Gonadorelin for Fertility Preservation on TRT — Testosterone & Androgens
Synthetic GnRH agonist that stimulates pituitary LH and FSH release, used as an alternative to hCG for maintaining fertility during TRT.
Overview
Gonadorelin (also known as GnRH or LHRH) is a synthetic decapeptide identical to endogenous gonadotropin-releasing hormone. When administered in a pulsatile fashion, it stimulates the anterior pituitary to release LH and FSH, maintaining gonadal function. Gonadorelin has gained significant traction in TRT clinics since the 2020 FDA reclassification of hCG as a biologic, which restricted compounding pharmacy production and increased costs. Administered subcutaneously at doses of 100-200 mcg twice daily, gonadorelin provides pulsatile GnRH stimulation that preserves pituitary-gonadal signaling during exogenous testosterone use. While it does not directly stimulate Leydig cells like hCG, the resulting LH secretion maintains intratesticular testosterone and supports spermatogenesis. Clinical evidence for gonadorelin specifically as a TRT adjunct is more limited than for hCG, but its mechanism is well-established from decades of use in diagnostic testing and pulsatile GnRH therapy for hypothalamic amenorrhea and hypogonadotropic hypogonadism.
Indications
- FDA-approved: Diagnostic evaluation of pituitary gonadotroph function
- Off-label: Fertility preservation during TRT (alternative to hCG)
- Off-label: HPG axis maintenance during testosterone therapy
- Off-label: Hypogonadotropic hypogonadism (pulsatile administration)
Mechanism of Action
Binds to GnRH receptors on gonadotroph cells in the anterior pituitary, mimicking endogenous pulsatile GnRH
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Gonadorelin | 100 mcg | Twice daily | Standard TRT adjunct dose |
| Gonadorelin | 200 mcg | Twice daily | Higher dose for suboptimal response |
| Gonadorelin | 50 mcg | Twice daily | Starting dose for sensitive individuals |
| Gonadorelin | 100 mcg | Single dose | GnRH stimulation test (diagnostic use) |
Evidence Grade
GRADE B
Safety & Contraindications
- Injection site reactions (redness, swelling)
- Headache and flushing reported
- Continuous (non-pulsatile) administration paradoxically suppresses LH/FSH — must use pulsatile/intermittent dosing
- Less clinical data as TRT adjunct compared to hCG
- Multiple daily injections may reduce compliance
- Short half-life (~4 minutes IV, longer SC) necessitates twice-daily dosing