HCG Ireland | Buy Research-Grade Human Chorionic Gonadotropin | Verified Biological Activity

HCG (Human Chorionic Gonadotropin) is a recombinant glycoprotein hormone and one of the most extensively studied gonadotropin research compounds available to laboratories in Ireland — a heterodimeric glycoprotein produced physiologically by syncytiotrophoblast cells of the developing placenta that acts on luteinising hormone receptors (LH/hCG receptor) in gonadal and extragonadal tissues to drive steroidogenesis, gametogenesis support, and a remarkably broad range of biological processes beyond classical reproductive biology, making it a critical research tool for studying LH receptor pharmacology, testicular and ovarian steroidogenesis mechanisms, reproductive endocrinology, Leydig cell biology, and the expanding non-reproductive biology of LH/hCG receptor signalling in thyroid, adrenal, brain, and immune tissue contexts. Researchers and institutions across Ireland can source verified, research-grade HCG directly from our Irish peptide and hormone supply, with domestic-speed dispatch and complete batch documentation.

✅ Verified Biological Activity — IU-Standardised

✅ Batch-Specific Certificate of Analysis (CoA) Included

✅ Recombinant Glycoprotein | GMP Manufactured

✅ Fast Dispatch to Ireland | Peptides Ireland Stock

What Is HCG?

Human Chorionic Gonadotropin is a heterodimeric glycoprotein hormone — consisting of a non-covalently associated alpha subunit shared with LH, FSH, and TSH, and a unique beta subunit that confers HCG’s receptor specificity and biological identity — produced in large quantities by placental syncytiotrophoblast cells during pregnancy, where it serves as the primary hormonal signal maintaining corpus luteum progesterone production during early gestation before the placenta assumes direct steroidogenic capacity. HCG is one of the most biologically potent gonadotropins identified — binding the LH/hCG receptor (LHCGR) with high affinity and producing biological responses equivalent to LH across all LH-responsive tissues — but with a dramatically longer circulating half-life than endogenous LH, attributable to its extensive O-linked glycosylation and particularly to the unique C-terminal peptide extension on the HCG beta subunit that carries additional sialic acid-rich O-linked glycans not present on LH.

The LH/hCG receptor — a G-protein coupled receptor of the leucine-rich repeat GPCR subfamily — is expressed on Leydig cells of the testis, granulosa and luteal cells of the ovary, and in a growing list of extragonadal tissues including thyroid follicular cells, adrenal cortex, uterine endometrium and myometrium, placental trophoblasts, brain, kidney, and immune cells. In gonadal tissue, LH/hCG receptor activation drives steroidogenesis through the cAMP/PKA signalling cascade — stimulating cholesterol mobilisation, StAR protein expression, and the enzymatic cascade that converts cholesterol to testosterone in Leydig cells and to progesterone and oestradiol in ovarian cells. This LH/hCG receptor-driven steroidogenesis represents the primary mechanism through which HCG influences gonadal biology and has been the central focus of its research application in reproductive endocrinology and steroidogenesis research.

HCG’s unique C-terminal peptide (CTP) extension — a 24 amino acid sequence on the HCG beta subunit that carries four O-linked glycosylation sites rich in sialic acid residues — is the primary structural basis for its extended half-life compared to LH. The sialic acid residues on this CTP dramatically reduce clearance through hepatic asialoglycoprotein receptors that would otherwise rapidly remove desialylated glycoproteins from circulation — with the combined effect that HCG has a circulating half-life of approximately 24–36 hours compared to LH’s half-life of approximately 20–30 minutes. This half-life difference has made HCG the gonadotropin of choice for research requiring sustained LH receptor activation — providing days-long receptor stimulation from a single administration in pre-clinical models where LH’s short half-life would require impractically frequent dosing.

As a research compound, HCG is standardised and quantified in International Units of biological activity — defined against international reference preparations — rather than by protein mass alone, reflecting the importance of glycosylation in determining HCG’s biological potency and the need for activity-based rather than mass-based standardisation to ensure research reproducibility across batches with potentially varying glycosylation profiles.

What Does HCG Do in Research?

In controlled laboratory and pre-clinical settings, HCG is studied across a range of reproductive endocrinology, steroidogenesis, LH receptor pharmacology, and non-reproductive gonadotropin biology research applications:

LH/hCG Receptor Pharmacology Research — HCG is the primary pharmacological tool for studying LH/hCG receptor biology — with research examining receptor binding kinetics, receptor activation and downstream cAMP/PKA signalling cascade characterisation, receptor internalisation and desensitisation following agonist stimulation, and the molecular mechanisms linking LH/hCG receptor activation to the steroidogenic enzyme cascade in Leydig and granulosa cells. HCG’s extended half-life compared to LH makes it more practical for receptor stimulation studies requiring sustained agonist presence in biological systems.

Testicular Steroidogenesis and Leydig Cell Biology Research — HCG is the standard gonadotropin stimulus for studying Leydig cell steroidogenesis — with research examining how LH/hCG receptor activation drives testosterone biosynthesis through StAR protein-mediated cholesterol transport into mitochondria, CYP11A1-mediated cholesterol side chain cleavage, and the downstream steroidogenic enzyme cascade converting pregnenolone through progesterone, 17α-hydroxyprogesterone, androstenedione, and ultimately testosterone. Studies have used HCG as a defined gonadotropin stimulus to characterise each step of the Leydig cell steroidogenic pathway and to examine how steroidogenesis is regulated at the molecular level by gonadotropin receptor signalling.

Ovarian Biology and Folliculogenesis Research — HCG’s role in ovarian biology — as a surrogate for the LH surge that triggers ovulation in reproductive research models — has made it a central research tool for studying follicle luteinisation, corpus luteum formation and progesterone production, oocyte maturation, and the molecular events of the ovulatory cascade. Research has used HCG to examine granulosa cell luteinisation biology, cumulus-oocyte complex maturation, and the gene expression changes driving the transition from follicular to luteal phase ovarian biology.

Hypothalamic-Pituitary-Gonadal Axis Research — HCG has been used extensively in HPG axis research — serving as a defined, long-acting LH receptor stimulus for studying feedback regulation in the hypothalamic-pituitary-gonadal axis. Studies have examined how HCG-driven gonadal steroidogenesis influences hypothalamic GnRH secretion, pituitary LH and FSH release, and the negative feedback dynamics that regulate gonadotropin secretion — contributing to fundamental understanding of HPG axis regulatory biology.

Testosterone Biosynthesis Pathway Research — HCG is the standard stimulus for studying testosterone biosynthesis at the cell and tissue level — with research examining each enzymatic step in the Leydig cell steroidogenic pathway, the regulation of steroidogenic enzyme expression by LH/hCG receptor signalling, and how the steroidogenic cascade is modulated by intracellular signalling intermediates, co-factors, and rate-limiting steps. These pathway research studies have provided fundamental mechanistic understanding of androgen biosynthesis biology.

Extragonadal LH/hCG Receptor Biology Research — The discovery of LH/hCG receptor expression in multiple non-gonadal tissues has opened a growing secondary research dimension for HCG — with studies examining LH/hCG receptor biology in thyroid tissue, adrenal cortex, brain, uterus, kidney, and immune cells. Research has characterised how HCG influences thyroid function through shared alpha subunit interactions, examined the role of LH/hCG receptor signalling in uterine biology and implantation, and explored potential roles of HCG in brain function through CNS LH/hCG receptor expression — establishing extragonadal HCG biology as an active and expanding research area.

Male Hypogonadism and Steroidogenesis Deficiency Pre-Clinical Research — HCG has been studied extensively in pre-clinical models of hypogonadism and steroidogenesis deficiency — with research examining how gonadotropin stimulation restores Leydig cell steroidogenic capacity and testosterone production in models of gonadotropin deficiency, gonadal dysfunction, and primary steroidogenesis impairment. These pre-clinical studies have contributed to understanding of the mechanisms of gonadotropin-dependent testosterone restoration and the biology of Leydig cell steroidogenic recovery following gonadotropin stimulation.

Pregnancy Biology and Trophoblast Research — HCG’s physiological origin in placental trophoblast cells has made it a research tool for studying trophoblast biology — with research examining HCG production dynamics during early pregnancy, the role of HCG in maintaining corpus luteum function during the luteal-placental transition, trophoblast invasion and implantation biology, and the angiogenic properties of HCG in the uterine environment. These pregnancy biology studies have contributed to fundamental understanding of early gestation endocrinology.

Receptor Desensitisation and Down-Regulation Research — HCG’s extended half-life and potent LH/hCG receptor activation have made it a useful tool for studying receptor desensitisation and down-regulation in gonadal tissue — with research examining how sustained gonadotropin receptor stimulation influences receptor internalisation, uncoupling from G-proteins, and the homeostatic mechanisms that limit steroidogenic responses to prolonged gonadotropin exposure. These desensitisation studies have contributed to understanding of LH/hCG receptor regulatory biology and have practical implications for the design of gonadotropin stimulation research protocols.

Comparative Gonadotropin Pharmacology Research — HCG is used alongside LH, FSH, and recombinant gonadotropin analogues in comparative gonadotropin pharmacology research — examining how differences in glycosylation, receptor binding affinity, half-life, and signalling bias between gonadotropin family members determine their distinct biological profiles in reproductive endocrinology research models.

What Do Studies Say About HCG?

HCG has one of the most extensive research literatures of any reproductive hormone — spanning gonadal steroidogenesis, reproductive endocrinology, gonadotropin receptor pharmacology, and an expanding body of non-reproductive biology research accumulated across decades of pre-clinical and translational investigation.

LH/hCG Receptor Signalling Comprehensively Characterised — Research has established a detailed molecular picture of LH/hCG receptor activation and downstream signalling — with studies characterising the cAMP/PKA pathway as the primary intracellular cascade driving steroidogenesis, and subsequent research identifying additional signalling pathways including PI3K/Akt and MAPK/ERK activation downstream of LH/hCG receptor engagement. Studies examining receptor activation kinetics, G-protein coupling specificity, receptor internalisation dynamics, and the molecular determinants of receptor activation versus internalisation have provided comprehensive mechanistic understanding of LH/hCG receptor pharmacology that has been foundational for interpreting all downstream gonadotropin biology research.

Leydig Cell Steroidogenesis Pathway Established — Decades of research using HCG as the primary gonadotropin stimulus have established the complete molecular pathway of Leydig cell testosterone biosynthesis — from LH/hCG receptor activation through cAMP elevation and PKA activation, to StAR protein phosphorylation and cholesterol transport into the mitochondrial inner membrane, through CYP11A1-mediated cholesterol cleavage, and along the downstream enzymatic cascade to testosterone. These steroidogenesis pathway studies have provided fundamental insights into androgen biosynthesis regulation that have been central to endocrinology research and have established HCG as the standard stimulus for studying Leydig cell steroidogenic biology.

Corpus Luteum Maintenance and Progesterone Production Characterised — Research has characterised HCG’s role in maintaining corpus luteum function during early pregnancy — documenting how HCG-driven LH/hCG receptor activation in luteal cells sustains progesterone biosynthesis during the critical luteal-placental transition period. Studies have examined the molecular mechanisms of HCG-mediated corpus luteum rescue, the regulation of luteal cell steroidogenesis by HCG signalling, and the temporal dynamics of corpus luteum HCG responsiveness — contributing to fundamental understanding of early pregnancy endocrinology.

Extended Half-Life Basis Established — Research has characterised the structural basis for HCG’s extended half-life compared to LH — establishing the role of the unique C-terminal peptide extension on the HCG beta subunit and its sialic acid-rich O-linked glycans in reducing hepatic clearance and extending circulating half-life from LH’s 20–30 minutes to HCG’s 24–36 hours. Studies examining the glycosylation-dependent pharmacokinetics of HCG have contributed to understanding of how glycosylation profile determines gonadotropin clearance rates and have informed the design of long-acting gonadotropin analogues for research applications.

Extragonadal LH/hCG Receptor Expression Documented — Research has documented LH/hCG receptor expression and functional HCG responses in multiple non-gonadal tissues — including thyroid follicular cells where HCG cross-reacts with TSH receptors due to shared alpha subunit homology, uterine endometrium and myometrium where HCG influences implantation biology, brain tissue where LH/hCG receptor expression has been characterised in hypothalamic and limbic regions, adrenal cortex, and immune cells. These extragonadal expression studies have expanded the research significance of HCG far beyond classical reproductive endocrinology — establishing it as a pleiotropic gonadotropin with biological relevance across multiple organ systems.

HPG Axis Feedback Dynamics Characterised — Research using HCG as a defined LH receptor stimulus has contributed substantially to understanding of HPG axis negative feedback regulation — documenting how HCG-driven testosterone elevation suppresses hypothalamic GnRH pulse frequency, reduces pituitary LH secretion, and modulates FSH secretion through both direct and inhibin-mediated feedback mechanisms. These HPG axis studies have provided fundamental insights into the feedback regulatory biology that governs gonadotropin secretion and reproductive hormone homeostasis.

Angiogenic Properties of HCG Documented — Research has characterised angiogenic properties of HCG — with studies documenting HCG-driven stimulation of endothelial cell proliferation, migration, and tube formation through mechanisms involving VEGF pathway activation. These angiogenic properties have been studied in the context of placental vascular development, uterine angiogenesis during implantation, and potentially in tumour biology contexts where HCG expression by non-trophoblast tumour cells may contribute to tumour vascularisation. These findings have added a vascular biology dimension to HCG research beyond its classical reproductive endocrinology focus.

How Does HCG Compare to Related Gonadotropin and Reproductive Hormone Research Compounds?

Feature	HCG	LH (Luteinising Hormone)	FSH	GnRH	hMG
Type	Placental glycoprotein gonadotropin	Pituitary glycoprotein gonadotropin	Pituitary glycoprotein gonadotropin	Hypothalamic decapeptide	Urinary gonadotropin mixture
Subunit Structure	Alpha + unique beta-CTP	Alpha + LH-beta	Alpha + FSH-beta	Single chain decapeptide	LH + FSH mixture
Primary Receptor	LH/hCG receptor (LHCGR)	LH/hCG receptor (LHCGR)	FSH receptor (FSHR)	GnRH receptor — pituitary	Both LHCGR and FSHR
Half-Life	~24–36 hours	~20–30 minutes	~3–4 hours	~2–4 minutes	Variable
Steroidogenesis Stimulation	Strong — testosterone/progesterone	Strong — testosterone/progesterone	Indirect — via FSH-mediated pathways	Indirect — via LH/FSH release	Both pathways
Primary Research Use	LH receptor agonism, steroidogenesis, Leydig cell biology	Reference endogenous LH biology	Folliculogenesis, spermatogenesis	HPG axis stimulation research	Combined gonadotropin research
Standardisation	IU — biological activity	IU — biological activity	IU — biological activity	Mass-based	IU — biological activity
Research Profile	Extensively studied	Extensively studied	Extensively studied	Extensively studied	Well-documented

Product Specifications

Parameter	Detail
Name	Human Chorionic Gonadotropin (HCG)
Type	Recombinant Human Glycoprotein Gonadotropin
Structure	Heterodimer — shared alpha subunit + unique HCG beta subunit with CTP
Biological Activity	IU-standardised — verified against international reference preparation
Receptor Target	LH/hCG Receptor (LHCGR) — Gs-coupled GPCR
Primary Mechanism	cAMP/PKA-driven steroidogenesis — Leydig and granulosa cell biology
Half-Life	~24–36 hours — extended by CTP O-linked sialylated glycans
Key Advantage	Long-acting LH receptor agonism — 24–36 hour half-life vs LH’s 20–30 minutes
Standardisation	International Units (IU) of biological activity
Verification	Biological activity assay, SDS-PAGE, HPLC
Form	Lyophilised Powder
Solubility	Sterile water for injection or bacteriostatic water
Storage (Powder)	2–8°C refrigerated — protect from light
Storage (Reconstituted)	2–8°C — use within 30 days if bacteriostatic water used
Manufacturing	GMP Manufactured
Intended Use	Research use only

HCG Reconstitution — Important Note

HCG should be reconstituted in sterile water for injection or bacteriostatic water — bacteriostatic water is recommended for research preparations where the reconstituted solution will be used across multiple experimental sessions, as the benzyl alcohol preservative extends the usable life of the reconstituted preparation to approximately 30 days when stored refrigerated at 2–8°C. Sterile water without preservative is appropriate for single-session preparations. Add diluent slowly down the inside wall of the vial and swirl gently — do not inject directly onto the lyophilised powder and do not shake or vortex vigorously, as HCG is sensitive to mechanical agitation that can cause glycoprotein denaturation and loss of biological activity. Prepare at the concentration required for your research protocol. As a glycoprotein, HCG can adsorb to standard plastic surfaces at low concentrations — use low-binding tubes where possible for diluted working solutions. Do not freeze reconstituted HCG preparations — freezing of the reconstituted solution can compromise glycoprotein integrity and biological activity.

Bacteriostatic water for HCG reconstitution is available separately in our Ireland research solvent range.

Buy HCG in Ireland — What’s Included

Every order of HCG in Ireland includes:

✅ Batch-Specific Certificate of Analysis (CoA)

✅ Biological Activity Verification Report

✅ SDS-PAGE and HPLC Data

✅ Sterility & Endotoxin Testing Report

✅ Reconstitution Protocol — including bacteriostatic water guidance

✅ Technical Research Support

Frequently Asked Questions — HCG Ireland

Can I Buy HCG in Ireland?

Yes — we supply research-grade HCG to researchers and institutions across Ireland with fast dispatch and full batch documentation. This compound is supplied strictly for laboratory research purposes only.

What is the Difference Between HCG and LH in Research Terms?

HCG and LH share the same receptor — LHCGR — and produce equivalent biological responses through the same cAMP/PKA downstream signalling cascade in Leydig cells, granulosa cells, and other LH-responsive tissues. The critical difference is pharmacokinetic — LH has a circulating half-life of only 20–30 minutes due to rapid renal clearance and desialylation, while HCG’s unique C-terminal peptide extension carrying sialic acid-rich O-linked glycans extends its half-life to approximately 24–36 hours. In research terms, this half-life difference means that LH requires frequent administration to maintain sustained receptor stimulation — making it impractical for protocols requiring prolonged LH receptor engagement — while HCG provides days-long receptor stimulation from a single administration. For most research applications requiring LH receptor agonism, HCG is the more practical research compound — with LH reserved for research specifically examining the biology of endogenous, short-acting gonadotropin pulse dynamics that HCG’s extended half-life cannot replicate.

What is the LH/hCG Receptor and Why Does its Broad Tissue Distribution Matter for Research?

The LH/hCG receptor is a G-protein coupled receptor of the leucine-rich repeat glycoprotein hormone receptor subfamily — characterised by a large extracellular domain that accommodates the glycoprotein gonadotropin ligand and a seven-transmembrane domain that couples to Gs proteins to activate adenylyl cyclase and elevate intracellular cAMP. Its expression extends well beyond the classical gonadal locations — with documented expression in thyroid follicular cells, adrenal cortex, uterine endometrium and myometrium, placental trophoblasts, brain regions including hypothalamus and limbic system, kidney proximal tubule, liver, and immune cells. This broad tissue distribution means that HCG administration influences biology in multiple organ systems simultaneously — making LH/hCG receptor tissue distribution an important consideration in research design, particularly in pre-clinical in vivo models where systemic HCG administration activates gonadal and extragonadal receptors concurrently. Understanding which biological effects are attributable to gonadal steroidogenesis versus direct extragonadal LH/hCG receptor activation is an important mechanistic question in HCG pre-clinical research.

How Does HCG Standardisation in International Units Work?

HCG is quantified in International Units (IU) of biological activity rather than simple protein mass because its biological potency is significantly influenced by its glycosylation profile — particularly the sialylation of its complex O-linked and N-linked glycans — which affects both receptor binding affinity and circulating half-life independently of the protein backbone. International Units are defined against internationally agreed reference preparations calibrated for biological activity in standardised bioassays — ensuring that an IU of one HCG preparation produces an equivalent biological response to an IU of any other preparation meeting the reference standard, regardless of minor glycosylation variation between production batches. This activity-based standardisation is essential for research reproducibility when comparing experiments across different HCG preparations or replicating research designs from the published literature — making IU the scientifically appropriate unit for HCG research applications.

What is the C-Terminal Peptide of the HCG Beta Subunit and Why is it Significant?

The C-terminal peptide (CTP) is a unique 24 amino acid extension on the HCG beta subunit — absent from the LH beta subunit — that carries four O-linked glycosylation sites heavily decorated with sialic acid residues. These sialic acid groups are the primary structural basis for HCG’s extended circulating half-life — with sialylated glycans dramatically reducing clearance through hepatic asialoglycoprotein receptors and renal filtration, extending half-life from LH’s 20–30 minutes to HCG’s 24–36 hours. The CTP’s significance extends beyond pharmacokinetics — it is also exploited in the design of long-acting gonadotropin analogues and fusion proteins, where the CTP sequence has been used to extend the half-life of other gonadotropins and peptide hormones through recombinant fusion approaches. Understanding the CTP’s structural and pharmacokinetic biology is therefore important for interpreting both HCG research findings and the broader field of gonadotropin analogue pharmacology research.

What is HCG’s Role in Male Reproductive Biology Research?

In male reproductive biology research, HCG serves as the primary pharmacological stimulus for Leydig cell testosterone production — providing a defined, long-acting LH receptor signal for studying testicular steroidogenesis mechanisms, Leydig cell biology, and the HPG axis regulation of testosterone biosynthesis. Research has used HCG to examine each step of the Leydig cell steroidogenic pathway — from StAR-mediated cholesterol transport through the complete enzymatic cascade to testosterone — and to characterise how Leydig cell steroidogenic capacity is regulated by gonadotropin signalling at the molecular level. Beyond steroidogenesis, HCG has been studied in the context of spermatogenesis support — examining how Leydig cell testosterone production driven by HCG maintains intratesticular testosterone concentrations required for normal spermatogenic function in pre-clinical models. These male reproductive biology research applications have made HCG an indispensable research tool in andrology and male endocrinology research.

Has HCG Biology Been Studied Outside of Reproductive Research?

Yes — the discovery of LH/hCG receptor expression in multiple non-reproductive tissues has generated a growing body of extragonadal HCG biology research. Brain LH/hCG receptor research has examined potential roles of gonadotropin signalling in hypothalamic function, cognition, and neuroprotection — with some studies characterising LH/hCG receptor expression in hippocampal and limbic regions and examining potential connections between gonadotropin signalling and neurodegenerative biology. Thyroid biology research has characterised HCG’s cross-reactivity with TSH receptors — relevant to understanding gestational hyperthyroidism during high-HCG first trimester pregnancy. Uterine biology research has examined HCG’s roles in endometrial receptivity, implantation biology, and myometrial function. Angiogenesis research has documented HCG-driven endothelial biology relevant to placental vascular development. Together, these extragonadal research areas have established HCG as a pleiotropic hormone with biological significance extending well beyond its classical reproductive endocrinology context.

What Purity and Activity Standards are Recommended for HCG Research?

Verified biological activity — confirmed against international reference preparations — combined with ≥99% protein purity is strongly recommended for LH/hCG receptor binding studies, Leydig cell steroidogenesis research, ovarian biology experiments, HPG axis research, and pre-clinical in vivo reproductive biology models. As a glycoprotein, HCG’s biological activity is determined by both protein sequence and glycosylation profile — making biological activity verification essential alongside purity assessment for ensuring research reproducibility. All HCG Ireland stock is supplied with biological activity verification documentation alongside standard purity characterisation data.

How Do I Reconstitute HCG for Laboratory Use?

Allow the vial to reach room temperature before opening. Add sterile water for injection or bacteriostatic water slowly down the inside wall of the vial and swirl gently — do not inject directly onto the lyophilised powder and do not shake or vortex. Use bacteriostatic water if the reconstituted preparation will be used across multiple experimental sessions — the benzyl alcohol preservative extends usable life to approximately 30 days at 2–8°C. Prepare at your protocol’s required concentration. Use low-binding tubes for diluted working solutions to minimise glycoprotein surface adsorption losses. Do not freeze reconstituted HCG — store refrigerated at 2–8°C only. Avoid repeated temperature cycling of the reconstituted solution.

Research Disclaimer

HCG is supplied exclusively for legitimate scientific research purposes conducted within licensed laboratory environments. This product is not intended for human consumption, self-administration, or any therapeutic application. It must be handled by qualified researchers in compliance with applicable Irish and EU regulations and institutional ethics guidelines. By purchasing, you confirm that this compound will be used solely for approved in vitro or pre-clinical research purposes.