HCG — identity, handling and published literature

Human chorionic gonadotrophin (hCG) is a heterodimeric glycoprotein hormone, not a simple synthetic peptide, supplied for laboratory use as a lyophilised powder in a sealed vial and labelled by biological potency in international units rather than by mass.

Presentation and physical properties

hCG is supplied as a white to off-white lyophilised solid in a sealed vial, with a nominal content stated in international units (IU). The NovoVita catalogue item is a 10,000 IU vial. Because potency is assigned by bioassay and immunoassay against an international reference preparation, the label carries no mass figure, and none can be inferred from it without the specific activity of that particular preparation.

The molecule is a non-covalently associated heterodimer of two distinct glycosylated polypeptide chains:

• α chain (gene CGA) — 92 amino acid residues in the mature chain, following removal of a 24-residue signal peptide from a 116-residue precursor. This chain is common to hCG, luteinising hormone, follicle-stimulating hormone and thyroid-stimulating hormone; it carries none of the hormone-specific information.
• β chain (gene CGB3, also annotated CGB, CGB5, CGB8) — 145 amino acid residues in the mature chain, following removal of a 20-residue signal peptide from a 165-residue precursor. This chain confers receptor specificity and carries a C-terminal extension not present in luteinising hormone.

Both chains are glycosylated. UniProt annotates the β chain with two N-linked glycosylation sites on asparagine residues and four O-linked sites on serine residues within the C-terminal extension. Carbohydrate accounts for roughly 30 per cent of the mass of the intact hormone, and the apparent molecular weight of the glycosylated heterodimer is customarily quoted at approximately 36–38 kDa. That figure is an approximation by necessity: glycan occupancy and branching vary between source materials and between production lots, so hCG does not possess a single exact mass in the way a synthetic peptide does.

For the same reason, no single molecular formula and no linear sequence string is quoted for this substance. A two-chain glycoprotein with variable carbohydrate is not describable by either. Where a supplier or database publishes a formula for hCG, it refers to the unglycosylated polypeptide backbone only and is not a description of the material in the vial.

The crystal structure reported by Lapthorn and colleagues in Nature in 1994 established the fold [1]. Each subunit adopts a similar topology in which three disulphide bonds form a cystine knot, and the heterodimer is stabilised by a segment of the β subunit that wraps around the α subunit and is covalently fastened, in the authors’ description, “like a seat belt”, by the disulphide Cys 26–Cys 110. That architecture is the reason the dimer is comparatively robust to handling while the isolated subunits are not, and it is why reduction of disulphide bonds destroys identity rather than merely denaturing the protein.

The lyophilised solid is freely soluble in water and in aqueous buffers at physiological pH. It is hygroscopic in the manner typical of freeze-dried protein and should be brought to ambient temperature before a sealed vial is opened.

Reconstitution arithmetic

The arithmetic for hCG differs from that for a peptide vial in one respect that matters, and it should be stated before any table is read.

The vial is labelled in international units, so the working concentration is IU per millilitre, not milligrams per millilitre. The international unit is a unit of biological activity assigned by comparison with a WHO International Standard, not a unit of mass. Published specific activities for purified urinary hCG preparations vary widely with the purification route — figures of the order of several thousand IU/mg for partly purified material and above 10,000 IU/mg for highly purified material have been reported — so an IU figure cannot be converted to a mass figure without the specific activity stated by the manufacturer for that lot. Any mg/mL figure derived by assuming a specific activity is a guess wearing the clothes of a measurement.

The relationship is therefore:

Concentration (IU/mL) = vial content (IU) ÷ volume of diluent added (mL)

and, inverted:

Volume (mL) = amount (IU) ÷ concentration (IU/mL)

Worked for a 10,000 IU vial at three common diluent volumes. A U-100 insulin syringe is graduated so that 100 units correspond to 1 mL, and one graduation therefore corresponds to 0.01 mL.

Two arithmetic caveats. First, the figures are nominal: the final solution volume is the diluent volume plus the small displacement volume of the dissolved solid and of any excipient present, so the true concentration is marginally lower than the table states. For a freeze-dried protein at this scale the difference is small, but it is not zero, and it is a systematic error rather than a random one. Second, the third row does not divide evenly; 10,000 ÷ 3 is 3,333.33 recurring, and rounding it to 3,333 introduces an error of about one part in ten thousand. Where the arithmetic must be exact, choose a diluent volume that divides the vial content evenly.

This section covers the concentration relationship only. It does not state, and must not be read as stating, what quantity should be withdrawn for any purpose.

Storage and stability

Two distinct stability questions apply, and the answers are different.

The sealed lyophilised solid. Freeze-dried glycoprotein is the stable form. Licensed medicinal products give a useful indication of the range: the US prescribing information for a urinary-derived chorionic gonadotropin product specifies storage of the dried powder at controlled room temperature, 15–30 °C, while the UK Summary of Product Characteristics for the recombinant product Ovitrelle — which is supplied as a solution rather than a powder — specifies 2–8 °C with the option of storage at or below 25 °C for up to 30 days within shelf life. Research-grade lyophilised material is conventionally held refrigerated or frozen, protected from light and from moisture ingress, with the stopper left undisturbed until use.

The reconstituted solution. Once in solution, hCG is a dilute protein in an aqueous environment and is subject to the usual failure modes: hydrolysis, aggregation, adsorption to container surfaces and microbial growth. The relevant published figure is instructive but must be read with its condition attached: the US labelling for a multi-dose urinary hCG product states that the reconstituted preparation is stable for 60 days when refrigerated — with the benzyl-alcohol-preserved diluent supplied in that pack. That figure does not transfer to an unpreserved diluent. Bacteriostatic water contains approximately 0.9 per cent benzyl alcohol as a preservative; sterile water contains no preservative at all, and a solution made with it has no antimicrobial protection whatever.

General laboratory practice for a glycoprotein of this class: reconstitute gently down the vial wall rather than directly onto the cake, avoid vortexing and foaming, refrigerate at 2–8 °C for short-term working storage, and aliquot before freezing if longer storage is required so that repeated freeze–thaw cycles are avoided. At low concentrations, adsorptive loss to glass and plastic surfaces is a real and often underestimated effect; carrier protein is used in some analytical workflows for this reason.

Analytical identity

Confirming the identity of hCG is a materially harder problem than confirming the identity of a synthetic peptide, and the reason is glycosylation. A synthetic peptide has one correct mass; hCG has a distribution of masses, and the distribution itself differs between urinary-derived and recombinant material and between production lots.

The review by Stenman and Alfthan [4] sets out the central analytical difficulty directly: hCG circulates and is measured as several different molecular forms — the intact heterodimer, the free β subunit and, in urine, the β-core fragment produced by metabolic breakdown — and different assays detect these forms to different degrees. An assay result for “hCG” is therefore meaningless without knowing which forms the assay recognises. Assays measuring intact hCG and free β together are used for one purpose; assays specific to the intact dimer for another.

Techniques that bear on identity of the substance itself, rather than on quantitation in a biological matrix:

• SDS-PAGE under reducing and non-reducing conditions — separates the two chains under reducing conditions and demonstrates the associated dimer under non-reducing conditions.
• Size-exclusion chromatography — resolves intact dimer from free subunits and from aggregate.
• Immunoassay with defined specificity — distinguishing intact heterodimer from free β subunit, as discussed in [4].
• LC-MS/MS — used in doping-control laboratories; Butch and Woldemariam [18] compared an intact hCG immunoassay against a total hCG assay and against LC-MS/MS in doping control urine samples, reporting that the intact assay discriminated better than the total assay but read slightly high against the mass-spectrometric method.
• Glycan profiling — the only approach that addresses the carbohydrate component, which is where urinary-derived and recombinant material differ most.
• Potency assignment — by bioassay or calibrated immunoassay against a WHO International Standard for chorionic gonadotrophin, maintained by the National Institute for Biological Standards and Control. This is the measurement that produces the IU figure on the label, and it is a measurement of activity, not of identity.

The practical consequence is that no single instrument reading confirms hCG. Mass alone cannot, because there is no single correct mass. Immunoreactivity alone cannot, because free β subunit and fragments cross-react. Identity requires that chain composition, dimer integrity and assigned potency all agree.

What the published literature investigated

hCG has one of the longest and largest published literatures of any substance in this catalogue. It has been in clinical use since the 1930s, is the analyte of the pregnancy test, and is the subject of randomised controlled trials, Cochrane systematic reviews and meta-analyses running to many hundreds of publications. What follows is a structured sample of that record, not a summary of it.

Structural and in vitro work

Lapthorn and colleagues determined the crystal structure of hCG and reported it in Nature in 1994 [1], establishing the cystine-knot fold shared across the glycoprotein hormone family and the “seat belt” disulphide arrangement by which the β subunit is fastened around the α subunit. The authors described this feature as essential both to subunit association and to receptor binding.

Duan and colleagues reported four cryo-electron microscopy structures of the full-length luteinising hormone–choriogonadotropin receptor (LHCGR) in inactive and active states in Nature in 2021 [2]. The study described a “push-and-pull” activation mechanism in which the hormone pushes the extracellular domain while a hinge loop pulls it toward the transmembrane domain, and identified a conserved ten-residue fragment acting as a tethered agonist.

Anderson and Mendelson [5] investigated the regulation of steroidogenesis in primary cultures of rat Leydig cells, examining the effect of hCG and dibutyryl cyclic AMP on synthesis of cholesterol side-chain cleavage cytochrome P-450 and adrenodoxin. Martinelle and colleagues [6] reported that extracellular signal-regulated kinases are involved in the acute activation of steroidogenesis in immature rat Leydig cells by hCG. Both are cell-culture studies of signalling mechanism.

Rodent work

Fukushima and colleagues [7] studied gonadotropin-regulated testicular RNA helicase (GRTH/DDX25) as a negative regulator of luteinising/chorionic gonadotrophin hormone-induced steroidogenesis in Leydig cells, comparing cells from GRTH-null mice with wild-type controls and identifying steroidogenic acute regulatory protein (StAR) as central to the effect.

Yilmaz and colleagues [8] examined the influence of hormonal treatment with β-hCG for cryptorchidism on subsequent fertility in rats, a study addressing a question that the human trial literature had raised but could not readily answer.

Human clinical literature

The human literature is large, long-standing and includes randomised controlled trials and Cochrane-level systematic reviews. That is a fact about the evidence base and worth stating plainly, because it is unusual among the compounds in this library.

In male hypogonadotrophic hypogonadism, Büchter and colleagues [9] reviewed 42 cases treated with pulsatile GnRH or with hCG in combination with human menopausal gonadotrophin. Shankar and colleagues [10] reported a multicentre study of corifollitropin alfa combined with hCG in adolescent boys with hypogonadotropic hypogonadism in the Journal of Clinical Endocrinology and Metabolism in 2022. Liu and colleagues [11] reported on hCG combined with human menopausal gonadotrophin and a GnRH pump in male adolescents with congenital hypogonadotropic hypogonadism. Grob and colleagues [12] followed up fertility outcomes in male adults with congenital hypogonadotropic hypogonadism who had been treated during puberty with hCG and recombinant FSH. Trinh and colleagues [13] reported a prospective study of hCG combined with clomifene citrate in male hypogonadotropic hypogonadism.

In assisted reproduction, the European Recombinant Human Chorionic Gonadotrophin Study Group [14] reported a multicentre randomised controlled trial in Human Reproduction in 2000 comparing recombinant hCG against urinary hCG for induction of final follicular maturation and early luteinisation. Craciunas and colleagues [15] conducted a Cochrane systematic review and meta-analysis of intrauterine administration of hCG in subfertile women undergoing assisted reproduction, updated in 2018; the review reported moderate-quality evidence of improved live birth rates with intrauterine hCG at 500 IU or above at cleavage-stage embryo transfer, insufficient evidence at blastocyst transfer, and no evidence that miscarriage was reduced.

In cryptorchidism, Wei and colleagues [16] conducted a meta-analysis of randomised controlled trials and concluded that hCG treatment was no more effective than placebo, and not superior to GnRH. Oliveira and colleagues [17] reported gonadal response to a single-dose stimulation test with recombinant hCG in patients with isolated prepubertal cryptorchidism — a diagnostic rather than therapeutic application.

Anti-doping and detection literature

Because hCG is prohibited in male athletes, a distinct body of analytical literature exists on its detection. Goodrum and colleagues [3] studied the influence of multiple hCG administrations on serum and urinary steroid Athlete Biological Passport profiles in males, published in Drug Testing and Analysis in 2023. Butch and Woldemariam [18] measured urinary hCG isoform concentrations in doping control samples, comparing intact and total hCG immunoassays against LC-MS/MS.

Weight-loss literature

hCG has been the subject of a persistent commercial weight-loss claim since the 1950s, and the literature on it is unusually clear. Lijesen and colleagues [19] conducted a criteria-based meta-analysis published in the British Journal of Clinical Pharmacology in 1995 and concluded that there is no scientific evidence that hCG is effective in the treatment of obesity. This finding is recorded here because the claim continues to circulate and because it has attracted regulatory enforcement, described below.

Reviews

Cole [20] reviewed the biological functions of hCG and hCG-related molecules in Reproductive Biology and Endocrinology in 2010, making the point that “hCG” is a term covering several distinct molecules produced by different cells with different functions — the villous syncytiotrophoblast hormone, hyperglycosylated hCG, the free β subunit produced by some malignancies, and pituitary hCG. That heterogeneity is a recurring source of confusion in both the analytical and the clinical literature.

Evidence gaps and limitations

State plainly what the record does not contain.

There is no defined chemical identity in the sense that applies to a synthetic peptide. No molecular formula, no exact mass, no sequence string. A batch of hCG is characterised by potency, chain composition and glycan profile, and two batches meeting the same potency specification may differ measurably in glycosylation. Anyone treating hCG as a defined chemical entity is applying the wrong model.

Urinary-derived and recombinant material are not interchangeable at the molecular level, whatever their comparative behaviour in a given assay or trial. Where a published study used one, its findings do not automatically transfer to the other, and studies rarely characterise the glycoform composition of the material actually used.

The weight-loss claim has no supporting evidence. Lijesen and colleagues [19] found none in 1995, and no adequately powered trial has overturned that conclusion since. This is not a case of insufficient evidence; it is a case of evidence of absence from a meta-analysis designed to look.

The cryptorchidism evidence is negative. Wei and colleagues [16] found hCG no more effective than placebo. That is a finding worth recording precisely because hCG was used for this indication for decades.

There is essentially no published characterisation literature for research-grade, non-pharmaceutical hCG. The stability figures, storage conditions and potency assignments that exist in the public record derive from licensed medicinal products manufactured to pharmacopoeial specification. Material supplied for laboratory use is not covered by that literature, and stability data for it under laboratory storage conditions is largely absent.

Non-clinical use is unstudied. The human safety record for hCG derives from supervised clinical use in defined populations under specified monitoring. No published literature addresses the safety of use outside those conditions, and the absence of published harm is not evidence of safety.

Regulatory and standards position

hCG matches the active substance of medicines authorised in the United Kingdom. This is the most consequential fact on this page.

United Kingdom. Chorionic gonadotrophin is the active substance of licensed medicinal products. Ovitrelle (choriogonadotropin alfa, recombinant hCG produced in CHO cells) is authorised in Great Britain under marketing authorisation PLGB 11648/0274, held by Merck Serono Ltd, and is a prescription-only medicine. Urinary-derived chorionic gonadotrophin is licensed under brand names including Pregnyl (N.V. Organon) and Choragon (Ferring Pharmaceuticals Ltd), the latter listed in the NHS Dictionary of Medicines and Devices. All are prescription-only medicines under the Human Medicines Regulations 2012.

hCG is not a controlled drug under the Misuse of Drugs Act 1971 and is not scheduled under the Misuse of Drugs Regulations 2001. Its restriction in the UK is as a prescription-only medicine, not as a controlled substance.

The regulatory significance for a research chemical is that hCG falls squarely within the “medicinal product by presentation” analysis. Under MHRA Guidance Note 8 and the reasoning in Ter Voort (C-219/91), it is the claim made about a substance rather than the substance itself that determines whether it is a medicine in law. Because hCG is the active substance of authorised medicines, any statement associating it with a therapeutic purpose engages that analysis immediately and without ambiguity.

European Union. Ovitrelle holds a centralised EU marketing authorisation. Urinary-derived hCG products are authorised nationally across EU member states.

United States. Chorionic gonadotropin for injection products hold FDA approval for defined indications. There is no FDA-approved hCG product for weight loss. On 6 December 2011 the FDA and the Federal Trade Commission jointly issued seven warning letters to companies marketing over-the-counter hCG products labelled as “homeopathic” for weight loss, on the grounds that they were unapproved drugs making unsupported claims; the letters required a response within 15 days and cited the possibility of seizure, injunction or criminal prosecution. This is documented enforcement history against a specific claim made about this specific substance, and it is directly relevant to how it may be described.

WADA. Chorionic gonadotrophin (CG) is named on the WADA Prohibited List at section S2.2.1, “testosterone-stimulating peptides in males”, alongside luteinising hormone (LH), gonadotrophin-releasing hormone (GnRH, gonadorelin) and its agonist analogues, and kisspeptin and its agonist analogues. Section S2 substances are prohibited at all times — in-competition and out-of-competition.

The prohibition applies to male athletes only. This is a precise and deliberate restriction, not a drafting accident: hCG is produced physiologically in pregnancy, so a prohibition applying to female athletes would be unworkable. The operative wording is that use of human chorionic gonadotrophin, luteinising hormone and their releasing factors is prohibited at all times and only for male athletes. A male athlete subject to anti-doping rules commits an anti-doping rule violation through use of hCG whether in or out of competition; a female athlete does not, on this listing.

Reference standards. Potency is assigned against WHO International Standards for chorionic gonadotrophin maintained by the National Institute for Biological Standards and Control (NIBSC). The 5th International Standard carries NIBSC code 07/364, and a 6th International Standard (18/244) has been established. These standards are what make the international unit meaningful; a potency figure not traceable to them is not comparable with one that is.

Material supplied for research use holds no marketing authorisation, is not manufactured to pharmacopoeial specification, and is not a medicine. It must not be represented as an equivalent of, or a substitute for, any authorised product named above.

Laboratory handling and safety

hCG is a protein of human urinary or recombinant mammalian cell origin. Handle in accordance with the supplier’s safety data sheet and local risk assessment.

• Personal protective equipment. Laboratory coat, nitrile gloves and eye protection as a minimum. Change gloves after contact.
• Biological origin. Urinary-derived hCG is a human-source biological material. Standard precautions for handling material of human origin apply, irrespective of the purification and viral-inactivation steps applied upstream.
• Lyophilised powder. Freeze-dried protein is light and readily disturbed. Open sealed vials carefully and avoid generating airborne particulate; protein aerosols are a recognised sensitisation route.
• Reconstitution. Disinfect the stopper before each entry. Introduce diluent slowly down the vial wall. Do not shake or vortex; foaming denatures protein at the air–liquid interface and is a real loss mechanism, not a cosmetic problem.
• Labelling. Record the lot number, the diluent used, the volume added, the resulting concentration in IU/mL and the date of reconstitution on the vial itself. A partly used vial with no reconstitution date on it is unusable data.
• Sharps and waste. Needles and syringes to a compliant sharps container. Dispose of surplus material and contaminated consumables in accordance with local waste regulations.
• Spillage. Contain, absorb, decontaminate the surface and dispose of absorbent material as contaminated waste.
• Not for human or veterinary administration. This material is not sterile-filled to medicinal standard, holds no marketing authorisation, and is not for use in or on humans or animals.

References

1. Lapthorn AJ, Harris DC, Littlejohn A, Lustbader JW, Canfield RE, Machin KJ, Morgan FJ, Isaacs NW. Crystal structure of human chorionic gonadotropin. Nature. 1994;369(6480):455–61. Model: in vitro, X-ray crystallography. PMID 8202136
2. Duan J, Xu P, Cheng X, Mao C, Croll T, He X, Shi J, Luan X, Yin W, You E, Liu Q, Zhang S, Jiang H, Zhang Y, Jiang Y, Xu HE. Structures of full-length glycoprotein hormone receptor signalling complexes. Nature. 2021;598(7882):688–92. Model: in vitro, cryo-electron microscopy. PMID 34552239
3. Goodrum JM, Moore C, Crouch AK, Eichner D, Miller GD. Influence of multiple human chorionic gonadotropin administrations on serum and urinary steroid Athlete Biological Passport profiles in males. Drug Testing and Analysis. 2023;15(11–12):1371–81. Model: human administration study. PMID 37749856
4. Stenman UH, Alfthan H. Determination of human chorionic gonadotropin. Best Practice & Research Clinical Endocrinology & Metabolism. 2013;27(6):783–93. Model: review. PMID 24275190
5. Anderson CM, Mendelson CR. Regulation of steroidogenesis in rat Leydig cells in culture: effect of human chorionic gonadotropin and dibutyryl cyclic AMP on the synthesis of cholesterol side chain cleavage cytochrome P-450 and adrenodoxin. Archives of Biochemistry and Biophysics. 1985;238(2):378–87. Model: in vitro, rat Leydig cell culture. PMID 2986550
6. Martinelle N, Holst M, Söder O, Svechnikov K. Extracellular signal-regulated kinases are involved in the acute activation of steroidogenesis in immature rat Leydig cells by human chorionic gonadotropin. Endocrinology. 2004;145(10):4629–34. Model: in vitro, immature rat Leydig cells. PMID 15242988
7. Fukushima M, Villar J, Tsai-Morris CH, Dufau ML. Gonadotropin-regulated testicular RNA helicase (GRTH/DDX25), a negative regulator of luteinizing/chorionic gonadotropin hormone-induced steroidogenesis in Leydig cells: central role of steroidogenic acute regulatory protein (StAR). Journal of Biological Chemistry. 2011;286(34):29932–40. Model: rodent, GRTH-null mice. PMID 21719703
8. Yilmaz Ö, Akyol İ, Özyurt M, Ateş F, Soydan H, Malkoç E. The influence of hormonal treatment with beta-human chorionic gonadotropin for cryptorchidism on future fertility in rats. Journal of Pediatric Urology. 2015;11(2):92.e1–4. Model: rodent, rat. PMID 25819376
9. Büchter D, Behre HM, Kliesch S, Nieschlag E. Pulsatile GnRH or human chorionic gonadotropin/human menopausal gonadotropin as effective treatment for men with hypogonadotropic hypogonadism: a review of 42 cases. European Journal of Endocrinology. 1998;139(3):298–303. Model: human, clinical trial. PMID 9758439
10. Shankar RR, Shah S, Joeng HK, Mendizabal G, DiBello JR, Guan Y, Stegmann BJ, Nieschlag E, Behre HM, Swerdloff RS, Fox MC, Kaufman KD. Corifollitropin alfa combined with human chorionic gonadotropin in adolescent boys with hypogonadotropic hypogonadism. Journal of Clinical Endocrinology and Metabolism. 2022;107(7):2036–46. Model: human, multicentre study. PMID 35275602
11. Liu Y, Ren XY, Peng YG, Chen SK, Cheng XR, Qin M, Wang XL, Song YN, Fan LJ, Gong CX. Efficacy and safety of human chorionic gonadotropin combined with human menopausal gonadotropin and a gonadotropin-releasing hormone pump for male adolescents with congenital hypogonadotropic hypogonadism. Chinese Medical Journal. 2021;134(10):1152–9. Model: human. PMID 33813517
12. Grob F, Keshwani R, Angley E, Zacharin M. Fertility outcomes in male adults with congenital hypogonadotropic hypogonadism treated during puberty with human chorionic gonadotropin and recombinant follicle stimulating hormone. Journal of Paediatrics and Child Health. 2024;60(2–3):53–7. Model: human, retrospective follow-up. PMID 38572627
13. Trinh TS, Hung NB, Hien LTT, Tuan NA, Pho DC, Dung QA, Do DA, Quang HD, Ai HV, Hung PN. Evaluating the combination of human chorionic gonadotropin and clomiphene citrate in treatment of male hypogonadotropic hypogonadism: a prospective study. Research and Reports in Urology. 2021;13:357–66. Model: human, prospective study. PMID 34164348
14. The European Recombinant Human Chorionic Gonadotrophin Study Group. Induction of final follicular maturation and early luteinization in women undergoing ovulation induction for assisted reproduction treatment — recombinant HCG versus urinary HCG. Human Reproduction. 2000;15(7):1446–51. Model: human, multicentre randomised controlled trial. PMID 10875887
15. Craciunas L, Tsampras N, Raine-Fenning N, Coomarasamy A. Intrauterine administration of human chorionic gonadotropin (hCG) for subfertile women undergoing assisted reproduction. Cochrane Database of Systematic Reviews. 2018;10(10):CD011537. Model: systematic review and meta-analysis of randomised trials. PMID 30341915
16. Wei Y, Wang Y, Tang X, Liu B, Shen L, Long C, Lin T, He D, Wu S, Wei G. Efficacy and safety of human chorionic gonadotropin for treatment of cryptorchidism: a meta-analysis of randomised controlled trials. Journal of Paediatrics and Child Health. 2018;54(8):900–6. Model: meta-analysis of randomised controlled trials. PMID 29655188
17. Oliveira LR, Homma TK, Woloszynek RR, Brito VN, Longui CA. Gonadal response after a single-dose stimulation test with recombinant human chorionic gonadotropin (rhCG) in patients with isolated prepubertal cryptorchidism. Basic and Clinical Andrology. 2016;26:13. Model: human. PMID 27800162
18. Butch AW, Woldemariam GA. Urinary human chorionic gonadotropin isoform concentrations in doping control samples. Drug Testing and Analysis. 2016;8(11–12):1147–51. Model: human, analytical. PMID 27594536
19. Lijesen GK, Theeuwen I, Assendelft WJ, Van Der Wal G. The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis. British Journal of Clinical Pharmacology. 1995;40(3):237–43. Model: meta-analysis. PMID 8527285
20. Cole LA. Biological functions of hCG and hCG-related molecules. Reproductive Biology and Endocrinology. 2010;8:102. Model: review. PMID 20735820

Research use only

This material is supplied strictly for laboratory research use. It is not a medicinal product, holds no marketing authorisation in the United Kingdom or elsewhere, and has not been assessed by any regulator for safety, quality or efficacy in humans or animals.

It is not for human or veterinary use, not for diagnostic use, and not for use in food. It must not be administered to humans or animals. Nothing in this page is a recommendation, an instruction for use, or a statement that this substance produces any effect in a person.

hCG is the active substance of prescription-only medicines in the United Kingdom. This page reports the published literature and the physical characteristics of a laboratory chemical. It does not describe a treatment and makes no therapeutic claim.

Purchasers are responsible for handling this material in accordance with all applicable legislation and institutional requirements, and for satisfying themselves that their intended use is lawful. Athletes subject to anti-doping rules should note the WADA position set out above.