Gonadorelin // Synthetic GnRH
Synthetic GnRH (gonadotropin-releasing hormone) that maintains pituitary function and fertility during testosterone replacement therapy. The standard of care for preserving LH/FSH signaling, testicular volume, and spermatogenesis when using exogenous testosterone. If you're on TRT and want to keep your HPG axis alive, Gonadorelin is the protocol.
Keeping the HPG axis alive during TRT.
When you inject exogenous testosterone, your pituitary stops producing LH and FSH — it thinks there's enough testosterone already. This causes testicular atrophy and infertility. Gonadorelin provides the GnRH signal that keeps the pituitary active despite the exogenous testosterone.
2–3 times weekly alongside TRT.
Gonadorelin is dosed 2–3 times per week as part of a TRT protocol. The pulsatile nature of the dosing mimics natural GnRH release patterns, which is critical for maintaining proper LH/FSH response.
The standard of care for HPG axis preservation.
Gonadorelin (synthetic GnRH) has been FDA-approved for diagnostic evaluation of pituitary function since the 1970s. Its use as a TRT adjunct for fertility preservation has become the modern standard of care in hormone optimization clinics.
The rationale is straightforward: exogenous testosterone suppresses GnRH → LH/FSH → testicular function. Providing exogenous GnRH (Gonadorelin) maintains the pituitary's response capability and downstream testicular activity despite the negative feedback from TRT.
Clinical experience shows that Gonadorelin maintains testicular volume, preserves spermatogenesis in many patients, and facilitates faster HPG axis recovery if TRT is discontinued. It has largely replaced HCG in many TRT protocols due to availability advantages.
TRT adjunct comparison.
| Compound | Level | Mechanism | Fertility | Status |
|---|---|---|---|---|
| Gonadorelin | Pituitary | GnRH → LH/FSH | Preserves | FDA Diagnostic |
| HCG | Gonadal | LH Mimetic | Preserves (direct) | FDA Approved |
| Kisspeptin-10 | Hypothalamus | KISS1R → GnRH | Theoretical | Research |
| Clomiphene | Pituitary | SERM → LH/FSH | Preserves | Off-label |
What to watch for.
Gonadorelin's side effect profile is manageable with proper protocol adherence. Baseline blood work before starting and periodic monitoring during use is essential.
- Injection site reactions (mild)
- Headache (uncommon)
- Flushing (GnRH pulse response — transient)
- Nausea (rare)
- Generally very well tolerated
- Monitor estradiol — LH stimulation can increase aromatization
- Total and free testosterone
- LH and FSH (primary efficacy markers)
- Estradiol (aromatization monitoring)
- SHBG
- Prolactin
- Semen analysis (if fertility preservation is the goal)
- PSA (prostate screening on TRT)
- Hematocrit/hemoglobin (TRT monitoring)
- Primary use: TRT adjunct for HPG axis preservation
- HCG provides alternative or complementary gonadal stimulation
- Kisspeptin-10 for upstream support (different level)
- AI (aromatase inhibitor) may be needed if estradiol rises
- Essential component of a complete TRT protocol
- Continue during TRT discontinuation for axis recovery
- Lyophilized: refrigerate at 2–8°C
- Reconstituted: refrigerate, use within 14–21 days
- Protect from light
- Do not freeze
- Available through compounding pharmacies
Compounds that complement Gonadorelin.
If you're on TRT without HPG support, you're doing it wrong.
Gonadorelin is not optional on TRT — it's essential. Unsupported testosterone replacement shuts down your pituitary, shrinks your testicles, and stops sperm production. Gonadorelin keeps the entire HPG axis active despite exogenous testosterone, preserving testicular volume, fertility, and the ability to recover if you ever stop TRT. 100–200mcg 2–3x per week is the standard protocol. Pair with HCG for maximum gonadal preservation. Blood work every 8–12 weeks to track LH, FSH, testosterone, and estradiol. This is the standard of care in modern hormone optimization — work with a physician who understands it.
Our free Protocol Guide includes the complete TRT adjunct section — Gonadorelin, HCG, hormonal blood work panels, and tracking templates.