Hormone Journal

Human chorionic gonadotropin

Also known as: hCG, Pregnyl

Medically reviewed by Hormone Journal Editorial Team · Last reviewed 2026-05-22

Human chorionic gonadotropin (hCG) is a placental hormone that mimics LH, used clinically for ovulation induction, male hypogonadism, and fertility preservation during testosterone therapy.

What it is

Human chorionic gonadotropin (hCG) is a placental glycoprotein hormone whose action is virtually identical to luteinizing hormone (LH), used in Canadian clinical practice for ovulation induction, hypogonadotropic hypogonadism in men, prepubertal cryptorchidism, and — increasingly — as an alternative or adjunct to testosterone therapy to preserve testicular function and fertility. Also known by the brand name Pregnyl (the Canadian-market name for the injectable formulation), hCG is produced naturally by the placenta beginning within days of implantation, which is why it is the hormone detected by pregnancy tests. Serum hCG levels double roughly every 48–72 hours in a healthy early pregnancy, reaching a peak around weeks 8–10 before declining.

In Canada, injectable hCG is available by prescription and is listed on several provincial formularies for fertility indications. Canadian patients accessing hCG for off-label uses — such as testosterone-therapy adjunct or hypogonadism management — typically obtain it through a physician or nurse practitioner referral, with compounded or brand-name formulations dispensed through licensed pharmacies.

Causes and mechanism

hCG is a heterodimeric protein composed of an alpha subunit (shared with LH, FSH, and TSH) and a unique beta subunit that determines its receptor specificity. It binds the LH/hCG receptor on Leydig cells in the testes, stimulating testosterone and androgen production, and on the corpus luteum in the ovary, stimulating progesterone secretion.

Because hCG mimics LH, it preserves the hypothalamic-pituitary-gonadal (HPG) axis signalling pathway that exogenous testosterone suppresses. Men on testosterone replacement therapy (TRT) experience suppression of endogenous LH, which causes testicular atrophy and impairs spermatogenesis. Co-administration of hCG at doses typically ranging from 500–1,500 IU two to three times per week can maintain intratesticular testosterone and testicular volume during TRT.

Symptoms and diagnosis

hCG itself is not a condition — it is a hormone and a medication. Clinicians measure serum beta-hCG to:

  • Confirm and date early pregnancy
  • Monitor for ectopic pregnancy or miscarriage (serial levels)
  • Screen for gestational trophoblastic disease or certain germ-cell tumours (where hCG is a tumour marker)
  • Assess HPG axis function in men with suspected hypogonadotropic hypogonadism

In Canada, beta-hCG testing is available through LifeLabs, Dynacare, and hospital laboratory networks, generally covered under provincial health insurance when ordered for a medically indicated reason.

Common clinical indications at a glance

IndicationPopulationTypical dose range
Ovulation induction (IVF trigger)Women undergoing ART5,000–10,000 IU IM/SC, single dose
Hypogonadotropic hypogonadismMen1,000–2,000 IU IM/SC, 2–3×/week
CryptorchidismBoys aged 4–9500–1,000 IU IM, 3×/week × 3–6 weeks
Fertility preservation on TRTMen500–1,500 IU SC, 2–3×/week
hCG monotherapy (off TRT)Men post-TRT500–1,000 IU SC, 3×/week

Treatment options

In women: hCG is used as an "ovulation trigger" in assisted reproductive technology (ART) cycles, administered after follicular maturation has been confirmed by ultrasound and estradiol levels. It is typically given as a single injection of 5,000–10,000 IU intramuscularly or subcutaneously, with egg retrieval or timed intercourse scheduled 34–36 hours later. It is used alongside gonadotropins such as FSH (follitropin alfa) and menotropins. The main risk is ovarian hyperstimulation syndrome (OHSS), which occurs in roughly 1–2% of stimulated cycles in severe form and can cause ascites, pleural effusion, and electrolyte disturbances.

In men: For hypogonadotropic hypogonadism, hCG monotherapy stimulates endogenous testosterone production and can restore or maintain spermatogenesis — an advantage over exogenous testosterone, which suppresses sperm production. A 2022 study in Andrology (PMC9271319) found hCG monotherapy to be a safe and effective alternative to traditional testosterone therapy in men with prior exogenous testosterone use, with testosterone levels normalizing in the majority of participants. For men on TRT who wish to preserve fertility or testicular volume, hCG is commonly co-prescribed.

In boys: hCG is used to treat prepubertal cryptorchidism (undescended testes) not caused by anatomical obstruction, typically in children aged 4–9. Testicular descent is often temporary, and surgical orchiopexy may still be required.

What hCG does NOT do: Despite widespread off-label marketing, hCG has no demonstrated effect on fat mobilization, appetite, or body fat distribution. Health Canada and the FDA both state there is no evidence supporting hCG for weight loss, and its use for this purpose is not approved.

When to see a clinician in Canada

Consult a physician, endocrinologist, or reproductive endocrinologist if you are:

  • A woman undergoing fertility treatment who has not ovulated with clomiphene alone
  • A man with confirmed hypogonadotropic hypogonadism seeking to preserve fertility while treating low testosterone
  • A man on TRT experiencing testicular atrophy or planning to conceive
  • A parent of a boy with undescended testes

Canadian patients can access hCG prescriptions through fertility clinics, urologists, endocrinologists, and — for some off-label uses — through telehealth platforms such as Felix, Maple, Phoenix, or Cleo, subject to provincial prescribing regulations. Coverage varies: fertility indications are covered under provincial programs in Ontario (OHIP+ for some ART), Quebec, and Manitoba, but coverage for male hypogonadism indications is inconsistent across provinces.

Limitations and open questions

Research is still emerging on several aspects of hCG use. The optimal dosing protocol for hCG co-administration during TRT — including whether continuous or intermittent dosing better preserves spermatogenesis — has not been established by large randomized controlled trials. Long-term safety data for hCG monotherapy as a testosterone-replacement strategy in men are limited to observational studies and small cohorts. The impact of hCG on cardiovascular risk markers, compared to conventional TRT, remains under investigation.

Health Canada has not issued specific guidance on hCG use for fertility preservation in men on TRT; clinicians rely on Endocrine Society and Canadian Urological Association recommendations, which themselves acknowledge evidence gaps. The role of recombinant LH versus urinary-derived hCG as an ovulation trigger in ART is an active area of comparative research, with no definitive superiority established for either agent. Patients considering hCG for any indication should discuss the evidence base and off-label status with a licensed clinician.

FAQs

How is hCG different from testosterone therapy for low T in men?

Testosterone therapy replaces the hormone directly but suppresses the hypothalamic-pituitary-gonadal axis, causing the testes to stop producing testosterone and sperm on their own — testicular volume can decrease by 25–50% over time. hCG works by mimicking LH to stimulate the testes to produce testosterone endogenously, preserving testicular size and spermatogenesis. A 2022 study found hCG monotherapy normalized testosterone levels in the majority of men who had previously used exogenous testosterone. For men who want to maintain fertility, hCG is often preferred or added to TRT.

Is hCG covered by provincial health insurance in Canada?

Coverage depends on the indication and province. In Ontario, Quebec, and Manitoba, hCG for fertility treatment (such as ovulation induction in IVF cycles) may be partially covered under provincial ART funding programs, though drug costs are often separate from procedure coverage. For male hypogonadism or TRT-adjunct use, provincial drug benefit coverage is inconsistent and often requires special authorization. Patients should confirm coverage with their provincial drug benefit program or a pharmacist before starting treatment.

Can hCG be used for weight loss?

No. Health Canada and the FDA both state that hCG has no demonstrated effect on fat mobilization, appetite, or body fat distribution. The Pregnyl prescribing information explicitly notes that 'hCG has no known effect on fat mobilization, appetite or sense of hunger, or body fat distribution.' Any weight loss seen in hCG 'diet' programs is attributable to the accompanying severe caloric restriction, not the hormone itself. Using hCG for weight loss is not an approved indication and carries risks without proven benefit.

What are the main risks of hCG treatment?

In women, the most serious risk is ovarian hyperstimulation syndrome (OHSS), which occurs in severe form in roughly 1–2% of stimulated ART cycles and can cause abdominal pain, bloating, fluid accumulation, and in rare cases, blood clots or kidney injury. In men, hCG can cause gynecomastia (breast tissue growth) because elevated testosterone is aromatized to estrogen; this occurs in a minority of patients and is dose-dependent. Other reported effects include injection-site reactions, headache, and mood changes. Multiple pregnancies are a risk when hCG is used alongside gonadotropins for ovulation induction.

How is hCG tested for in Canada, and what do the results mean?

Serum beta-hCG is measured through a standard blood test available at LifeLabs, Dynacare, and hospital labs across Canada, typically covered by provincial health insurance when ordered for a medical indication. In early pregnancy, levels below 5 IU/L are considered negative; values above 25 IU/L confirm pregnancy, and levels should roughly double every 48–72 hours in a healthy intrauterine pregnancy. Plateauing or falling levels may indicate miscarriage or ectopic pregnancy. Elevated hCG in non-pregnant individuals can signal gestational trophoblastic disease or certain germ-cell tumours and warrants further investigation.

Sources

All glossary termsUpdated 2026-05-22