HCG (Human Chorionic Gonadotropin)

Human chorionic gonadotropin (hCG) is a glycoprotein hormone made up of two subunits: an alpha subunit of 92 amino acids that is shared with LH, FSH and TSH, and a hormone-specific beta subunit of 145 amino acids that gives hCG its receptor selectivity and long circulating half-life. Both subunits carry extensive N- and O-linked glycosylation, giving a molecular weight of roughly 36–37 kDa.

Because it is a large glycoprotein rather than a short synthetic peptide, its potency is expressed in International Units (IU) of biological activity rather than milligrams. In research it serves as a tool compound for probing the luteinizing hormone/choriogonadotropin receptor (LHCGR). This page describes receptor-pathway research only.

It is widely discussed in men's-health, TRT and bodybuilding circles, where it is popularly associated with supporting the body's own testosterone production and fertility signaling.

HCG is anecdotally discussed in fitness and men's-health communities for its purported ability to mimic luteinizing hormone (LH), and it is reputed to help maintain natural testosterone output and testicular function — a frequent topic in conversations about TRT and post-cycle protocols.

Researchers have long studied hCG in reproductive endocrinology for its role in steroidogenesis, ovulation-induction models and fertility research, and it is popularly associated with fertility and hormone-axis support. Related keywords include LH, testosterone, and the HPG axis.

These are areas of active or preclinical investigation and community interest, not outcomes established through this product.

hCG binds the same receptor as luteinizing hormone (LHCGR), a G-protein-coupled receptor expressed in gonadal tissue. Preclinical studies use it to examine receptor activation, cAMP signaling, steroidogenesis in Leydig and granulosa/luteal cell models, and gonadal-axis regulation in animal models. It is also a long-standing reference ligand in reproductive endocrinology and assay development.

These experiments describe mechanisms measured in animal and cell-based research. Laboratory observations do not predict human outcomes.

Supplied as a lyophilized powder and stored sealed in the refrigerator or freezer, protected from light. For research use it is reconstituted with bacteriostatic water, added slowly down the side of the vial and swirled gently rather than shaken — as a large glycoprotein it is more prone than small peptides to foaming and denaturation.

Once reconstituted it is held at 2–8°C for near-term work and should not be frozen and thawed repeatedly; for longer storage it is divided into single-use aliquots.