endocrine Reviews concluded that the long-assumed equivalence of LH and hCG has been disproved by accumulating in vitro and clinical evidence, highlighting their sex-specific functions. HCG displays notably greater cAMP/PKA-mediated steroidogenic and pro-apoptotic potential compared to LH, and Leydig cell in vitro exposure to hCG results in qualitatively similar but quantitatively distinct cAMP/PKA and pERK1/2 activation patterns.

HCG and Fetal Leydig Cell Development Research

Research has confirmed that hCG plays a larger role than fetal pituitary LH in testosterone production by Leydig cells during early fetal development, with the LHCGR not detected in fetal Leydig cells until 10–12 weeks after conception. Testosterone produced in response to hCG is responsible for virilisation of the reproductive tract and promotion of the ductus deferens, epididymides, seminal vesicles, and ejaculatory ducts.

HCG and Trophoblast Invasion Research

Research has confirmed that first-trimester human trophoblastic cells — specifically extravillous cytotrophoblasts (CTBs) — both express hCG/LH receptors and present an invasive phenotype, establishing an autocrine/paracrine role for hCG in regulating the trophoblast invasion that is essential for blastocyst implantation and subsequent placentation.

HCG Isoforms and Pregnancy Complication Research

Altered levels of hyperglycosylated hCG are characteristic of pregnancy complications associated with aberrant trophoblast function and inadequate placentation — including pre-eclampsia and Down’s syndrome — making hCG isoform research a significant area of inquiry in obstetric risk prediction and early pregnancy monitoring.

Key cited studies:

• Cole LA (2012) — hCG, Five Independent Molecules — Clin Chim Acta 413(1–2):48–65. PubMed ID: 21982680
• Casarini L et al. (2017) — Human LH and hCG Stimulate Differently the Early Signalling Pathways but Result in Equal Testosterone Synthesis in Mouse Leydig Cells in Vitro — Reprod Biol Endocrinol 15(1):2. PMC5217336
• Casarini L et al. (2017) — Human Luteinizing Hormone and Chorionic Gonadotropin Display Biased Agonism at the LH and LH/CG Receptors — Sci Rep 7:940. DOI: 10.1038/s41598-017-01078-8
• Casarini L & Simoni M (2018) — Two Hormones for One Receptor: Evolution, Biochemistry, Actions and Pathophysiology of LH and hCG — Endocr Rev 39(5):549–592. DOI: 10.1210/er.2018-00065
• Schumacher A et al. (2019) — HCG-Mediated Immune Responses That Facilitate Embryo Implantation and Placentation — Front Immunol 10:2896. PMC6914810
• Boehm U et al. (2020) — HCG Modulates CXCL10 Expression Through Histone Methylation in Human Decidua — PubMed ID: 32238853
• Evans J (2016) — Hyperglycosylated hCG: A Unique Human Implantation and Invasion Factor — Am J Reprod Immunol 75(3):333–40. PubMed ID: 26676718
• Esteves SC et al. (2025) — HCG-Based Clinical Treatments for Infertile Men with Non-Obstructive Azoospermia — Andrology. DOI: 10.1111/andr.70003