RESEARCH MONOGRAPH · KDC-MN-287

Human Chorionic Gonadotropin (HCG)

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 3 min read

Our opinion on this compound

76/100

Decades-old workhorse hormone that quietly does a lot of useful research work, with significant sourcing complexity

HCG is one of those compounds that pre-dates most of the receptor pharmacology people now associate it with. It's a heterodimeric glycoprotein, alpha and beta subunits, where the alpha is shared with LH, FSH, and TSH and the beta is the specificity-defining piece. The result is a molecule that binds and activates the LH/CG receptor with high affinity and a substantially longer half-life than endogenous LH itself. That's the entire mechanistic story and it's why HCG has been a research staple in reproductive endocrinology for 80-plus years.

The clinical evidence base is huge but unevenly distributed. The strong areas are ovulation triggering in IVF (the LH-surge mimicking effect is what drives the final follicle maturation), induced testicular descent in pediatric cryptorchidism, and stimulation of Leydig cell testosterone production in hypogonadotropic males. The literature there is genuinely deep.

What we like: the Leydig cell pharmacology is well-mapped, the dose-response on testicular steroidogenesis is reproducible, and HCG is one of the few molecules that lets you preserve endogenous testicular function during exogenous androgen administration. That last application has been studied to death in fertility preservation research and the mechanism is solid.

What we dont love: the source complexity is real. HCG has historically been purified from pregnant urine (the original product), then more recently produced recombinantly (Ovidrel/Ovitrelle is recombinant alpha-hCG). The two forms are not identical at the glycosylation level, and glycosylation affects half-life and receptor signaling more than people assume. Research-grade urinary HCG has variable bioactivity per IU, and the IU itself is a bioassay-defined unit which is its own can of worms.

Sourcing is the single biggest issue. The urinary product is still made (Pregnyl, Novarel) but supply is geographically variable. Recombinant is cleaner but more expensive and not always available outside pharma-channel. Research-grade HCG from non-pharma suppliers is one of the categories where we see the most QC variance because the bioactivity assays are genuinely hard to run consistently.

For HPG-axis research, HCG is a reference tool. The mechanism is textbook, the literature is deep, and the dose-response on Leydig cells is well-mapped. Just take the sourcing seriously and ask for bioassay confirmation, not just protein quantification.

Evidence: 92
Mechanism: 90
Reliability: 75
Safety: 78
Sourcing: 55
Value: 60
Signal: 75
Staying power: 80

Plain-language summary Intrigue 60 / 100

Human chorionic gonadotropin (hCG) is the placental hormone that pregnancy tests detect. Pharmacologically it is a long-acting mimic of luteinizing hormone (LH): the half-life is about 36 hours versus 30 minutes for natural LH, so it can sustain LH-receptor stimulation for days from a single injection. Clinically it triggers ovulation in IVF and stimulates Leydig cell testosterone production in men. In testosterone replacement therapy, low-dose hCG is added to maintain testicular size and fertility while exogenous testosterone is suppressing the natural pituitary signal. It is also notorious as the centerpiece of the (debunked) hCG diet. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Glycoprotein hormone (LH analog; placental origin)

Human chorionic gonadotropin; a placental glycoprotein hormone that activates the LH receptor; used in IVF, hypogonadism, and HPG axis recovery.

Abstract

Human chorionic gonadotropin (hCG; CAS 9002-61-3; alpha subunit and unique beta subunit; total molecular weight approximately 36800 Da) is a placental glycoprotein hormone composed of an alpha subunit (shared with LH, FSH, and TSH) and a unique beta subunit. The compound is the principal hormone of pregnancy, produced by syncytiotrophoblasts of the implanting embryo and detected as the basis for pregnancy tests. Pharmacologically, hCG acts as an LH receptor agonist with a substantially longer half-life than endogenous LH (approximately 36 hours versus 30 minutes), making it useful as a pharmacological tool to stimulate Leydig cell testosterone production in males or to trigger ovulation in IVF protocols. Approved indications: male hypogonadotropic hypogonadism (testosterone restoration with preservation of fertility), cryptorchidism, and as ovulation trigger in IVF (single 5000 to 10000 IU injection). Off-label use in TRT users to restore testicular function or as part of post-cycle therapy after AAS or SARM use. Plasma half-life of urinary-derived (Pregnyl, Novarel) versus recombinant (Ovidrel) forms are similar; both work clinically. Used as the canonical LH receptor agonist in HPG axis research.

Mechanism of action

Glycoprotein LH receptor agonist with substantially longer half-life than endogenous LH; stimulates Leydig cell testosterone production and triggers ovulation.

Reported research dose ranges

Clinical 500 to 4000 IU subcutaneous or intramuscular every 1 to 3 days for hypogonadism; 5000 to 10000 IU single dose for ovulation trigger; 250 to 500 IU for fertility preservation during TRT.

References

Cole LA. Biological functions of hCG and hCG-related molecules. Reprod Biol Endocrinol 2010.
Hsieh TC, et al. Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. J Urol 2013.
Ramasamy R, et al. Testosterone supplementation versus clomiphene citrate for hypogonadism. J Urol 2014.

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KDC-MN-287

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Human Chorionic Gonadotropin (HCG)

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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