HCG
Published research and evidence base
Human chorionic gonadotropin is a heterodimeric placental glycoprotein hormone that shares an alpha subunit with LH, FSH and TSH and signals through the luteinizing hormone/chorionic gonadotropin receptor (LHCGR), reproducing LH activity with a substantially longer circulating half-life. Urinary-derived hCG and recombinant choriogonadotropin alfa are approved agents used to trigger final oocyte maturation and ovulation in assisted reproduction, to support Leydig-cell testosterone production and induce or maintain spermatogenesis in male hypogonadotropic hypogonadism, and historically as hormonal therapy for undescended testis. Serum hCG measurement is also a core diagnostic assay in pregnancy monitoring and in gestational trophoblastic disease. The evidence base is large and dominated by randomised trials and their syntheses, so recent systematic reviews, network meta-analyses and Cochrane reviews carry most of the weight; controlled evidence does not support hCG as a weight-loss agent.
- Studies cited
- 15
- Published 2023+
- 12
- Newest paper
- 2026
- Last reviewed
- Aug 2026
Recurring themes in the literature
- LH/CG receptor (LHCGR) agonist
- ovulation and final oocyte maturation trigger
- dual trigger (hCG plus GnRH agonist)
- OHSS risk and trigger selection
- luteal phase support
- male hypogonadotropic hypogonadism
- induction of spermatogenesis and fertility restoration
- pubertal induction in males
- cryptorchidism / undescended testis
- intrauterine insemination timing
- hCG assay in pregnancy and gestational trophoblastic disease
- no established role in weight loss
Compound identifiers
15 published studies.
Ordered by strength of study design, then by recency. Every entry links to its source record so the finding can be checked against the paper rather than taken on our word.
- 01Systematic review2026
Intrauterine human chorionic gonadotropin administration before embryo transfer (IHABT): an individual participant data meta-analysis of randomized controlled trials
Zou H, et al. · Hum Reprod Update · individual participant data meta-analysis of randomised controlled trials in IVF/ICSI patients
Pooled individual participant data from randomised trials were used to re-examine whether intrauterine instillation of hCG before embryo transfer alters live birth and clinical pregnancy outcomes, an intervention for which earlier aggregate-data syntheses had reported inconsistent effects.
- 02Systematic review2026
Oocyte maturation triggering in high responders in IVF treatment: a systematic review and network meta-analysis
Beebeejaun Y, et al. · Front Endocrinol (Lausanne) · network meta-analysis of randomised trials in high ovarian responders undergoing IVF
Trigger strategies were compared in patients at elevated risk of ovarian hyperstimulation syndrome, with attention to how GnRH agonist and dual-trigger regimens perform relative to conventional hCG trigger on live birth and OHSS incidence.
- 03Systematic review2026
Efficacy of dual triggering in poor ovarian responders defined according to Bologna and POSEIDON criteria: a systematic review with meta-analysis
Mercorio A, et al. · J Assist Reprod Genet · meta-analysis of trials in poor ovarian responders (Bologna / POSEIDON criteria)
Dual trigger combining hCG with a GnRH agonist was compared with hCG trigger alone in poor responders, addressing oocyte yield and maturation endpoints in a subgroup where trigger optimisation has been proposed but is not standardised.
- 04Systematic review2026
Boosting Male Fertility: The Impact of Gonadotropin Therapy on Hypogonadotropic Hypogonadism-A Systematic Review and Meta-Analysis
Huijben M, et al. · Andrology · meta-analysis of gonadotropin therapy studies in men with hypogonadotropic hypogonadism
hCG-based gonadotropin regimens, with or without added FSH, were pooled for effects on testicular volume, sperm appearance in the ejaculate and pregnancy outcomes in men with hypogonadotropic hypogonadism.
- 05Systematic review2025
Triggering oocyte maturation in in vitro fertilization treatment in healthy responders: a systematic review and network meta-analysis
Beebeejaun Y, et al. · Fertil Steril · network meta-analysis of randomised trials in normal (healthy) responders undergoing IVF
Available randomised evidence comparing hCG, recombinant hCG, GnRH agonist and combined triggers in normal responders was ranked, with the analysis reporting limited certainty for differences in live birth between trigger agents.
- 06Systematic review2025
Reproductive outcome after frozen embryo transfer with hormone replacement therapy according to luteal-phase support protocol: systematic review and network meta-analysis of randomized controlled trials
Etrusco A, et al. · Ultrasound Obstet Gynecol · network meta-analysis of randomised trials of luteal phase support in hormone replacement frozen embryo transfer
Luteal-phase support protocols, including regimens incorporating hCG alongside progesterone routes, were compared for live birth and clinical pregnancy after hormone-replacement frozen embryo transfer.
- 07Systematic review2025
Synchronised approach for intrauterine insemination in subfertile couples
Adesina M, et al. · Cochrane Database Syst Rev · Cochrane systematic review of randomised trials of insemination timing in subfertile couples
Methods of synchronising intrauterine insemination with ovulation, including hCG-triggered timing versus detection of the endogenous LH surge, were reviewed; the evidence for a clear advantage of any single timing strategy was judged limited.
- 08Systematic review2025
Efficacy of Gonadotropin Treatment for Induction of Spermatogenesis in Men With Pathologic Gonadotropin Deficiency: A Meta-Analysis
Muir CA, et al. · Clin Endocrinol (Oxf) · meta-analysis of gonadotropin (hCG +/- FSH) treatment in men with pathological gonadotropin deficiency
Rates of spermatogenesis induction with hCG-based therapy were quantified, and predictors of response such as prior pubertal development, baseline testicular volume and cryptorchidism history were examined.
- 09Systematic review2025
Use of Human Chorionic Gonadotropin (HCG) or HCG-Combined Treatments in Male Infertility: A Systematic Review
Shoaib H, Duffy J, Ahmed K · Cureus · systematic review of hCG monotherapy and hCG-combination regimens in male infertility
Reported semen-parameter and hormonal outcomes were summarised across hCG monotherapy and hCG combined with FSH, hMG or selective oestrogen receptor modulators, including use in men with prior exogenous androgen exposure; study designs were heterogeneous and largely non-randomised.
- 10Systematic review2024
Gonadotropins for pubertal induction in males with hypogonadotropic hypogonadism: systematic review and meta-analysis
Alexander EC, et al. · Eur J Endocrinol · meta-analysis of gonadotropin regimens for pubertal induction in adolescent and young adult males
Gonadotropin regimens, typically hCG with or without FSH, were assessed against testosterone-only induction for testicular growth and subsequent spermatogenic potential in males with hypogonadotropic hypogonadism.
- 11Systematic review2021
Effect of adjunctive hormonal therapy on testicular descent and spermatogenic function among children with cryptorchidism: a systematic review and meta-analysis
Zhang K, Zhang Y, Chao M · Hormones (Athens) · meta-analysis of hormonal therapy (hCG, GnRH) in children with cryptorchidism
Hormonal therapy produced only modest rates of testicular descent relative to surgery, while its effect on later spermatogenic indices remained uncertain, consistent with guideline positions that discourage routine hormonal treatment of undescended testis.
- 12Systematic review1995
The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis
Lijesen GK, Theeuwen I, Assendelft WJ, Van Der Wal G · Br J Clin Pharmacol · criteria-based meta-analysis of controlled trials of hCG in obesity (Simeons protocol)
Across controlled trials, hCG was not found to be more effective than placebo for weight loss, fat redistribution, hunger or wellbeing when combined with a very-low-calorie diet; the authors concluded there was no scientific evidence supporting hCG in the treatment of obesity.
- 13Human clinical2026
Gonadotropin therapy in idiopathic hypogonadal non-obstructive azoospermia (APHRODITE Groups 3-4): a multicenter randomized controlled trial
Chandra V, Esteves SC, Sanagoudar S · Front Reprod Health · multicentre randomised controlled trial in men with idiopathic hypogonadal non-obstructive azoospermia
Gonadotropin therapy was randomised in hypogonadal men with non-obstructive azoospermia classified under the APHRODITE criteria, testing whether hormonal stimulation alters sperm retrieval and semen outcomes in a population where treatment has been largely empirical.
- 14Animal in vivo2026
Luteinizing hormone receptor knockout mouse: What has it taught us?
Huhtaniemi IT · Andrology · review of LHCGR-null (LuRKO) mouse models
Findings from LH/CG receptor knockout mice were synthesised, indicating that LHCGR signalling is dispensable for fetal sexual differentiation initiation but required for postnatal Leydig cell maturation, androgen production and completion of gametogenesis, delineating the receptor pathway through which hCG acts.
- 15In vitro1994
Crystal structure of human chorionic gonadotropin
Lapthorn AJ, et al. · Nature · X-ray crystallography of deglycosylated human chorionic gonadotropin heterodimer
The alpha and beta subunits were shown to adopt a cystine-knot fold related to that of other growth factors, with the subunits associated in an antiparallel arrangement stabilised by a beta-subunit 'seatbelt' segment, establishing the structural basis for glycoprotein hormone assembly and receptor specificity.
What this evidence does not establish.
Comparative evidence remains inconclusive on whether any single trigger agent (hCG, GnRH agonist or dual trigger) improves live birth rather than intermediate oocyte endpoints, and adjunctive uses such as intrauterine hCG instillation and hCG-containing luteal support are supported mainly by small, heterogeneous trials. In men, most data on hCG for spermatogenesis induction come from uncontrolled cohorts in congenital or acquired gonadotropin deficiency, with little randomised evidence for hCG used to preserve or restore fertility during or after exogenous androgen exposure, and no controlled support for hCG in weight management.
Common questions about the research.
- What is HCG?
Human chorionic gonadotropin is a glycoprotein hormone composed of an alpha subunit shared with LH, FSH and TSH plus a hormone-specific beta subunit. It binds the same receptor as luteinising hormone but persists far longer in circulation, which is why research literature treats it as a long-acting LH surrogate.
- How does it differ from HMG?
HCG supplies LH-like activity only. HMG supplies both FSH and LH activity in roughly equal international units. Published male protocols frequently combine the two precisely because hCG on its own does not provide an FSH signal.
- Is there controlled evidence for hCG in weight loss?
No. A criteria-based meta-analysis of controlled trials of the Simeons protocol, published in 1995, found that hCG was not more effective than placebo for weight loss, fat redistribution, hunger or wellbeing when combined with a very-low-calorie diet. The compound's established evidence base concerns triggering final oocyte maturation and ovulation in assisted reproduction, luteal phase support, and Leydig-cell and spermatogenesis endpoints in male hypogonadotropic hypogonadism.
Available from our catalog
For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition. Nothing on this page is medical advice, and no study summarised here should be read as a recommendation.