HCG

Also known as: Human Chorionic Gonadotropin, hCG, Chorionic gonadotropin, Pregnyl, Novarel

Evidence: Clinical

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Overview

Urine-derived placental glycoprotein acting on the LH receptor; labeled IM as Pregnyl and Novarel for cryptorchidism, male hypogonadotropic hypogonadism and ovulation induction. TRT use is off-label.

Human chorionic gonadotropin is a placental glycoprotein of an alpha subunit shared with LH, FSH and TSH and a hormone-specific beta subunit. Urine-derived hCG is marketed in the US as Pregnyl (BLA 017692, 1976) and Novarel (BLA 017016, 1974), both intramuscular only, for prepubertal cryptorchidism, selected men with hypogonadotropic hypogonadism, and ovulation induction after gonadotropin pretreatment. Both labels state that hCG has not been shown to help obesity, and a meta-analysis of the Simeons diet trials agreed (Lijesen 1995). Use alongside testosterone therapy rests on a small study showing preserved intratesticular testosterone (Coviello 2005) and is off-label. Vendor research vials are not the labeled products.

Benefits

Leydig-cell testosterone and spermatogenesis support in male hypogonadotropic hypogonadism (FDA-labeled), ovulation trigger (FDA-labeled), intratesticular testosterone maintained during TRT (small human study, off-label), no effect on obesity (label, meta-analysis)

Dosing reference

Research dose: Community range 250 to 500 IU 2 to 3 times weekly alongside TRT (off-label). Label regimens are in the dosing notes.
Reconstitution: 2 mL bacteriostatic water
Common vial sizes: 5000 mg, 10000 mg

Label regimen for selected men with hypogonadotropic hypogonadism (Pregnyl, Novarel), IM only: 500 to 1,000 USP units 3 times a week for 3 weeks, then the same dose twice a week for 3 weeks; or 4,000 USP units 3 times weekly for 6 to 9 months, then 2,000 USP units 3 times weekly for 3 more months. The 250 to 500 IU 2 to 3x weekly range in this record is off-label use alongside TRT; Coviello 2005 tested low doses every other day in healthy men.

Mechanism

hCG acts at the LH/CG receptor with an action the labels describe as virtually identical to pituitary LH, plus a small degree of FSH activity. In the testis it stimulates Leydig cells to make androgens, which can bring about testicular descent where no anatomical block exists; in the ovary it can stand in for the mid-cycle LH surge to trigger ovulation and maintains the corpus luteum (Pregnyl and Novarel labels). In healthy men whose LH was suppressed by testosterone enanthate, low-dose hCG kept intratesticular testosterone near baseline (Coviello 2005). The labels state it has no known effect on fat mobilization, appetite or fat distribution.

Evidence

Clinical: at least one published human trial or an approved drug

Low-dose hCG every other day kept intratesticular testosterone near baseline in healthy men on testosterone enanthate (Coviello et al., 2005)
Subcutaneous self-administered FSH plus hCG induced spermatogenesis in men with hypogonadotropic hypogonadism (Burgués et al., 1997)
Meta-analysis of hormonal treatment of cryptorchidism, including hCG, found modest descent rates (Pyörälä et al., 1995)
Criteria-based meta-analysis of hCG with the Simeons diet found no evidence of added weight loss (Lijesen et al., 1995)
Human-trial status: urinary hCG is approved by the FDA and marketed as Pregnyl (BLA 017692) and Novarel (BLA 017016), IM only; TRT co-therapy is off-label

References

Side effects

Labels (Pregnyl, Novarel): headache, irritability, restlessness, depression, fatigue, edema, gynecomastia, precocious puberty in boys treated for cryptorchidism, injection-site pain, and hypersensitivity reactions including anaphylaxis. With gonadotropin ovulation induction: ovarian hyperstimulation syndrome, ovarian cyst enlargement or rupture, multiple births and arterial thromboembolism. The benzyl alcohol diluent is not for use in newborns.

Storage

Storage: Powder: room temperature, 20 to 25°C (Novarel) or 15 to 25°C (Pregnyl); refrigerate 2 to 8°C after reconstitution
Lyophilized: 24+ months at room temperature
Reconstituted: 30 days refrigerated (Novarel) or 60 days (Pregnyl)

Pharmacology

Half-life: Urinary hCG labels give no half-life. Recombinant hCG (Ovidrel): terminal 29 ± 6 h after 250 mcg SC in healthy women, initial IV phase 4.5 h (Ovidrel label)
Bioavailability: Pregnyl and Novarel are labeled for IM use only. SC absolute bioavailability of recombinant hCG is about 40% in women (Ovidrel label); no SC figure is labeled for urinary hCG.
Molecular weight: 36000 Da

HCG