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Reviewed by MyPeptideMatch Editorial TeamLast reviewed February 2026Updated February 2026

Gonadorelin Dosing Protocol: 2 mg Vial — TRT Support & LH Pulse Guide

Gonadorelin (GnRH) dosing protocol for maintaining HPG axis function and testicular size during testosterone replacement therapy.

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Quickstart highlights

Gonadorelin is synthetic GnRH (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2), identical to the hypothalamic decapeptide.

  • Concentration: 2 mg/mL (2 mg vial + 1 mL bacteriostatic water).
  • At 2 mg/mL: 100 µg = 5 units, 250 µg = 12.5 units, 500 µg = 25 units.
  • Inject on TRT injection days (2x weekly) to align GnRH pulse with T clearance cycle.
  • Do NOT inject daily — continuous GnRH causes gonadotropin desensitization and paradoxical HPG suppression.
  • One 2 mg vial provides 20 doses at 100 µg — approximately 10 weeks at 2x weekly.

Dosing table

For educational reference only. Your prescribing provider may adjust doses based on your clinical profile and response.

WeekDose (µg)UnitsFrequencyNotes
1+10052x weekly (with TRT injection days)100 µg — 5 units; inject on same days as testosterone (TRT); one 2 mg vial provides 20 doses
alt500252x weekly500 µg — 25 units; higher dose protocol; 4 doses per 2 mg vial

Reconstitution steps

  1. Draw 1 mL bacteriostatic water; inject slowly down the vial wall.
  2. Swirl gently until powder dissolves; do not shake.
  3. Final concentration: 2 mg/mL. At 2 mg/mL: 100 µg = 5 units, 250 µg = 12.5 units.
  4. Label with date; refrigerate at 2–8 °C. Use within 28 days.

Supplies needed

4-week plan

  • 2 vials
  • 8 syringes
  • 2 mL bac water
  • 8 alcohol swabs

12-week plan

  • 6 vials
  • 24 syringes
  • 6 mL bac water
  • 24 alcohol swabs
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Protocol overview & cycle notes

Maintain testicular function, size, and fertility during exogenous testosterone therapy by providing pulsatile GnRH stimulation to preserve LH → Leydig cell testosterone production and FSH → Sertoli cell spermatogenesis.

Off-cycle: Ongoing with TRT; 2 mg vial provides 20 doses at 100 µg — approximately 10 weeks at 2x weekly.

Storage & handling

Lyophilized: store below 25 °C. Reconstituted at 2 mg/mL: refrigerate 2–8 °C; use within 28 days. One 2 mg vial provides 20 doses at 100 µg or 4 doses at 500 µg.

Injection & tracking tips

  • Inject subcutaneously on the same days as your testosterone injection to align pulsatile LH stimulation with peak androgen clearance.
  • Gonadorelin has a very short half-life (2–8 minutes) — effect on the pituitary lasts 2–4 hours post-injection. Once- or twice-weekly dosing provides LH pulses sufficient for testicular stimulation.
  • Do not inject gonadorelin daily — continuous GnRH stimulation causes gonadotropin desensitization and testicular suppression (the mechanism of leuprolide in prostate cancer treatment).

Tracking

Logging helps you and your provider spot patterns and adjust dose or timing.

  • Measure serum LH, FSH, and total testosterone every 8 weeks while on TRT + gonadorelin.
  • Track testicular volume subjectively (or via ultrasound if available) every 3 months to assess for atrophy prevention.
  • Monitor sperm count if fertility preservation is a goal — gonadorelin maintains spermatogenesis during TRT.
Log your cycle in the calculator →

How this works & references

Gonadorelin is synthetic GnRH (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2), identical to the hypothalamic decapeptide. During TRT, exogenous testosterone suppresses the HPG axis via negative feedback, reducing LH and FSH to near-zero — causing testicular atrophy, oligo/azoospermia, and intratesticular testosterone depletion. Pulsatile gonadorelin (100–500 µg subcutaneous 2–3x weekly) maintains LH/FSH pulsatility despite exogenous T, preserving Leydig and Sertoli cell function. Unlike HCG (which directly stimulates Leydig cells), gonadorelin works via the natural LH/FSH pathway, potentially offering more physiological testicular stimulation.

Sources

Frequently asked questions

Is gonadorelin better than HCG for maintaining testicular function on TRT?
Both preserve testicular size and function; they differ in mechanism. HCG directly mimics LH at Leydig cells (bypassing the pituitary). Gonadorelin stimulates pituitary LH and FSH release, maintaining both Leydig (testosterone) and Sertoli (spermatogenesis) cell function — potentially superior for fertility preservation. HCG does not meaningfully stimulate FSH. The choice depends on fertility goals and pituitary responsiveness.
What dose of gonadorelin is needed to prevent testicular atrophy on TRT?
Small studies and clinical experience suggest 100–200 µg subcutaneous 2–3x weekly is sufficient to maintain testicular LH/FSH stimulation and prevent clinically significant atrophy. Some protocols use 500 µg 2x weekly for more robust stimulation, particularly when attempting to maintain fertility.
How does gonadorelin compare to leuprolide?
Gonadorelin and leuprolide (Lupron) are both GnRH receptor agonists, but with opposite clinical outcomes: gonadorelin is given in pulses (short-acting, stimulatory) while leuprolide is given continuously (long-acting, desensitizing → suppression). Leuprolide's continuous action causes HPG axis shut-down used in prostate cancer and endometriosis treatment. Pulsatile gonadorelin stimulates the axis.
Can women use gonadorelin for fertility?
Yes — pulsatile gonadorelin pump therapy (subcutaneous or IV infusion at 90-minute intervals) is used for hypothalamic amenorrhea to induce ovulation and restore the menstrual cycle. This requires medical monitoring of ovarian response. Compounded subcutaneous gonadorelin 2x weekly at 100–500 µg is a simplified approximation used by some fertility specialists.
Is FDA-approved gonadorelin available by prescription?
Factrel (gonadorelin HCl) is FDA-approved for diagnostic testing of LH/FSH reserve. Lutrepulse (gonadorelin acetate) was approved for hypothalamic amenorrhea but is no longer marketed. Compounded gonadorelin for TRT support is available from licensed compounding pharmacies under physician prescription.

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This content is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider before starting any peptide therapy. Dosing and protocols may vary by formulation and prescriber.

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