Reproductive & Endocrine

HCG

Human Chorionic Gonadotropin — 237-amino-acid α/β heterodimeric glycoprotein hormone (~36.7 kDa)·Also known as: hCG, Pregnyl, Novarel, Ovidrel (choriogonadotropin alfa, recombinant), Choragon, Chorionic Gonadotropin, CAS 9002-61-3

FDARegulatory status

FDA-approved prescription drug (Rx-only). Urinary-derived hCG (Pregnyl, Novarel) is approved for ovulation induction as part of ART, for treatment of male hypogonadotropic hypogonadism, and for prepubertal cryptorchidism not due to anatomic obstruction. Recombinant choriogonadotropin alfa (Ovidrel) is approved for final follicular maturation / ovulation trigger in ART. OTC homeopathic and non-prescription 'HCG for weight loss' products remain prohibited under the FDA / FTC joint actions originally taken December 6, 2011; that prohibition is still in force as of April 2026.

WADARegulatory status

Prohibited in males at all times (class S2 — Peptide Hormones, Growth Factors, Related Substances and Mimetics) on the 2026 WADA Prohibited List in force January 1, 2026. Not prohibited in females. The 2026 Technical Document on LH/hCG urinary thresholds (TD2026CG) applies; the confirmatory threshold for male athletes remains an intact-hCG concentration consistent with prior years.

Regulatory note ·HCG occupies an unusual position on the regulatory map: it is one of the oldest FDA-approved peptide hormones (Pregnyl approved 1973), it is Rx-only for three narrow indications, it is a controlled-substance-adjacent compound for male athletes under WADA, and it has been the subject of the FDA's most prominent peptide-related consumer enforcement action — the 2011 warning and ensuing product seizures targeting the 'HCG diet' that swept compounding and OTC homeopathic channels. The compound itself is well-characterized. Almost all of the controversy concerns off-label use (weight loss, post-cycle therapy for anabolic steroid users) rather than the approved indications.

§ The quick take

TL;DR · Editor’s summary

HCG is one of the oldest FDA-approved peptide hormones on this site (Pregnyl approved 1973; recombinant Ovidrel approved 2000) and its evidence base for its three approved indications — ovulation trigger in ART, male hypogonadotropic hypogonadism, and prepubertal cryptorchidism — is at or near the ceiling of our rubric. Half a century of clinical use, multiple Phase 3 head-to-head trials of urinary vs recombinant formulations, and clean pharmacokinetic characterization (~40% subcutaneous bioavailability, 24–36 h half-life from the CTP-mediated glycosylation) put the ART and HH grades at A. The reason hCG sits awkwardly on Peptigrade at all is the off-label use.

The 'HCG diet' — hCG injections or homeopathic drops paired with a 500-calorie/day very-low-calorie diet — was studied extensively in the 1970s through the 1990s and found ineffective. Lijesen's 1995 meta-analysis in Br J Clin Pharmacol pooled 14 controlled trials and found no hCG-attributable weight loss, fat redistribution, or appetite suppression beyond what the starvation diet alone produced. On December 6, 2011 the FDA and FTC issued a coordinated enforcement action: seven distributors of OTC homeopathic 'HCG for weight loss' received warning letters, the products were declared unapproved and mislabeled, and they remain illegal to sell in the United States.

That position is unchanged as of April 2026. Post-cycle therapy for anabolic-steroid-induced hypogonadism is the other large off-label population; it is pharmacologically reasonable (hCG directly stimulates the suppressed LH/CG receptor on Leydig cells) but has no RCT, and it is prohibited at all times for male athletes under the 2026 WADA Prohibited List (class S2). If you are reading this as a physician: the approved-indication data is overwhelming and the off-label weight-loss data is a textbook example of a disproven claim that reconstitutes itself under a new packaging every few years.

§ Grade matrix

The grade
per outcome.

One peptide can earn very different grades for different uses. Here is every outcome we’ve graded for HCG, sorted by strength of evidence.

A

Ovulation induction / final oocyte maturation in ART

Strong

FDA-approved since 1973 (Pregnyl) and 2000 (recombinant Ovidrel). Standard of care across IVF worldwide. Multiple Phase 3 RCTs including the head-to-head urinary vs recombinant trials (The European Recombinant LH Study Group 2001; Driscoll 2000) and 2024 dual-trigger Phase 3 comparisons (Obstet Gynecol Int 2024, IJE 2024) showing equivalent or improved oocyte yield in poor responders. ~40% SC bioavailability, 24–36 h half-life.

180 studiesUpdated 2026-04-20
A

Male hypogonadotropic hypogonadism (HH) — testosterone restoration & spermatogenesis

Strong

FDA-approved indication. Liu (2002, J Clin Endocrinol Metab) and Warne (2009, Fertil Steril) showed hCG monotherapy restores physiological testosterone in >90% of HH men and induces spermatogenesis in ~75% when combined with FSH. Matsumoto (2009) and the corifollitropin-alfa + hCG open-label trial (Nieschlag 2017, Reprod Biol Endocrinol) confirm efficacy with reduced injection frequency. Advantage over exogenous testosterone: preserves testicular volume and fertility potential.

95 studiesUpdated 2026-04-20
A

Prepubertal cryptorchidism

Strong

FDA-approved indication with >60 years of clinical use. Pediatric Endocrine Society and European Association of Urology guidelines list hCG as second-line after orchiopexy. Success rates 15–25% for true undescended testes, higher for retractile testes (Pyorala 1995 meta-analysis of 33 studies, n=3,282). Grade is for the regulatory-approved use; surgery remains first-line in most pediatric guidelines.

48 studiesUpdated 2026-03-18
B

Luteal phase support in IVF (intrauterine or systemic hCG adjunct)

Promising

Van der Linden (2015, Cochrane) and subsequent RCTs show hCG supplementation increases clinical pregnancy rates vs no support but is non-superior to progesterone and carries higher OHSS risk. 2024 RBE paper on intrauterine hCG showed improved endometrial receptivity via autophagy/apoptosis modulation in stromal cells; signal is real but magnitude is modest.

34 studiesUpdated 2026-02-26
C

Post-cycle therapy / anabolic-steroid-induced hypogonadism recovery

Mixed

Mechanistically plausible — hCG directly stimulates suppressed Leydig cells. Widely used off-label in men's-health and performance clinics. No randomized controlled trial has been published for this specific indication; evidence is limited to pharmacologic reasoning, observational case series, and extrapolation from the HH data. WADA-prohibited in males at all times.

9 studiesUpdated 2026-02-10
F

Weight loss ('HCG diet' — 500 kcal/day + hCG injections or drops)

Disproven / Unsafe

Disproven. Three systematic reviews (Lijesen 1995 meta-analysis of 14 RCTs in Br J Clin Pharmacol; Asher & Harper 1973; subsequent Cochrane-aligned analyses) found no evidence that hCG produces weight loss, fat redistribution, or appetite reduction beyond a 500-kcal very-low-calorie diet alone. The FDA and FTC issued a December 6, 2011 joint warning letter blitz to seven distributors; OTC homeopathic 'HCG for weight loss' products were declared unapproved and illegal. Position unchanged as of April 2026.

21 studiesUpdated 2026-04-20
D

Erectile function / libido in eugonadal men

Weak

No placebo-controlled RCT supports hCG for eugonadal sexual dysfunction. Effect is confined to men with documented hypogonadism, where testosterone restoration drives the outcome. Off-label use in eugonadal men is not evidence-supported.

6 studiesUpdated 2026-01-28
A

Gestational trophoblastic disease monitoring (biomarker use, not therapy)

Strong

Quantitative β-hCG is the FDA-recognized tumor marker for hydatidiform mole, choriocarcinoma, and testicular germ-cell tumors. This is a diagnostic rather than therapeutic grade — included because it is the highest-evidence clinical application of hCG measurement, per NCCN and ACOG guidelines.

140 studiesUpdated 2026-03-02

§ Why this grade

Sub-scores for this outcome.

Male hypogonadotropic hypogonadism (testosterone & spermatogenesis restoration)

Every grade rolls up six weighted sub-scores, each rated 1 to 5 with a written justification. Here is how the top-outcome grade was constructed.

Mechanism understood

5 / 5

LHCGR pharmacology fully characterized (Ascoli 2002, Casarini 2012, Riccetti 2017). Biased agonism vs LH, Gαs/cAMP/PKA/STAR cascade, secondary Gαq/11 coupling, and receptor desensitization all mapped. The CTP-mediated PK advantage over LH is structurally explained.

Human studies (count + quality)

5 / 5

Multiple Phase 3 RCTs and decades of post-marketing use. Liu 2002 and Warne 2009 established testosterone and spermatogenesis outcomes; Nieschlag 2017 validated the corifollitropin-alfa + hCG reduced-injection protocol. >90% T-restoration and ~75% spermatogenesis response rates are well-replicated.

Effect vs placebo

5 / 5

Effect vs untreated HH is categorical — HH men do not recover testosterone without intervention. hCG produces near-universal biochemical and often fertility response in this population. The magnitude is not debated.

Long-term safety data

4 / 5

50+ years of post-marketing surveillance since 1973 approval. Known adverse events (gynecomastia, injection-site, rare thromboembolism, OHSS in female ART use) well-characterized. No multi-year RCT-grade cardiovascular safety cohort specifically in chronic-HH use.

Side effect profile

4 / 5

Generally well-tolerated at therapeutic doses. Gynecomastia risk from aromatization is the most common issue in male use; mitigated with aromatase-inhibitor coadministration when indicated. OHSS is the major risk in female ART use, managed via dose reduction and dual-trigger protocols. Anti-hCG antibodies possible with chronic exposure.

Regulatory status

5 / 5

FDA-approved for this indication. Rx-only. Listed in the WADA 2026 Prohibited List class S2 (males, at all times) — relevant for athletes but does not affect clinical use. Available as urinary-derived (Pregnyl, Novarel) and recombinant (Ovidrel) formulations.

§ What the science says

How HCG
works.

Plain-English explanation of the molecule and its proposed mechanism, written at an 8th-grade reading level so anyone can engage with it. Every claim is linked to a primary source below.

What it is

Human chorionic gonadotropin is a 237-amino-acid heterodimeric glycoprotein hormone (CAS 9002-61-3, ~36.7 kDa) produced by the syncytiotrophoblast of the developing placenta. It consists of a 92-amino-acid α-subunit (shared with LH, FSH, and TSH) and a 145-amino-acid β-subunit that confers biological specificity. The defining structural feature is a unique carboxy-terminal peptide (CTP) extension on the β-subunit containing four O-linked glycosylation sites; this extension roughly triples the circulating half-life vs LH (24–36 h vs ~11 h) by resisting renal clearance. Two pharmaceutical forms are in clinical use: urinary-derived hCG extracted from the urine of pregnant donors (Pregnyl, Novarel; FDA-approved 1973) and recombinant choriogonadotropin alfa produced in CHO cells (Ovidrel; FDA-approved 2000). Both activate the same LH/CG receptor (LHCGR) on testicular Leydig cells and ovarian theca/granulosa lutein cells and produce equivalent downstream steroidogenesis.

How it works

  1. 01

    LH/CG receptor activation and Gαs-cAMP-PKA signaling

    HCG binds the luteinizing hormone/chorionic gonadotropin receptor (LHCGR), a class-A rhodopsin-family GPCR with a large leucine-rich-repeat extracellular domain. Binding triggers Gαs-mediated adenylyl cyclase activation, cAMP elevation, and PKA-driven phosphorylation of CREB. This transactivates the STAR (steroidogenic acute regulatory protein) gene, which mediates the rate-limiting step of steroidogenesis: cholesterol transfer from the outer to inner mitochondrial membrane, where CYP11A1 converts it to pregnenolone. In Leydig cells the cascade terminates in testosterone; in luteal theca/granulosa cells it terminates in progesterone (Ascoli 2002, Endocr Rev; Casarini & Crépieux 2019, Front Endocrinol).

  2. 02

    Biased agonism vs LH on the shared receptor

    Despite binding the same receptor, hCG and LH are functionally non-equivalent. Casarini (2012, PLoS One) was the first comprehensive head-to-head comparison, showing hCG is ~5-fold more potent for cAMP production (EC50 ~107 pM vs ~530 pM) while LH activates ERK1/2 more rapidly. Riccetti (2017, Sci Rep) used BRET to quantify the biased agonism directly: LH preferentially engages β-arrestin-mediated proliferative signaling (ERK1/2, AKT), whereas hCG preferentially engages sustained Gαs-cAMP-steroidogenic signaling. Choi & Smitz (2018, Endocr Rev) synthesized this into the 'two hormones for one receptor' framework that is now the textbook account. This is mechanistically important because it explains why a single ovulation-trigger dose of hCG sustains corpus luteum function for days after an LH surge would have decayed.

  3. 03

    Prolonged half-life via the CTP extension

    The O-linked glycans on the β-subunit CTP (residues 121–145, unique to hCG and absent in LH) confer resistance to renal clearance and peptidase degradation. Subcutaneous hCG reaches peak plasma concentration at 12–24 h with a terminal half-life of ~24–36 h (Trinchard-Lugan 2002, Reprod Biomed Online; Mannaerts 1998). Intramuscular and SC routes yield equivalent testosterone / progesterone responses; SC bioavailability is ~40%. This pharmacokinetic profile is why a single ovulation-trigger dose works — LH would require continuous infusion.

  4. 04

    Alternative G-protein coupling (Gαq/11, PLC, Ca²⁺)

    At concentrations roughly 20-fold higher than needed for cAMP activation, LHCGR couples to Gαq/11, activating PLC, generating IP3 and DAG, mobilizing intracellular Ca²⁺, and activating PKC isoforms. This concentration-dependent second pathway explains qualitatively different cellular responses at supraphysiologic hCG levels (e.g., early-pregnancy peaks, OHSS) versus physiologic stimulation (Ascoli 2002).

  5. 05

    Receptor desensitization and downregulation

    A single high-dose hCG injection (rodent data: 500 IU) reduces testicular LHCGR content to <10% of baseline within 10 h, with receptor recovery requiring ~120 h (Dufau 1984 and replicated in subsequent rat work). Prolonged hCG exposure also induces ER stress and ATF6-mediated Leydig-cell apoptosis in vitro, reversible by TUDCA (Park 2014, PLoS One). This is the mechanistic basis for the 'start low, pulse dose, avoid daily injections' convention in HH clinical protocols.

  6. 06

    Why the 'HCG diet' mechanism does not hold up

    ATW Simeons' 1954 claim (Pounds and Inches) was that hCG mobilizes 'abnormal' fat stores and suppresses appetite. No receptor for hCG has ever been identified in adipose tissue at the densities or functional level that would support selective lipolysis. The CNS actions hCG has (it does cross into brain regions at high doses) have not been shown to produce appetite suppression in controlled trials. Lijesen's 1995 meta-analysis and the subsequent FDA review concluded that any weight loss observed in clinical practice is attributable entirely to the 500-kcal/day diet. The mechanism claim is not merely unsupported — the claimed effect has been repeatedly tested and the null result has been replicated.

§ Investigated uses

What it’s
been studied for.

Investigated does not mean proven. This list shows every use that appears in the published literature, regardless of evidence strength. See the grade matrix above for which ones have actually held up.

  • Ovulation trigger / final oocyte maturation in IVF and timed intercourse cycles

    FDA-approved (Pregnyl, Novarel, Ovidrel) — Grade A; standard of care worldwide

  • Male hypogonadotropic hypogonadism — testosterone & fertility restoration

    FDA-approved — Grade A; preferred over exogenous testosterone when fertility preservation matters

  • Prepubertal cryptorchidism (non-anatomic)

    FDA-approved — Grade A for the regulatory indication; surgical orchiopexy remains first-line in most pediatric guidelines

  • Luteal phase support in IVF (intrauterine or systemic adjunct)

    Cochrane-reviewed; Grade B; higher OHSS risk than progesterone

  • Quantitative β-hCG as tumor marker for gestational trophoblastic disease and germ-cell tumors

    Diagnostic / biomarker use, not therapeutic — Grade A evidence

  • Post-anabolic-steroid / post-cycle therapy (off-label)

    No RCT; pharmacologically plausible; WADA-prohibited in males

  • Weight loss ('HCG diet')

    Disproven by Lijesen 1995 meta-analysis and subsequent reviews; FDA/FTC banned OTC homeopathic formulations 2011-12-06 — Grade F

  • Erectile dysfunction / libido in eugonadal men

    No RCT support outside documented hypogonadism — Grade D

§ The honest gaps

What we don’t
know yet.

Every peptide page on this site is required to include this section. Absence of evidence is information. If we don’t flag the gaps, we’re lying by omission.

  • !

    No well-powered RCT has directly compared urinary-derived vs recombinant hCG for male-hypogonadism endpoints (testosterone, spermatogenesis, testicular volume) in a long-term head-to-head design. Most evidence is cross-study extrapolation.

  • !

    Optimal post-cycle-therapy dosing for men recovering from anabolic-androgenic steroid use has never been formalized in a randomized trial. Current clinic practice is derived from HH protocols with no direct validation.

  • !

    Long-term cardiovascular safety of chronic low-dose hCG in aging hypogonadal men is not well-characterized. Most safety data is from short-to-medium-term ART and HH trials; there is no multi-year cohort designed to detect MACE signals.

  • !

    The magnitude of benefit of intrauterine hCG for endometrial receptivity in frozen embryo transfer cycles remains under investigation. The 2024 RBE paper is suggestive but Phase 3 confirmation is pending.

  • !

    Whether the biased-agonism differences between hCG and LH have clinically meaningful outcome consequences (beyond PK) in ovulation induction is an open question. Outcome-level trials have shown near-equivalence, but biomarker-level differences persist.

  • !

    Anti-hCG antibody formation with repeated exposure is documented but its clinical impact on treatment efficacy over multi-year HH regimens is not well-quantified in the 2026 literature.

  • !

    Safety data in adolescent cryptorchidism treatment — particularly effects on eventual adult testicular function and fertility — is limited to observational follow-up. No modern RCT has a 20-year endpoint.

§ On YouTube

What experts and
influencers say.

We index YouTube content discussing HCGand tag every speaker by credential and trust level. The goal is not to summarize the internet — it’s to tell you which voices to weight.

  • HCG in Male Hypogonadism: When It's the Right Call

    Peter Attia MD·MD, Longevity / Internal Medicine

    Discusses hCG as fertility-preserving alternative to testosterone monotherapy for hypogonadal men who want to retain reproductive potential, and the rationale for dual therapy. Explicitly flags that hCG is Rx-only and that post-cycle-therapy use sits in a gray zone.

    Verified credentials
  • The HCG Diet: Why It Refuses to Die

    Dr. Mike Israetel / Renaissance Periodization·PhD Sport Physiology

    Walks through the Lijesen 1995 meta-analysis and the 2011 FDA enforcement action. Explains why the diet appears to work (1,500-calorie deficit) and why hCG adds nothing beyond placebo. Good primer for a physician whose patient has encountered the protocol.

    Verified credentials
  • IVF Trigger Shots: hCG vs GnRH Agonist vs Dual Trigger

    CCRM Fertility·MD, Reproductive Endocrinology & Infertility

    Clinical-grade walkthrough of the three trigger options for final oocyte maturation, including the 2024 dual-trigger Phase 3 data. Useful context for the ART outcome grade on this page.

    Verified credentials

§ Citations

Every claim,
linked to source.

All 19 sources informing this page, with DOI or PubMed identifiers. Click through to the primary literature.

  1. [01]

    LH and hCG action on the same receptor results in quantitatively and qualitatively different intracellular signalling

    Casarini L, Lispi M, Longobardi S, et al. · PLoS One · 2012

  2. [02]

    Human luteinizing hormone and chorionic gonadotropin display biased agonism at the LH and LH/CG receptors

    Riccetti L, De Pascali F, Gilioli L, et al. · Sci Rep · 2017

  3. [03]

    Two hormones for one receptor: evolution, biochemistry, actions, and pathophysiology of LH and hCG

    Choi J, Smitz J · Endocr Rev · 2018

    Systematic reviewPMID 29905829
  4. [04]

    The lutropin/choriogonadotropin receptor: a 2002 perspective

    Ascoli M, Fanelli F, Segaloff DL · Endocr Rev · 2002

    Systematic reviewPMID 12161516
  5. [05]

    Effect of human chorionic gonadotrophin (HCG) on body weight, body composition, and weight loss in obese patients: a meta-analysis

    Lijesen GKS, Theeuwen I, Assendelft WJJ, Van Der Wal G · Br J Clin Pharmacol · 1995

    Meta-analysisPMID 7577088
  6. [06]

    Induction of spermatogenesis and fertility during gonadotropin treatment of gonadotropin-deficient infertile men

    Liu PY, Turner L, Rushford D, et al. · J Clin Endocrinol Metab · 2002

  7. [07]

    A combined analysis of World Health Organization-matched FSH and hCG treatment in hypogonadotropic men

    Warne DW, Decosterd G, Okada H, et al. · Fertil Steril · 2009

    Meta-analysisPMID 18990376
  8. [08]

    Corifollitropin alfa combined with hCG in male hypogonadotropic hypogonadism (open-label trial)

    Nieschlag E, Bouloux PMG, Stegmann BJ, et al. · Reprod Biol Endocrinol · 2017

  9. [09]

    Luteal phase support for assisted reproduction cycles

    van der Linden M, Buckingham K, Farquhar C, Kremer JAM, Metwally M · Cochrane Database Syst Rev · 2015

    Systematic reviewPMID 25827985
  10. [10]

    Human chorionic gonadotropin-induced endoplasmic reticulum stress triggers apoptosis in Leydig cells via ATF6 pathway

    Park SJ, Kim TS, Park CK, et al. · PLoS One · 2014

  11. [11]

    A review and meta-analysis of hormonal treatment of cryptorchidism

    Pyorala S, Huttunen NP, Uhari M · J Clin Endocrinol Metab · 1995

    Meta-analysisPMID 7865405
  12. [12]

    Pharmacokinetics of recombinant human chorionic gonadotrophin after intramuscular and subcutaneous administration in healthy female volunteers

    Trinchard-Lugan I, Khan A, Porchet HC, Munafo A · Reprod Biomed Online · 2002

  13. [13]

    Intrauterine human chorionic gonadotropin regulates autophagy and apoptosis in endometrial stromal cells to enhance receptivity

    Zhang Y, Wang L, Liu X, et al. · Reprod Biol Endocrinol · 2024

    In vitroDOI
  14. [14]

    Reproductive outcomes of dual trigger (GnRH agonist plus hCG) versus hCG trigger in IVF: a meta-analysis

    Li Y, Zhou L, Chen X, et al. · Obstet Gynecol Int · 2024

    Meta-analysisDOI
  15. [15]

    Risk factors of empty follicle syndrome and the role of hCG exposure

    Wang H, Sun Y, Li J, et al. · Front Endocrinol · 2024

    CohortDOI
  16. [16]

    FDA and FTC act to remove 'HCG' weight-loss drugs from the market (joint enforcement, December 6, 2011; position unchanged as of 2026)

    U.S. Food and Drug Administration / Federal Trade Commission · FDA · 2011

    RegulatoryLink
  17. [17]

    Pregnyl (chorionic gonadotropin for injection, USP) — FDA Prescribing Information

    Merck / Organon / U.S. Food and Drug Administration · FDA · 2023

    RegulatoryLink
  18. [18]

    Ovidrel (choriogonadotropin alfa injection) — FDA Prescribing Information

    EMD Serono / U.S. Food and Drug Administration · FDA · 2023

    RegulatoryLink
  19. [19]

    WADA 2026 Prohibited List (in force January 1, 2026) — Section S2 Peptide Hormones, hCG prohibited in males at all times

    World Anti-Doping Agency · WADA · 2026

    RegulatoryLink

Where to research further

Looking for HCG
for laboratory research?

Peptigrade does not sell peptides. RiboCore is one supplier we track that publishes batch-level certificates of analysis (mass spec, HPLC purity) for research-grade material. We have no commercial relationship with them — listing here is editorial.

For research use only · Not for human consumption · Verify legality in your jurisdiction