hCG
Also known as Human chorionic gonadotropin, Chorionic gonadotrophin, Choriogonadotropin alfa, Novarel, Pregnyl, Ovidrel
Placental hormone acting on the LH receptor; licensed for fertility, used off-label alongside testosterone.
At a glance
- Category
- Hormonal & sexual
- Status
- approved drug
- Made from
- human-derived The conventional product (Pregnyl and generics) is purified from the urine of pregnant women. Choriogonadotropin alfa (Ovidrel) is a recombinant alternative expressed in cultured mammalian cells.
- Route
- intramuscular for the urinary-derived product per label; subcutaneous for recombinant choriogonadotropin alfa and in most off-label practice
- Half-life
- biphasic in humans; roughly 11 hours initial phase and 24-36 hours terminal phase after intramuscular injection
- Onset
- ovulation roughly 36 hours after a trigger dose; testosterone rises within 24-48 hours; testicular volume responses take weeks to months
- Molecular weight
- approximately 36,700 g/mol
- Sequence
- Not a short synthetic peptide: a heterodimeric glycoprotein of a 92-amino-acid alpha subunit (shared with LH, FSH and TSH) and a hormone-specific 145-amino-acid beta subunit, heavily glycosylated
Approved in the US and EU. Urinary-derived chorionic gonadotropin (Novarel, Pregnyl and generics) is indicated for prepubertal cryptorchidism not due to anatomic obstruction, selected cases of hypogonadotropic hypogonadism in males, and induction of ovulation in anovulatory infertile women pretreated with menotropins 1. Recombinant choriogonadotropin alfa (Ovidrel) is approved as an ovulation trigger. US labelling for the urinary product carries a mandatory statement, in capitals, that hCG has not been demonstrated to be effective adjunctive therapy in the treatment of obesity and that there is no substantial evidence it increases weight loss beyond that from caloric restriction 1. Extensive off-label use exists in testosterone-replacement and post-cycle protocols; much of the material circulating outside pharmacies is not pharmaceutically manufactured.
Doping status: Prohibited in males (WADA S2.2.1)
Checked against the WADA 2026 Prohibited List. For a specific product and country, Global DRO is the lookup athletes are expected to use — the List names substances, not brand names.
Two different products sit behind the same name: one is a purified fraction of pooled human urine, the other contains no human-derived material. They are also dosed differently, in units versus micrograms.
Mechanism of action
hCG is produced by the syncytiotrophoblast of the placenta and is structurally close enough to luteinizing hormone that it binds and activates the same receptor, the LHCGR. Downstream signalling is via Gs and cyclic AMP, driving steroidogenesis. In men this means direct stimulation of the Leydig cells to produce testosterone; in women it sustains the corpus luteum and its progesterone output. The label description that hCG action is 'virtually identical to that of pituitary LH' is the practical summary, with a small degree of FSH-like activity as an additional note.
The pharmacokinetic difference from LH is what makes hCG useful. Endogenous LH has a half-life of roughly 20-30 minutes; hCG's terminal half-life is measured in tens of hours, largely because of its heavy sialylated glycosylation, which slows renal clearance. A single injection therefore produces a long, flat LH-receptor stimulus rather than a pulse. That is exactly what is wanted for an ovulation trigger, and it is why hCG can support Leydig cell function in men whose own gonadotropins are suppressed.
The off-label rationale in testosterone protocols follows directly from this. Exogenous testosterone suppresses hypothalamic GnRH and pituitary LH and FSH, which removes the LH signal to the testis. Intratesticular testosterone concentrations, which are 50-100 times serum levels and are required for spermatogenesis, then collapse even though serum testosterone looks normal. hCG substitutes for the missing LH signal at the Leydig cell. It does not replace FSH, so it addresses only one arm of the two-hormone requirement for full spermatogenesis.
hCG has no established action on fat metabolism. There is no receptor mechanism by which it would mobilise adipose tissue, suppress appetite or redistribute body fat, and the FDA-approved labelling states this explicitly.
What the research shows
Evidence for the licensed indications is solid and decades old: hCG as an ovulation trigger and as Leydig-cell stimulation in hypogonadotropic hypogonadism are standard, guideline-supported practice. Evidence for the widespread off-label use during testosterone therapy is real but thinner, resting largely on one small physiological dose-ranging study and one retrospective cohort. Evidence that hCG aids weight loss is absent, and this has been tested and rejected repeatedly.
Research in humans
Ovulation triggering with 5,000-10,000 units after gonadotropin stimulation is established practice in assisted reproduction. In men with hypogonadotropic hypogonadism, hCG alone or with FSH restores testosterone and, over months, spermatogenesis. For concurrent use with testosterone: Coviello and colleagues (2005) gave healthy men testosterone enanthate plus 125, 250 or 500 IU hCG every other day and measured intratesticular testosterone directly by testicular aspiration, showing that even low-dose hCG largely preserved it 2. Hsieh and colleagues (2013) reported a retrospective series in which men on testosterone replacement with concomitant hCG 500 IU every other day maintained semen parameters 3. Neither is a large randomised trial with fertility outcomes. For obesity, the criteria-based meta-analysis by Lijesen and colleagues (1995) found no evidence that hCG produces weight loss, fat redistribution, reduced hunger or improved well-being beyond the severe calorie restriction it is packaged with.
Animal and lab research
Animal work established the Leydig cell and corpus luteum mechanism and the dependence of spermatogenesis on intratesticular testosterone. hCG is also used routinely in veterinary reproduction. These data support the mechanism rather than any specific human protocol.
Caveats. The key human study on concurrent use had a small sample of healthy volunteers and measured intratesticular testosterone as a surrogate, not pregnancies. The supporting clinical series is retrospective and single-centre. Long-term safety of years of continuous hCG alongside testosterone has not been studied prospectively. Urinary-derived products vary in purity between manufacturers, and non-pharmaceutical material sold for research use is of unknown content and potency.
What it is used for
- Ovulation trigger in controlled ovarian stimulation and assisted reproduction
- Selected cases of hypogonadotropic hypogonadism in males 1, to induce testosterone production and, with FSH, spermatogenesis
- Prepubertal cryptorchidism not due to anatomic obstruction 1
- Off-label alongside testosterone replacement to preserve testicular volume and spermatogenesis, or as part of post-cycle protocols intended to restart the gonadal axis after androgen use
- Marketed for weight loss as the 'hCG diet' — a criteria-based meta-analysis found no scientific evidence that hCG causes weight loss, redistributes fat, reduces hunger or improves well-being 4, and approved products must carry a statement saying so 1
Dosing
- Label regimens for hypogonadotropic hypogonadism include 500-1,000 units three times weekly for three weeks then twice weekly for three weeks, and 4,000 units three times weekly for 6-9 months followed by 2,000 units three times weekly for three months 1.
- Label regimens for prepubertal cryptorchidism include 4,000 units three times weekly for three weeks, 5,000 units every second day for four injections, 500-1,000 units for 15 injections over six weeks, or 500 units three times weekly for four to six weeks 1.
- Ovulation induction, urinary-derived hCG, intramuscular: 5,000-10,000 units as a single trigger, one day after the last dose of menotropins 1.
- Recombinant choriogonadotropin alfa is a different product and is dosed by mass, not by units: 250 micrograms subcutaneously, which is roughly equivalent to 6,500 units. That equivalence holds for this product only. It is the one place on this page where a microgram figure appears, and it is not a conversion factor that can be applied to the urinary-derived product.
- The 250-500 unit doses used alongside testosterone come from the Coviello dose-ranging study and from clinical practice, not from a regulatory-approved regimen for that purpose. Higher doses raise oestradiol through increased aromatisable substrate and increase the chance of gynaecomastia and Leydig cell desensitisation.
- Post-cycle protocols circulating in bodybuilding communities use substantially higher doses over short periods. These are not derived from clinical trials, and hCG stimulates the testis directly without restoring hypothalamic or pituitary function — it does not by itself restart the axis it is meant to restart.
- The 'hCG diet' pairs injections or oral drops with a 500 kcal per day intake. Any weight lost is attributable to the starvation diet 4. Oral and homeopathic hCG products are not approved for any indication.
These figures describe what the literature and published protocols report. They are not advice and not a dosing instruction.
Protocols
Novarel (ovulation induction)
approved product informationSource: NOVAREL (chorionic gonadotropin for injection, USP) prescribing information, DailyMed
| One day after the last dose of menotropins | 5,000 to 10,000 units intramuscularly, as a single dose |
|---|
A single trigger dose given when the follicles are judged mature; it is withheld if the ovaries are abnormally enlarged, because that is the setting in which ovarian hyperstimulation syndrome develops. Recombinant choriogonadotropin alfa is dosed by mass instead - 250 mcg subcutaneously, roughly equivalent to 6,500 units - so the numbers do not transfer between products.
Novarel (hypogonadotropic hypogonadism in males)
approved product informationSource: NOVAREL (chorionic gonadotropin for injection, USP) prescribing information, DailyMed
| Regimen 1, weeks 1-3 | 500 to 1,000 units intramuscularly three times weekly |
|---|---|
| Regimen 1, weeks 4-6 | the same dose twice weekly |
| Regimen 2, first 6 to 9 months | 4,000 units three times weekly |
| Regimen 2, following 3 months | reduced to 2,000 units three times weekly |
Two alternative label regimens, not one sequence. The longer, higher-dose regimen is the fertility-directed one; hCG substitutes for LH only, so where spermatogenesis is the goal FSH is generally added once testosterone has normalised.
Novarel (prepubertal cryptorchidism)
approved product informationSource: NOVAREL (chorionic gonadotropin for injection, USP) prescribing information, DailyMed
| Regimen A, 3 weeks | 4,000 units intramuscularly three times weekly |
|---|---|
| Regimen B, 8 days | 5,000 units every second day, four injections in total |
| Regimen C, 6 weeks | 500 to 1,000 units, 15 injections over the six weeks |
Three alternative label regimens for the same indication. Treatment is stopped if signs of precocious puberty appear, and hCG has no role where the problem is anatomical rather than hormonal.
Alongside testosterone replacement (off-label)
user protocol — not validatedSource: Pattern widely followed in TRT practice and among users
This is not a validated schedule. It is a pattern that circulates among users and sellers, reproduced because it is what people actually follow — not because it has been tested. No trial established these doses, this interval or this duration, and nobody is checking what is in the vial. Treat every number below as an assertion, not a finding.
| Ongoing, for as long as testosterone is taken | 250 to 500 units subcutaneously two to three times weekly, or every other day |
|---|
The 250-500 unit figure traces back to a dose-ranging study of intratesticular testosterone during exogenous testosterone administration, not to any approved regimen for this purpose. Larger doses add aromatisable substrate rather than benefit, raising oestradiol and the chance of gynaecomastia, and sustained high exposure can desensitise the Leydig cells.
Post-cycle restart protocols (off-label)
user protocol — not validatedSource: Pattern circulating in bodybuilding communities
This is not a validated schedule. It is a pattern that circulates among users and sellers, reproduced because it is what people actually follow — not because it has been tested. No trial established these doses, this interval or this duration, and nobody is checking what is in the vial. Treat every number below as an assertion, not a finding.
| Roughly 2-3 weeks, beginning once the last dose of exogenous androgen has cleared | commonly 1,000 to 1,500 units every other day - several times the doses used alongside TRT |
|---|---|
| Afterwards | hCG stopped and a SERM such as tamoxifen or clomifene continued alone |
The reasoning behind this pattern does not hold: hCG acts directly on the Leydig cells and does nothing for hypothalamic or pituitary function, so it cannot by itself restart the axis it is used to restart. Sustained high doses can desensitise the Leydig cells and prolong the recovery they are meant to shorten.
Schedules are reproduced as their source states them. Units, IU and milligrams explains why the figures are not interchangeable between products.
Reconstitution
- Vial sizes
- 5,000 USP units, 10,000 USP units, 250 micrograms (recombinant, prefilled syringe)
- Solvent
- Bacteriostatic water for injection with 0.9% benzyl alcohol, supplied with the vial as 10 mL
- Storage
- Powder at room temperature per the label. Once reconstituted, refrigerate at 2-8 °C and use within 30 days. Recombinant choriogonadotropin alfa prefilled syringes are refrigerated and used immediately.
Worked example
A 5,000 unit vial reconstituted with the supplied 10 mL gives 500 units/mL, so 500 units is 1 mL. Using 5 mL instead gives 1,000 units/mL, and 500 units is then 0.5 mL, or 50 units on a U100 insulin syringe.
Swirl gently rather than shaking; hCG is a large glycoprotein and mechanical agitation promotes aggregation. Do not use plain sterile water for a multi-dose vial — it contains no preservative.
Safety
Side effects
- Injection site pain, redness and swelling 1
- Headache, irritability, restlessness, fatigue and depression 1
- Oedema and fluid retention 1
- Gynaecomastia in males 1, driven by aromatisation of the additional testosterone to oestradiol
- Precocious puberty when used in boys 1
- Ovarian hyperstimulation syndrome in women 1: sudden ovarian enlargement, ascites, dyspnoea and, in severe cases, haemoconcentration and thromboembolism
- Enlargement or rupture of pre-existing ovarian cysts 1
- Multiple pregnancy when used for ovulation induction 1
- Arterial thromboembolism 1
- Hypersensitivity reactions - erythema, urticaria, rash, angioedema, dyspnoea - and anaphylaxis reported with urinary-derived products 1
- With prolonged high-dose use in men: Leydig cell desensitisation and rising oestradiol
- Serious adverse events including pulmonary embolism and cardiac arrest have been reported to FDA in the context of hCG used for weight loss
Do not use if
- Precocious puberty 1
- Prostatic carcinoma or other androgen-dependent neoplasm 1
- Prior allergic reaction to hCG 1
- Known or suspected pregnancy 1
- Uncontrolled thyroid or adrenal dysfunction, or an untreated pituitary tumour, when used for ovulation induction
- Abnormal uterine bleeding of undetermined origin, or an ovarian cyst not due to polycystic ovary syndrome
- Weight loss — not an appropriate use at any dose 1
Interactions
No clinically significant drug interactions are established. Relevant pharmacological interactions are hormonal rather than metabolic: hCG raises testosterone and therefore oestradiol, which is why aromatase inhibitors are often used alongside it in off-label practice, and combining hCG with gonadotropins for ovulation induction markedly increases the risk of ovarian hyperstimulation syndrome and multiple pregnancy. hCG interferes with pregnancy tests for up to two weeks after administration, and prolonged use in men suppresses the diagnostic value of an LH measurement.
Sources
- NOVAREL (chorionic gonadotropin for injection, USP) — full prescribing informationDailyMed, US National Library of Medicine
- Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppressionCoviello AD et al., J Clin Endocrinol Metab, 2005
- Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapyHsieh T et al., Journal of Urology, 2013
- The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysisLijesen GK et al., Br J Clin Pharmacol, 1995
- World Anti-Doping Code International Standard — Prohibited ListWorld Anti-Doping Agency