# HCG > A heterodimeric glycoprotein hormone — two different glycosylated subunits — that mimics the LH surge; the pregnancy hormone, also the subject of a debunked diet. - Also known as: Human chorionic gonadotropin, Choriogonadotropin alfa, Ovidrel, Pregnyl, Novarel - Class: Reproductive - FDA approved: Yes - Canonical page: https://www.americanpeptide.com/catalog/hcg ## Overview Human chorionic gonadotropin is the most structurally complex hormone in this catalog. It is not a single chain but a non-covalent heterodimer of two different subunits — a 92-amino-acid alpha subunit (shared with LH, FSH, and TSH) and a 145-amino-acid beta subunit that is specific to hCG — each heavily decorated with sugar chains. That glycosylation is not decoration: it is essential to the hormone’s long circulating half-life and biological activity, and it makes hCG a true glycoprotein biologic, roughly 36–40 kDa, that cannot be captured as a simple amino-acid formula. hCG’s biology is defined by its architecture. The alpha subunit is common to the whole glycoprotein-hormone family (LH, FSH, TSH); specificity comes entirely from the beta subunit and the way the two fold together. Because the subunits are made and then assembled — and because the sugar chains are added by the producing cell — hCG is a genuine glycoprotein: recombinant versions (choriogonadotropin alfa) are made in mammalian (CHO) cells precisely so that human-like glycosylation can occur, while older products are purified from the urine of pregnant women. This is biology that bacterial synthesis cannot reproduce. In medicine it is well established: it triggers ovulation in assisted reproduction, supports early-pregnancy progesterone, and is used in male hypogonadism and to preserve testicular function and fertility — including alongside testosterone therapy, where it keeps the testes signaled. It is also, famously, the hormone that pregnancy tests detect. The drama is the HCG diet. In the 1950s a British physician, Albert Simeons, claimed hCG injections plus a 500-calorie diet caused targeted fat loss. The diet was repeatedly debunked — the weight loss comes from near-starvation, not the hormone — yet it resurfaces continually, and the FDA has explicitly warned that over-the-counter "homeopathic" hCG weight-loss products are illegal and ineffective. A second, quieter misunderstanding surrounds its use in performance and TRT communities. Both make hCG a clean example of a legitimate, well-characterized hormone whose public reputation is dominated by uses it was never validated for. ## Mechanism Acts as an agonist at the LH/CG receptor, reproducing the luteinizing-hormone signal: in women it triggers ovulation and sustains the corpus luteum’s progesterone; in men it stimulates Leydig-cell testosterone production. Its long half-life, conferred by glycosylation, lets a single dose mimic the natural LH surge. ## Chemistry | Property | Value | | --- | --- | | Molecular weight | 36700 Da | | CAS number | 9002-61-3 | ## Research areas Studied in: Ovulation induction, Assisted reproduction, Male hypogonadism, Fertility preservation. ## Key research - Ovulation induction & ART — the approved use, supplying the LH-like trigger for egg release and luteal support. - Male hypogonadism — stimulates endogenous testosterone via the LH/CG receptor; used to maintain testicular function. - Glycoprotein structure — a heterodimer whose shared alpha + specific beta subunits and glycosylation define its activity and half-life. - The HCG diet — repeatedly debunked; the FDA warns OTC homeopathic hCG weight-loss products are illegal and ineffective. - Pregnancy detection — the hormone measured by home and clinical pregnancy tests. ## Storage, handling & synthesis **Storage.** Depending on the product, hCG is stored refrigerated (2–8 °C) and, once reconstituted, used within the label’s window; it must not be frozen. Glycoprotein integrity is sensitive to heat and freeze–thaw. **Handling.** A glycosylated heterodimer sensitive to heat, freezing, and agitation, any of which can dissociate the subunits or aggregate the protein and reduce potency. **Synthesis.** hCG is either purified from the urine of pregnant women or, as choriogonadotropin alfa, produced recombinantly in mammalian (CHO) cells so that the essential glycosylation is human-like. Its molecular weight (~36–40 kDa) is approximate and varies with glycosylation, so it is not represented by a single molecular formula. Characterization includes subunit identity, glycan profiling, and bioassay potency — glycoprotein-grade analytics well beyond an HPLC purity number. ## FAQs ### What is HCG? Human chorionic gonadotropin — a glycoprotein hormone made of two different glycosylated subunits that mimics luteinizing hormone. It triggers ovulation, supports early pregnancy, and stimulates testosterone in men. It is also the hormone pregnancy tests detect. ### Why is HCG a glycoprotein rather than a simple peptide? It is a two-subunit protein heavily modified with sugar chains that are essential to its half-life and activity. Recombinant hCG is made in mammalian cells so that human-like glycosylation can occur — something bacterial peptide synthesis cannot do. ### Does the HCG diet work? No. The HCG diet has been repeatedly debunked — any weight loss comes from the extreme calorie restriction, not the hormone — and the FDA has warned that OTC homeopathic hCG weight-loss products are illegal and ineffective. ### Is this medical advice? No — this is a research and educational reference. hCG is a prescription hormone with specific approved indications. ## Latest research Recent trials and publications mentioning Human chorionic gonadotropin, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [Extended Letrozole Protocol Versus Letrozole Plus Inositol for Induction of Ovulation in Letrozole Resistant PCOS Women](https://clinicaltrials.gov/study/NCT07635082) — COMPLETED · PHASE2 · NCT07635082 - [The Application of HCG in Luteal Support for Frozen Embryo Transfer in Ovulation Cycle of Obese Women](https://clinicaltrials.gov/study/NCT07633002) — NOT_YET_RECRUITING · NA · NCT07633002 - [Pharmacokinetics of FSH and hCG Following Multiple Dose of Gonadotropins-IBSA.](https://clinicaltrials.gov/study/NCT06659692) — COMPLETED · PHASE1 · NCT06659692 - [Study of Elranatamab for Relapsed or Refractory Myeloma in Patients Previously Exposed to Three-drug Classes](https://clinicaltrials.gov/study/NCT06282978) — ACTIVE_NOT_RECRUITING · PHASE2 · NCT06282978 - [A Pharmacokinetic and Safety Study of MY008211A Tablets in Subjects With Impaired or Normal Hepatic Function](https://clinicaltrials.gov/study/NCT07625618) — COMPLETED · PHASE1 · NCT07625618 - [Subcutaneous Progesterone in Frozen- Thawed Single Euploid Blastocyst Transfer.](https://clinicaltrials.gov/study/NCT04549116) — ACTIVE_NOT_RECRUITING · PHASE3 · NCT04549116 --- Source: AmericanPeptide.com — https://www.americanpeptide.com/catalog/hcg Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.