hCG
Placental glycoprotein hormone that acts as an LH-receptor agonist — used clinically as an ovulation trigger in IVF and off-label in men to stimulate endogenous testosterone and preserve fertility during or after exogenous androgen use.
What is hCG?
Human chorionic gonadotropin (hCG) is a 237-amino-acid heterodimeric glycoprotein hormone composed of an alpha subunit (shared with LH, FSH, and TSH) non-covalently linked to a beta subunit nearly identical to the beta subunit of luteinizing hormone. It is produced by the syncytiotrophoblast cells of the placenta during pregnancy — detection of hCG in blood or urine is the basis of every modern pregnancy test — and it binds the same receptor as LH (the LH/hCG receptor, LHCGR). In clinical medicine, hCG has two well-established roles: as a final ovulation trigger in IVF and other assisted reproduction cycles (marketed as Ovidrel/Ovitrelle in its recombinant form, and as Pregnyl and Novarel as urinary-derived preparations), and as an LH-mimetic drug in men to stimulate Leydig-cell testosterone production in hypogonadotropic hypogonadism, delayed puberty, cryptorchidism, and off-label for preserving testicular function and fertility during exogenous testosterone use or after anabolic-androgenic steroid use. It is also a consumer search magnet for a third, entirely different context — the discredited Simeons "hCG diet" for weight loss — which is addressed honestly below but is not supported by controlled trials.
What hCG Is Investigated For
hCG has two clinically legitimate centers of gravity and one persistent consumer myth. The legitimate uses are ovulation induction / IVF trigger in women and Leydig-cell stimulation in men with hypogonadotropic hypogonadism — both with decades of strong evidence and FDA-approved products. Its highest-traffic off-label use is in men on testosterone replacement therapy (TRT) or recovering from anabolic-androgenic steroid cycles: low-dose hCG added to testosterone preserves intratesticular testosterone and sperm production (Coviello et al., 2005; and the 2013 Hsieh et al. analysis showing no patient became azoospermic on concomitant TRT plus 500 IU hCG every other day). The myth is the 1954 Simeons "hCG diet" combining hCG injections with a 500 kcal/day diet — repeatedly tested in placebo-controlled trials and a 1995 criteria-based meta-analysis, all finding hCG no better than placebo; any weight loss comes from the extreme calorie restriction, not the hormone. In 2011 the FDA and FTC jointly moved against over-the-counter "homeopathic hCG" drops and pellets as illegal and fraudulent. Treat legitimate hCG use as an endocrine drug requiring clinician oversight; treat the hCG diet as debunked.
History & Discovery
hCG was identified in the 1920s by Selmar Aschheim and Bernhard Zondek at the Charité in Berlin. Their "A-Z test" — injecting the urine of a suspected pregnant woman into immature female mice and observing ovarian follicular response within days — was the first reliable pregnancy test and the first clear demonstration that a gonad-stimulating substance was present in pregnancy urine. Over the following decades, hCG was purified from pooled pregnancy urine for clinical use, and the sequencing of the alpha and beta subunits in the 1970s (work by Canfield, Ross, and others) established the structural relationship between hCG and LH, FSH, and TSH. Clinical use in the 20th century centered on ovulation induction in combination with gonadotropin therapy for infertility, on cryptorchidism in boys, and on inducing testicular descent and pubertal development in hypogonadotropic hypogonadism. Recombinant choriogonadotropin alfa (Ovidrel / Ovitrelle) was developed by Serono and approved by the FDA in 2000, eliminating the need for pooled urine collection and providing a more consistent potency standard. Urinary-derived preparations — Pregnyl (Organon, now Merck) and Novarel — remain in use, particularly for men's-health indications where the higher total IU count per vial is clinically useful. The Simeons hCG diet emerged in 1954, when British endocrinologist Albert T. W. Simeons published "Pounds and Inches" describing his protocol: daily hCG injections combined with a 500 kcal/day diet for obesity. His claims — that hCG specifically mobilized "abnormal fat," reduced hunger, and reshaped the body — were empirically tested in the decades that followed and repeatedly failed to separate from placebo. A 1976 trial by Stein et al. and a 1990 trial by Bosch et al. both used identical very-low-calorie diets in hCG and placebo arms and found no difference in weight loss; a 1995 criteria-based meta-analysis by Lijesen and colleagues in the British Journal of Clinical Pharmacology concluded there was no scientific evidence that hCG produced weight loss beyond caloric restriction. Despite this, the diet was resurrected in consumer weight-loss clinics in the 2000s and paired with homeopathic hCG drops, pellets, and sprays sold over the counter. In December 2011, the FDA and FTC took joint action, declaring those products illegal and fraudulent and ordering them off the market. The underlying endocrine use of hCG was never in question — only the diet application.
How It Works
hCG is a hormone the placenta makes during pregnancy, and it looks enough like LH — the pituitary hormone that tells the testes and ovaries what to do — that it binds the same receptor. In women undergoing IVF, a single shot of hCG triggers the egg to finish maturing and ovulate. In men, hCG tells the testes to make testosterone and sperm directly, bypassing the brain's signal. That makes it useful when the brain's signal is missing (hypogonadotropic hypogonadism) or has been shut off by exogenous testosterone or steroid use.
hCG is a 237-amino-acid heterodimeric glycoprotein consisting of a 92-amino-acid alpha subunit (shared with LH, FSH, and TSH) and a 145-amino-acid beta subunit homologous to LH-beta but with an additional carboxy-terminal peptide extension bearing four O-linked glycans. This extension slows renal clearance and gives hCG a plasma half-life of roughly 24–36 hours, compared to ~20 minutes for LH. Both hormones bind the LH/choriogonadotropin receptor (LHCGR), a Gs-coupled G-protein-coupled receptor expressed on ovarian theca and granulosa cells, testicular Leydig cells, and corpus luteum. Receptor activation drives adenylyl cyclase, elevates cAMP, activates PKA, and upregulates the steroidogenic cascade — StAR, CYP11A1, CYP17A1, HSD3B, CYP19A1 — producing progesterone and estrogens in the ovary and testosterone in Leydig cells. In women, a pharmacologic hCG dose at late follicular phase substitutes for the endogenous LH surge, triggering oocyte meiotic resumption and ovulation roughly 36 hours later. In men, exogenous hCG acts as a long-acting LH replacement, driving intratesticular testosterone concentrations that support spermatogenesis even when pituitary LH is suppressed by exogenous androgens. Recombinant choriogonadotropin alfa (Ovidrel) and urinary-derived hCG (Pregnyl, Novarel) are pharmacodynamically similar in clinical use, with recombinant product offering more consistent potency and purity.
Evidence Snapshot
Human Clinical Evidence
Extensive across multiple indications. Decades of randomized trials support hCG as an IVF ovulation trigger (Cochrane review of 18 RCTs, 2952 women). Strong evidence for Leydig-cell stimulation in men, including Coviello et al. demonstrating dose-dependent maintenance of intratesticular testosterone and Hsieh et al. (2013) showing preservation of spermatogenesis with 500 IU every other day concomitant with TRT. Multiple placebo-controlled trials (Bosch 1990; Stein 1976) and the 1995 Lijesen meta-analysis confirm hCG is no better than placebo for weight loss.
Animal / Preclinical
Comprehensive. hCG has been used in livestock reproductive biology for decades, and its effect on LHCGR, steroidogenesis, and gonadal function is thoroughly characterized in rodents and larger mammals.
Mechanistic Rationale
Very strong. LHCGR biology, hCG structure, and the pharmacology of LH-receptor agonism are among the most thoroughly mapped areas of reproductive endocrinology.
Forms & Administration
hCG is administered by subcutaneous or intramuscular injection. Recombinant choriogonadotropin alfa (Ovidrel) comes as a pre-filled 250 mcg syringe for a single IVF trigger dose. Urinary-derived hCG (Pregnyl, Novarel) is supplied as a lyophilized powder reconstituted with bacteriostatic water or saline, typically in vial sizes of 5,000 or 10,000 IU. For men on TRT or in PCT, low-dose protocols (commonly 500 IU 2–3 times weekly) use reconstituted vials stored refrigerated and drawn with an insulin-gauge syringe. hCG should only be used under the supervision of a qualified clinician who can select the indication, choose product, and manage monitoring.
Dosing & Protocols
The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.
Typical Range
IVF ovulation trigger: single dose of 250 mcg recombinant choriogonadotropin alfa (Ovidrel) subcutaneously, or 5,000–10,000 IU urinary-derived hCG intramuscularly, given 34–36 hours before planned oocyte retrieval. Male hypogonadotropic hypogonadism: 1,500–5,000 IU 2–3 times weekly by IM or SC injection, often combined with recombinant FSH for fertility induction. TRT adjunct for fertility / testicular preservation: commonly 500 IU SC every other day (the Hsieh/Coviello protocol), sometimes 250–500 IU 2–3 times weekly. Post-cycle therapy after anabolic steroid use: empirical protocols typically 1,000–2,500 IU every other day for 2–4 weeks, often followed by a SERM (clomiphene or tamoxifen) to stimulate recovery of the pituitary signal once the testes have been "primed."
Frequency
IVF trigger is single-dose. Men's-health protocols range from every-other-day (for TRT adjunct) to 2–3 times weekly (for hypogonadism) to once-weekly (some maintenance schedules). Daily dosing is uncommon and generally unnecessary given hCG's 24–36-hour half-life.
Timing Considerations
No specific timing requirements: can be administered at any time of day, with or without food, and is not tied to exercise timing. Consistency matters more than the specific clock — dose at roughly the same time each day (or same day each week, for weekly protocols) to keep exposure steady.
Cycle Length
Ovulation trigger is single-use per cycle. TRT-adjunct use is typically continuous alongside testosterone — the rationale is that exogenous testosterone is ongoing, so the substitution for LH must be ongoing too. Fertility-induction protocols run 3–6 months minimum to allow a full spermatogenic cycle, and often 9–12 months before maximal sperm response. PCT protocols are short (2–4 weeks) and intentionally bounded.
Protocol Notes
Reconstitution of urinary-derived hCG from lyophilized powder typically uses bacteriostatic water; post-reconstitution stability is around 30 days refrigerated for most preparations. Ovidrel ships pre-filled and does not require reconstitution. Subcutaneous administration with an insulin-gauge syringe is standard for low-dose maintenance use; intramuscular is used for trigger doses and some pediatric cryptorchidism protocols. In men, the key titration question is estradiol. hCG-stimulated testosterone aromatizes into estradiol like any other testosterone, and aggressive dosing (2,000+ IU multiple times weekly) reliably raises E2 — sometimes enough to warrant an aromatase inhibitor or a dose reduction. The 500 IU every-other-day protocol is popular specifically because it is aggressive enough to maintain Leydig-cell function without driving E2 out of range in most men. In women undergoing IVF, the dose-response surface has been mapped in detail: 250 mcg recombinant hCG produces equivalent oocyte yield and pregnancy rates to 500 mcg while substantially reducing OHSS risk, so 250 mcg is the standard adult dose. Importantly: over-the-counter "homeopathic" hCG drops, pellets, or sprays marketed for weight loss are not legitimate hCG products. They either contain no hCG (homeopathic dilution) or unregulated amounts, and they were declared illegal by the FDA/FTC in 2011. Anyone considering hCG should work with a clinician using an FDA-approved or legitimately compounded injectable product.
hCG has multiple FDA-approved indications (IVF trigger, hypogonadotropic hypogonadism, cryptorchidism), but its off-label use for TRT adjunct and anabolic-steroid recovery is not FDA-approved. hCG for weight loss is explicitly not FDA-approved and has been the subject of FDA enforcement action. Any use should be under the supervision of a qualified clinician.
Timeline of Effects
Onset
After a single IM or SC injection, serum hCG is detectable within 1–2 hours and peaks at 6–12 hours. Ovulation following an IVF trigger occurs at approximately 36–40 hours, which is why retrieval is timed to 34–36 hours. In men, Leydig-cell testosterone output rises within hours of injection and a single 1,500 IU IM dose can elevate plasma testosterone for 96–120 hours. Subjective effects in hypogonadal men — energy, libido, mood — are typically reported within 1–4 weeks of consistent dosing.
Peak Effect
Acute testosterone peak occurs 48–96 hours after injection in men and plateaus within 4–8 weeks on a stable regimen. Testicular volume recovery in men previously suppressed by TRT or AAS use is typically measurable by 8–12 weeks and continues to improve over 3–6 months. Spermatogenic recovery follows the full spermatogenic cycle — meaningful semen-parameter changes take 3–6 months and maximal response often takes 9–12 months of continuous gonadotropin stimulation.
After Discontinuation
hCG itself clears the system within approximately 7–10 days after the last dose given its 24–36-hour half-life. For men using hCG alongside ongoing TRT, discontinuing the hCG while continuing testosterone returns the user to the trajectory of HPG-axis suppression characteristic of TRT alone — testicular atrophy and reduced spermatogenesis resume over weeks to months. For men discontinuing both hCG and exogenous testosterone, HPG-axis recovery follows the general post-TRT / post-AAS trajectory, with prior hCG use preserving Leydig-cell responsiveness but not altering the pituitary-side recovery timeline.
Common Questions
Who hCG Is NOT For
- •Known hypersensitivity to hCG or to excipients in the specific product — anaphylactoid reactions have been reported.
- •Hormone-sensitive malignancy — prostate cancer, testicular cancer, and certain hormone-sensitive breast cancers, where hCG-driven testosterone or estrogen elevation is contraindicated.
- •Precocious puberty or a known pituitary tumor — hCG stimulation in these contexts requires specialist management, not empirical use.
- •Ovarian cysts or ovarian enlargement not due to polycystic ovary syndrome — risk of further enlargement and rupture.
- •Uncontrolled thyroid or adrenal dysfunction — these axes should be stabilized before reproductive-axis stimulation.
- •Pregnancy — hCG is not indicated as a therapeutic during established pregnancy (it is used pre-conception as an ovulation trigger); exogenous administration during pregnancy is not appropriate.
- •Severe cardiovascular, renal, or hepatic disease — the fluid-shift and hormonal consequences of OHSS in women or testosterone elevation in men may be poorly tolerated.
- •Weight loss — the FDA has explicitly determined hCG is not appropriate therapy for weight loss; this is not a medical contraindication in the narrow sense but is a regulatory one.
Drug & Supplement Interactions
hCG's pharmacodynamic interactions are centered on the reproductive axis. The most important practical interaction is with exogenous testosterone in men: the entire therapeutic rationale of adding hCG to TRT rests on hCG substituting for the suppressed LH signal, and dosing must be calibrated against the TRT dose, frequency, and measured response. Combining hCG with GnRH agonists or antagonists (leuprolide, goserelin, cetrorelix) is generally counterproductive — the GnRH drug is designed to suppress gonadotropin activity, which hCG then partially restores downstream of the block. Aromatase inhibitors (anastrozole, letrozole) are often paired with hCG in men to control the estradiol rise that hCG-driven testosterone production produces; this is standard off-label practice but should be dose-titrated to measured E2. SERMs (clomiphene, tamoxifen, enclomiphene) are frequently combined with hCG in post-cycle therapy and in fertility induction, acting upstream to raise endogenous gonadotropins while hCG acts directly on the Leydig cell. In women undergoing IVF, hCG interacts with the FSH preparation and GnRH antagonist protocol used during stimulation — the interaction is the intended protocol and is managed by the reproductive endocrinologist. Concurrent high-dose glucocorticoids may blunt the hCG-stimulated gonadal response. Drugs known to suppress spermatogenesis independently (cytotoxic chemotherapy, certain antiepileptics, high-dose opioids) may limit the response to hCG in men. hCG interferes with pregnancy-test results because pregnancy tests detect hCG itself — this is a laboratory, not a pharmacologic, interaction but is worth noting for users.
Safety Profile
Common Side Effects
Cautions
- • Ovarian hyperstimulation syndrome (OHSS) is the principal dose-limiting risk in women undergoing IVF — 500 mcg recombinant doses have been associated with higher OHSS rates than 250 mcg
- • In men, hCG raises estradiol via aromatization and may require concurrent aromatase-inhibitor management
- • Contraindicated in hormone-sensitive malignancy (prostate, certain breast cancers, testicular cancer)
- • Over-the-counter "homeopathic hCG" weight-loss products were declared illegal by the FDA/FTC in 2011 — any such products on the market are unauthorized
- • Prohibited by WADA under category S2 for male athletes at all times; female athletes are not subject to the prohibition
- • Compounded hCG product quality varies — prefer FDA-approved products where the clinical context allows
What We Don't Know
Long-term safety of chronic low-dose hCG as a TRT adjunct, over years rather than months, is not well characterized in controlled trials. Optimal hCG dosing for post-cycle recovery after long-term anabolic steroid use remains empirical. Any weight-loss effect of hCG above and beyond calorie restriction has been actively searched for and not found — the honest answer there is not 'unknown' but 'debunked.'
Legal Status
United States
hCG is FDA-approved as multiple prescription products: Ovidrel (choriogonadotropin alfa, recombinant) for IVF ovulation trigger; Pregnyl and Novarel (urinary-derived hCG) for ovulation induction, cryptorchidism, and hypogonadotropic hypogonadism in men. Prescription use is legal under these labels. Off-label use for TRT adjunct and post-cycle therapy is common but not FDA-approved. Over-the-counter "homeopathic" hCG drops, pellets, and sprays for weight loss were declared illegal by the FDA and FTC in 2011 and are subject to seizure and enforcement. hCG is not a controlled substance at the federal level, though some states have specific restrictions.
International
hCG products are approved in essentially every major regulatory jurisdiction for ovulation induction and male hypogonadism indications. EMA-approved products include Ovitrelle (the EU name for Ovidrel), Pregnyl, and various generic urinary preparations. Availability and labeling for cryptorchidism and PCT/TRT-adjunct use varies by country.
Sports & Competition
hCG is prohibited for male athletes at all times (in and out of competition) by WADA under category S2 — peptide hormones, growth factors, related substances and mimetics — because it stimulates endogenous testosterone production. The prohibition does not apply to female athletes, as hCG does not produce a performance-relevant hormonal effect in women. Male athletes subject to WADA code, USADA, UKAD, or equivalent anti-doping bodies must treat hCG as prohibited regardless of therapeutic intent; Therapeutic Use Exemptions are evaluated case by case.
Regulatory status changes over time. Verify current local rules with a qualified professional.
Myths & Misconceptions
Myth
The hCG diet works because hCG specifically burns abnormal fat.
Reality
Repeatedly tested and repeatedly disproven. Placebo-controlled trials (Stein 1976; Bosch 1990) and a 1995 criteria-based meta-analysis (Lijesen et al., British Journal of Clinical Pharmacology) all found hCG no better than saline when both groups ate the same 500 kcal/day diet. The weight loss is entirely from the calorie restriction. The FDA and FTC took joint enforcement action in 2011 declaring over-the-counter "homeopathic hCG" weight-loss products illegal and fraudulent.
Myth
hCG and LH are the same thing.
Reality
They bind the same receptor and produce similar downstream effects, but they are distinct proteins with different pharmacokinetics. hCG has a glycosylated carboxy-terminal extension on its beta-subunit that gives it a plasma half-life of 24–36 hours versus LH's ~20 minutes. That is why a single hCG injection can sustain a Leydig-cell response for days, while LH needs continuous pulsatile secretion.
Myth
Homeopathic hCG drops and pellets are a safer, easier alternative to injections.
Reality
Homeopathic hCG products either contain essentially no hCG (by the definition of homeopathic dilution) or unregulated amounts, and none have demonstrated weight-loss efficacy beyond the accompanying very-low-calorie diet. The FDA and FTC declared them illegal in 2011. Legitimate hCG is an injectable prescription drug.
Myth
hCG causes testicular atrophy.
Reality
The opposite is true. Exogenous testosterone suppresses LH and causes testicular atrophy; hCG mimics LH and maintains or restores testicular volume and function. The Rozati/2015 randomized comparison in late-onset hypogonadism specifically found that hCG patients avoided testicular atrophy while testosterone-treated patients did not.
Myth
hCG is a weight-loss drug.
Reality
hCG has multiple legitimate endocrine indications — ovulation trigger in IVF, hypogonadotropic hypogonadism in men, cryptorchidism in boys — but weight loss is not among them. The FDA explicitly states there is no substantial evidence that hCG produces weight loss beyond the caloric restriction that accompanies it, and hCG is not approved for any weight-loss indication.
Myth
hCG can fully restart natural testosterone after any anabolic steroid cycle.
Reality
hCG can reliably stimulate Leydig cells in the short term and is part of standard PCT protocols, but full recovery of the HPG axis — including pituitary LH and FSH secretion — depends on duration and dose of prior steroid use, baseline testicular reserve, and time. Men who have used high-dose AAS for years may have prolonged or incomplete recovery regardless of hCG or SERM therapy.
Published Research
7 studiesHuman chorionic gonadotropin treatment: a viable option for management of secondary hypogonadism and male infertility
Literature review (1977–2020) on hCG for secondary hypogonadism, including comparison with TRT on hematocrit, estradiol, PSA, and fertility endpoints.
Late-onset hypogonadism: the advantages of treatment with human chorionic gonadotropin rather than testosterone
40 LOH patients randomized to hCG vs. three testosterone formulations over 6 months; hCG avoided testicular atrophy and produced fewer adverse effects on hematocrit and PSA.
Anabolic steroid–induced hypogonadism: diagnosis and treatment
Rahnema et al. 2014 — management review establishing hCG plus SERM as standard approach to anabolic-steroid-induced hypogonadism and fertility recovery.
Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy
Hsieh et al. — 26 men on TRT plus 500 IU hCG every other day; no patient became azoospermic, and 9 contributed to a pregnancy during follow-up.
The effect of human chorionic gonadotropin (hCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis
Lijesen et al. 1995, British Journal of Clinical Pharmacology — criteria-based meta-analysis concluding there is no scientific evidence hCG causes weight loss, redistributes fat, reduces hunger, or induces wellbeing beyond caloric restriction.
Human chorionic gonadotrophin and weight loss. A double-blind, placebo-controlled trial
Bosch et al. 1990 — 40 obese women, 6 weeks, same 5,000 kJ/day diet with hCG vs. saline; no advantage for hCG on weight loss, body measurements, hunger, or wellbeing.
Ineffectiveness of human chorionic gonadotropin in weight reduction: a double-blind study
Stein et al. 1976 — 51 obese women, 32-day double-blind comparison; hCG did not outperform placebo on weight loss or hunger when both groups received identical very-low-calorie diets.
Quick Facts
- Class
- Gonadotropin / LH Receptor Agonist
- Evidence
- Strong
- Safety
- Well-Studied
- Updated
- Apr 2026
- Citations
- 7PubMed
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Clinical Trials
View Clinical TrialsLinks to ClinicalTrials.gov for reference. Listing does not imply endorsement.