HCG 5000IU

HCG is the only item in this catalogue measured in international units rather than milligrams, and the reason is structural. Human chorionic gonadotropin is not a synthetic peptide but a heterodimeric glycoprotein: an alpha subunit of 92 residues paired non-covalently with a beta subunit of 145, with carbohydrate accounting for roughly a third of the molecule’s mass of about 37 kDa.

Glycosylation is heterogeneous, and different glycoforms carry different biological activity. Mass therefore does not predict potency, so the material is standardised against an international biological reference preparation and labelled in IU. A milligram figure would tell you less, not more.

The beta subunit is closely homologous to that of luteinising hormone, with an additional C-terminal extension carrying O-linked glycans. Both hormones act at the same receptor, LHCGR, but the extension slows clearance, which is why HCG persists far longer in circulation than LH. Researchers use it as a long-acting LHCGR agonist for that reason.

Published work covers gonadal steroidogenesis, Leydig and granulosa cell response, and receptor desensitisation under sustained stimulation.

Kisspeptin-10 acts at the top of the same reproductive axis, at the hypothalamus. HCG acts at the bottom, on the gonad directly. Studies that need to locate a defect along the axis often use both.

Supplied as a lyophilised powder with a certificate of analysis. Reconstitute with bacteriostatic water, store the sealed vial at -20°C, and keep reconstituted solution at 2-8°C. Glycoprotein hormones tolerate freeze-thaw cycling poorly, so aliquot rather than refreeze.

For in-vitro laboratory research only. Not for human or veterinary use.