HCG is a two-chain glycoprotein, not a short peptide: an alpha subunit of 92 amino acids pairs with a beta subunit of 145, and sugar chains make up about 30% of its roughly 37 kDa mass. Because glycosylation varies, its amount is stated in international units, a bioassay measure, rather than in milligrams. It is often confused with LH, which shares the alpha chain and the same receptor. Vials come in 5000 IU and 10000 IU for laboratory research use only.
Ask for the analytical documentation of any lot.
HPLC is the method used to measure purity
Ask for the report for a specific lot through the contact page
Supplied for laboratory research use only
Mass spectrometry is the method used to confirm identity
HCG (human chorionic gonadotropin, written hCG in papers) is a heterodimeric glycoprotein hormone. It has a 92-amino-acid alpha subunit and a 145-amino-acid beta subunit, and it activates the luteinizing hormone/choriogonadotropin receptor (LHCGR). Veracue supplies it as a research material for laboratory work.
The beta subunit gives HCG its specificity, while the alpha chain is shared with LH, FSH and TSH. Sugar chains make up roughly 30% of the mass, so HCG behaves differently from a short synthetic peptide in the lab.
| Product name | HCG (also written hCG) |
| Molecular class | Heterodimeric glycoprotein |
| Alpha subunit | 92 amino acids; shared with LH, FSH and TSH |
| Beta subunit | 145 amino acids; specific to HCG |
| Amino acids, both subunits | 237 (polypeptide backbone only) |
| Carbohydrate share | About 30% of mass (reported range 25 to 40%) |
| Approximate molecular mass | About 37 kDa; published values run from roughly 36 to 39 kDa |
| Receptor | LHCGR |
| Potency unit | International Unit (IU) |
| Research designation | Research Use Only |
These values describe HCG as a molecule in general and do not describe any specific Veracue lot. Source, formulation, purity, potency method and lot results are reported on each lot’s documentation and can be requested through the contact page.
Not in the conventional sense. Across its two subunits HCG has 237 amino acids, its mass is near 37 kDa, and about 30% of that mass is carbohydrate. Short synthetic peptides are much smaller and typically carry no sugar chains.
As a result, several peptide conventions do not carry over. Molecular weight is a range rather than one value, potency is usually expressed in international units, and a mass-spectrometry identity reflects a distribution of glycoforms instead of one exact mass.
The two chains associate without covalent bonds. Isolated subunits do not act on the receptor, and recombining them restores nearly full activity in dissociation and reassociation experiments. A free beta subunit also occurs as a variant, and it behaves differently from the intact dimer in assays and cell models.
| Property | General scientific value |
|---|---|
| Alpha subunit glycosylation | 2 N-linked chains (Asn52, Asn78) |
| Beta subunit glycosylation | 2 N-linked chains (Asn13, Asn30) and 4 O-linked chains (Ser121, Ser127, Ser132, Ser138) |
| Numbering | Mature-subunit numbering |
| Receptor | LHCGR, a 675-amino-acid class A G protein-coupled receptor |
| Genes | CGA for the alpha subunit (chromosome 6); a CGB gene cluster for the beta subunit (chromosome 19) |
The beta chain is about 80% homologous to LH-beta. It also carries a C-terminal extension that LH-beta lacks, and that extension holds the O-linked glycans. Sources give the extension as roughly 24 to 34 residues, depending on where they draw its boundary.
Sugar chains vary from molecule to molecule, so no single molecular weight fits every preparation. Reviews describe several forms with the same amino acid sequence: regular, hyperglycosylated and sulfated HCG, the free beta subunit and a hyperglycosylated free beta subunit. Nicked forms and the beta-core fragment are described as well. Sialic acid and other glycan features change receptor binding, activity and clearance, so glycoform analysis is a research field of its own.
| Feature | HCG | LH |
|---|---|---|
| Structure | Alpha/beta glycoprotein heterodimer | Alpha/beta glycoprotein heterodimer |
| Subunits | Shared alpha (92 amino acids); beta of 145 amino acids | Shared alpha (92 amino acids); a different beta chain |
| Beta chain | Carries a C-terminal extension with O-linked glycans | About 80% homologous to HCG-beta, without that extension |
| Receptor | LHCGR | LHCGR |
| Cell-assay signaling | Different cAMP and beta-arrestin 2 responses from LH | Different responses from HCG in the same readouts |
| Glycosylation | 4 N-linked and 4 O-linked chains; about 30% carbohydrate | Sugar composition differs from HCG, which affects bioactivity and degradation rate |
| Key difference | The beta extension and its glycans | A different beta chain and sugar structure |
The comparison is descriptive and does not rank either molecule.
HCG binds LHCGR, a class A G protein-coupled receptor with a large extracellular domain that also binds LH. The receptor couples mainly to Gαs, which drives adenylyl cyclase, cAMP and protein kinase A signaling. It can also activate ERK and AKT pathways, and at high hormone and receptor levels it couples to Gαq, which raises intracellular calcium.
In one HEK293 model expressing human LHCGR, either HCG or LH raised cAMP within five minutes. Separate work compared recombinant HCG and LH in HEK293 cells and in mouse Leydig tumor cells and reported differences in cAMP and beta-arrestin 2 responses. These are cell-line findings, and which pathway dominates depends on receptor level, cell type and the hormone used.
A receptor-level result describes a measured difference in a defined cell system. Cell-line responses depend on receptor level, cell type and species, and rodent and human cells already behave differently. Findings for one preparation may not apply to another, because recombinant and urine-derived material differ in glycosylation. This page gives no dosing, administration or usage guidance of any kind.
Because the beta chain differs from LH-beta, antibodies aimed at it can separate HCG from LH. The two beta chains are about 80% homologous, and early polyclonal assays suffered LH interference for that reason.
In testing, “beta-hCG” usually refers to assays directed at the beta chain. Some assays detect intact HCG only, and others detect intact HCG plus the free beta subunit, which laboratories call total beta-hCG. Method labels therefore matter. In one split-sample study, 9.3% of participating laboratories (22 of 235) reported intact HCG results as total beta-hCG, and 13.1% (8 of 61) reported total beta-hCG as intact HCG. That finding concerns reporting practice and does not rank assays by accuracy.
Research material sold under Research Use Only terms is a laboratory reagent, not a diagnostic test.
An international unit measures biological activity, not mass. WHO International Standards define it, and the value depends on the assay method. The 5th WHO International Standard for HCG carries 162 IU per ampoule by bioassay and 179 IU per ampoule by immunoassay, so the method belongs next to the number.
IU and mass are not interchangeable without the preparation’s specific activity. Some reference preparations also contain albumin and buffer salts, so vial mass differs from hormone mass. Veracue lists these vials as 5000 IU and 10000 IU.
A certificate of analysis reports the tests a laboratory ran on one lot, with the methods and results it chooses to show. It ties a report to a lot number. It does not show that the lot performs in your assay, that another lot matches it, or that the material suits your model.
| COA item | What to check | Why it matters for HCG |
|---|---|---|
| Identity | Method and result that match HCG | Intact mass is a glycoform distribution, so one exact mass is not expected |
| Source | Urine-derived, recombinant or other | Glycosylation follows the source and affects activity and clearance |
| Purity | The named method behind the figure | A single percentage does not describe glycoform pattern or biological activity |
| Potency | The unit and the assay type | IU values differ between bioassay and immunoassay |
| Protein content | Amount in the stated unit | IU and mass are not interchangeable |
| Formulation | Excipients and carrier | Vial mass can differ from hormone mass |
| Variant information | Intact dimer versus free subunits or fragments | Assays and cell responses treat variants differently |
| Endotoxin and sterility | Reported results, if relevant | Matters for cell-based work |
| Lot traceability | A lot number that matches the label | Ties the data to the material in hand |
| Analytical method | Named method, laboratory and date | Lets you judge whether the result fits your use |
Where documentation is missing for an attribute, treat that attribute as unverified. Source, formulation, purity, potency method and lot results are reported on each lot’s documentation, and the certificate page explains how to request it.
A purity percentage alone cannot describe glycoform distribution or potency. Mass-spectrometry identity for a glycoprotein reflects a distribution of glycoforms rather than one exact mass, and a potency figure is only meaningful with the assay that produced it. General research does not establish the quality of a specific lot, and only lot-specific analytical documentation can describe a particular material.
Ask the Veracue team about documentation for a specific lot, or review the certificate library.
HCG is supplied for laboratory and scientific research only. Veracue’s site policy states that its products are not intended for human or veterinary use, ingestion, injection or any form of administration. HCG research material is not a diagnostic test, and nothing on this page is medical advice. This page provides no dosing, administration or usage guidance of any kind. See the Medical Disclaimer and the Terms and Conditions for sitewide policies.
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