HCG

Classification

Endogenous glycoprotein hormone; an FDA-approved medicine since 1974

Structure and chemistry

Human chorionic gonadotropin is a glycoprotein hormone made of two different subunits, alpha and beta, joined non-covalently. The alpha subunit is identical to that of luteinizing hormone, follicle-stimulating hormone and thyroid-stimulating hormone; the beta subunit is what makes it hCG. It is heavily glycosylated, and that carbohydrate content is functionally important, not decorative. Pharmaceutical hCG is generally purified from the urine of pregnant women; a recombinant version, choriogonadotropin alfa, is a separate product.

What the published research shows

hCG has close to a century of research behind it and a substantial clinical evidence base supporting its approved uses in reproductive medicine. It also has a large body of evidence addressing a non-approved use — weight loss — and that evidence is negative, to the point that FDA requires the negative finding to appear in the product labeling.

Mechanism of action

Its action is virtually identical to pituitary luteinizing hormone, with a small degree of FSH activity as well. It stimulates the Leydig cells of the testis to produce androgens, and the corpus luteum of the ovary to produce progesterone. This LH-mimicking action is why it is used to trigger ovulation and to stimulate endogenous testosterone production.

Development history

hCG was not designed. In 1927 Selmar Aschheim and Bernhard Zondek observed that the blood and urine of pregnant women contained a substance that stimulated the gonads of test animals — a finding that produced both the first pregnancy test and the first commercially available gonadotropin product. Seegar-Jones and colleagues established in the 1940s that the placenta produces it.

Current regulatory status

hCG is an FDA-approved prescription medicine (Novarel, Pregnyl and others; initial US approval 1974) for three specific indications: prepubertal cryptorchidism not due to anatomic obstruction; selected cases of hypogonadotropic hypogonadism in males; and induction of ovulation and pregnancy in anovulatory infertile women appropriately pretreated with menotropins. Its FDA labeling carries an unusually blunt statement about weight loss, reproduced in the key points below. Catalog material sold as HCG is a research-grade item and is not the approved drug product.

Analytical testing

This is a heavily glycosylated two-subunit glycoprotein, not a synthetic peptide, and it is measured in international units of biological activity rather than by mass alone. A meaningful COA should report bioactivity in IU by an appropriate method; a bare HPLC purity percentage does not establish that the alpha and beta subunits are correctly assembled or that glycosylation is intact, and both determine whether the material is active.

Ordering from Great Falls

MontanaPep, also known as Montana Peptides, is an independently owned supplier based at 715 13th Ave S, Great Falls, Montana. Local pickup is available by arrangement, and we ship to research addresses across Montana including Billings, Missoula, Bozeman, Helena, Butte, Kalispell and Havre. Call (406) 799-0812 or email customerservice@montanapep.com.

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