hCG

What it is

hCG (human chorionic gonadotropin) is a hormone the placenta makes in pregnancy, but its structure lets it act like luteinizing hormone (LH) - the pituitary signal that normally tells the testes to make testosterone. On testosterone replacement therapy, the body senses plenty of testosterone in the blood and shuts off its own LH, so the testes go quiet, intratesticular testosterone falls, and sperm production and testicular size can decline. hCG stands in for the missing LH signal, keeping the testes producing testosterone from the inside and helping preserve sperm output and volume while a man stays on TRT. It is approved for male hypogonadotropic hypogonadism and undescended testicles in boys; the TRT-adjunct use for fertility/testicular preservation is off-label.

Dose ranges

Study-backed ranges carry a source you can open. Community ranges are widely reported but not clinically established - treat them as what people do, not as advice.

Reconstitution & storage

IMPORTANT - hCG is measured in USP units (equivalent to International Units, IU), NOT milligrams. The numbers above (5,000 and 10,000) are the vial's UNIT content per the Novarel and Pregnyl labels, not a mass in mg - hCG is a large glycoprotein, so a vial holds only micrograms of actual protein but is standardized and dosed by biological activity in USP/IU. Every calculator figure here is IU. The lyophilized powder ships with a separate diluent: the Novarel label directs reconstitution with Bacteriostatic Water for Injection preserved with 0.9% benzyl alcohol, using 1 mL or 10 mL depending on the concentration you want (e.g. a 10,000 IU vial in 10 mL bacteriostatic water = 1,000 IU/mL; in 1 mL = 10,000 IU/mL). Use only bacteriostatic water intended for injection, never plain or tap water.

Tools for hCG

Common stacks

Interactions & cautions

hCG is contraindicated (per the Novarel label) in precocious puberty, prostatic carcinoma or other androgen-dependent neoplasm, prior allergic reaction to hCG, and pregnancy. Because hCG drives the testes to make androgens, the label warns it may induce precocious puberty when used in boys for cryptorchidism - treatment should stop if signs of precocious puberty appear. Since androgens can cause fluid retention, the label advises caution in patients with cardiac or renal disease, epilepsy, migraine, or asthma. Ovarian hyperstimulation syndrome (OHSS) is an ovulation-induction risk in women and is not relevant to male use. This is educational context drawn from the label, not medical advice.

Questions people ask

Sources

1. [1]NOVAREL (chorionic gonadotropin) for injection - FDA Prescribing Information (DailyMed)labelVial strengths 5,000 and 10,000 USP units; reconstitution with Bacteriostatic Water for Injection (0.9% benzyl alcohol) in 1 mL or 10 mL; refrigerate reconstituted solution and use within 30 days; approved male hypogonadotropic hypogonadism dosing (500-1,000 units 3x/week then 2x/week, or 4,000 units 3x/week for 6-9 months) and cryptorchidism dosing; contraindications (precocious puberty, prostate/androgen-dependent neoplasm, pregnancy) and androgen/fluid-retention precautions.
2. [2]PREGNYL (chorionic gonadotropin for injection, USP) - FDA Prescribing Information (DailyMed)labelConfirms the Pregnyl brand name; 10,000 USP units per multiple-dose vial reconstituted with accompanying diluent (water for injection with sodium chloride and 0.9% benzyl alcohol preservative); dosing measured in USP units.
3. [3]Chorionic Gonadotropin for Injection, USP - FDA Prescribing Information (DailyMed)label10,000 USP units per vial reconstituted with Bacteriostatic Water for Injection; refrigerate after reconstitution and discard after 60 days; male hypogonadotropic hypogonadism and cryptorchidism dosing in USP units; warning that hCG-induced androgen secretion may induce precocious puberty and androgen fluid-retention cautions.
4. [4]OVIDREL (choriogonadotropin alfa) injection - FDA Prescribing Information (DailyMed)labelBiphasic (biexponential) pharmacokinetics of hCG: initial half-life 4.5 +/- 0.5 hours and mean terminal half-life 26.5 +/- 2.5 hours after IV dosing; mean terminal half-life about 29 +/- 6 hours and absolute bioavailability about 40% after subcutaneous dosing (recombinant choriogonadotropin alfa).
5. [5]Dose-dependent increase in intratesticular testosterone by very low-dose human chorionic gonadotropin in normal men with experimental gonadotropin deficiency (Roth/Coviello et al., 2010) PMID 20484472studyEstablishes the mechanistic rationale for hCG as a testicular-preservation adjunct: in men with gonadotropin suppression, very low doses of hCG (15, 60, 125 IU every other day) maintained and raised intratesticular testosterone in a dose-dependent manner versus placebo, showing hCG sustains intratesticular testosterone when the pituitary LH signal is absent.