FDA Approved Growth Hormone Axis

HCG

also known as: human chorionic gonadotropin, Pregnyl, Novarel, Ovidrel, choriogonadotropin alfa

An FDA-approved fertility and hypogonadism medication commonly discussed in peptide and TRT communities for post-cycle recovery and testicular preservation during testosterone therapy.

A 237-amino-acid heterodimeric glycoprotein hormone with an alpha subunit shared with LH/FSH/TSH and a unique beta subunit that allows LH-receptor-mediated stimulation of testicular Leydig cells or ovarian corpus luteum.

Mechanism of action

Binds LH/CG receptors on ovarian theca and granulosa cells (triggering ovulation at the preovulatory follicle) and testicular Leydig cells (stimulating endogenous testosterone production). In men on exogenous testosterone, HCG preserves testicular volume and intratesticular testosterone by directly stimulating Leydig cells despite suppressed endogenous LH.

Primary uses

Ovulation induction in assisted reproduction
Male hypogonadotropic hypogonadism
Pediatric cryptorchidism
Off-label: testicular preservation during TRT, post-cycle recovery in anabolic steroid discontinuation

Typical dosing

250–5000 IU varies by indication (subcutaneous or intramuscular)

Ovulation trigger: single 5,000–10,000 IU dose or 250 mcg recombinant. Male hypogonadism: 500–2,000 IU 2–3× weekly. TRT adjunct (off-label): 250–500 IU 2–3× weekly.

Regulatory status

FDA-approved: female infertility (ovulation induction as adjunct to gonadotropin stimulation), prepubertal cryptorchidism not due to anatomic obstruction, male hypogonadotropic hypogonadism. Brands: Pregnyl and Novarel (urinary-derived), Ovidrel (recombinant choriogonadotropin alfa).

References

[fda-pi] Pregnyl (chorionic gonadotropin) Prescribing Information. Organon.
[fda-pi] Ovidrel (choriogonadotropin alfa) Prescribing Information. EMD Serono.
[pubmed] Coviello AD, et al. "Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression." J Clin Endocrinol Metab, 2005;90:2595-2602.

Related peptides

Kisspeptin-10

A short active fragment of human kisspeptin — under active clinical investigation for hypothalamic amenorrhea, infertility, and low libido in men and women.

Kisspeptin-54

The full-length endogenous kisspeptin, with the most advanced clinical data as an alternative ovulation trigger in IVF that markedly reduces ovarian hyperstimulation syndrome (OHSS) risk.

Somatropin (HGH)

FDA-approved recombinant human growth hormone — the direct hormone replacement, with multiple clinical indications, prescription-only status, and specific federal criminal provisions against off-label distribution.

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.