MEDICAL DISCLAIMER: Educational research guidelines only. Lyophilized peptides are investigational chemical compounds and are NOT approved for human consumption, diagnosis, or therapy. Consult a licensed physician before any research application.
Gonadorelin Dosage Chart, Schedule & Reconstitution Protocol
Quickstart Highlights
Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), a decapeptide identical to the native hypothalamic releasing factor characterized by Schally and Guillemin in work that earned the 1977 Nobel Prize. Pulsatile gonadorelin administration activates pituitary GnRH receptors on gonadotrophs, driving physiologic release of LH and FSH, which in turn stimulate testicular Leydig and Sertoli cell function in men and ovarian follicular development in women. Continuous or supraphysiologic dosing paradoxically downregulates the receptor and suppresses gonadotropin output [PMID: 6088688]. Gonadorelin is FDA-approved as Factrel for the diagnostic evaluation of hypothalamic-pituitary-gonadal axis function and historically as Lutrepulse (pump-administered) for hypothalamic amenorrhea and male hypogonadotropic hypogonadism. In post-cycle therapy contexts, it is used off-label at subcutaneous microdoses (often 100 to 200 mcg several times daily) to mimic endogenous pulsatility. Plasma half-life is roughly 10 to 40 minutes.
Reconstitute: Add 2 mL bacteriostatic water → 1 mg/mL concentration.
Typical dose: 50–250 mcg per injection, 2–3 times weekly.
Easy measuring: At 1 mg/mL, 1 unit = 0.01 mL = 0.0100 mg (10 mcg) on a U-100 insulin syringe.
Storage: Lyophilized frozen; reconstituted refrigerated; avoid repeated freeze–thaw.
Pulsatile vs continuous dosing: Physiologic LH/FSH release requires GnRH pulses every 60 to 120 minutes. Continuous gonadorelin exposure (or long-acting analogs like leuprolide) instead desensitizes the receptor and suppresses the axis, the basis of GnRH agonist depot therapy.
PCT use is off-label and debated: Gonadorelin's very short half-life means single daily injections cannot reproduce true pulsatility; many PCT protocols inject it 2 to 4 times daily. Compared with hCG, it acts upstream at the pituitary rather than directly on Leydig cells.
FDA approval status: Factrel (gonadorelin acetate) is FDA-approved for diagnostic pituitary function testing. Lutrepulse was discontinued in the US around 2000. Current US use is largely via compounding pharmacies.
Quick Protocol Navigation
Reconstitution Instruction & Mixing Step-by-Step
Lyophilized powder must be reconstituted carefully. Agitating peptide chains can shear disulfide bonds and render the peptide biologically inert.
Draw 2.0 mL bacteriostatic water with a sterile syringe.
Inject slowly down the vial wall; avoid foaming.
Gently swirl/roll until dissolved (do not shake).
Inject slowly; wait a few seconds before withdrawing the needle.
Do not aspirate for subcutaneous injections; inject slowly and steadily[12].
Interactive Gonadorelin Syringe Calculator
Currently visualizing the 2 mg vial reconstituted with 2 mL bacteriostatic water. Adjust the target dose to dynamically render syringe units.
Reconstitution Calculation: 2mg dry powder in 2mL water yields 1.00 mg/mL. To evaluate a 250mcg dose, pull to 25.0 units (25 syringe ticks).
U-100 Syringe Representation
25.0 Units (25 Ticks)
Educational reference visual. Assumes standard U-100 insulin syringe where 1.0 mL volume = 100 units.
Titration & Dose Escalation Schedules
| Week/Phase | Dose per Injection (mcg) | Units (mL) |
|---|---|---|
| Weeks 1–2 (Initiation) | 50 mcg | 5 units (0.05 mL) |
| Weeks 3–4 (Titration) | 100 mcg | 10 units (0.10 mL) |
| Weeks 5–8 (Maintenance) | 100–150 mcg | 10–15 units (0.10–0.15 mL) |
Administration guidelines: Refer to guidelines | 2 mL Reconstitution
| Week/Phase | Dose per Injection (mcg) | Units (mL) |
|---|---|---|
| Days 1–7 (Burst) | 200 mcg | 20 units (0.20 mL) |
| Days 8–14 (Taper) | 100 mcg | 10 units (0.10 mL) |
| Week 3+ (Optional Maintenance) | 100 mcg 2–3×/wk | 10 units (0.10 mL) |
Administration guidelines: Refer to guidelines | 2 mL Reconstitution
Research Supplies Quantity Planner
Scientific mathematical planning of syringes, bacteriostatic water and dry vials needed for extended research blocks using the 2 mg vial.
Peptide Vials (Gonadorelin, 2 mg each):
- check4 weeks (100 mcg × 3/wk) ≈ 1 vial
- check6 weeks (100 mcg × 3/wk) ≈ 1 vial
- check8 weeks (150 mcg × 3/wk) ≈ 2 vials
Insulin Syringes (U‑100, 30‑ or 50‑unit preferred):
- checkPer week: 3 syringes
- check4 weeks: 12 syringes
- check6 weeks: 18 syringes
- check8 weeks: 24 syringes
Bacteriostatic Water (10 mL bottles): Use 2.0 mL per vial for reconstitution.
- check4–6 weeks (1 vial): 2 mL → 1 × 10 mL bottle
- check8 weeks (2 vials): 4 mL → 1 × 10 mL bottle
Alcohol Swabs: One for the vial stopper + one for the injection site each administration.
- checkPer week: 6 swabs (2/injection × 3 injections)
- check4 weeks: 24 swabs
- check6 weeks: 36 swabs
- check8 weeks: 48 swabs → recommend 1 × 100‑count box
Mechanism of Action (MOA)
Gonadorelin (gonadotropin-releasing hormone, GnRH; also known as luteinizing hormone-releasing hormone, LHRH) is a hypothalamic decapeptide with the sequence pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2 and a molecular weight of 1,182 Da. Endogenous GnRH is synthesized in the preoptic and arcuate nuclei of the hypothalamus by approximately fifteen hundred specialized GnRH neurons and is released into the hypothalamic-pituitary portal circulation in discrete pulses every 90 to 120 minutes during reproductive life. The pulsatile pattern is essential: continuous GnRH exposure desensitizes pituitary GnRH receptors and ultimately suppresses gonadotropin secretion, while intermittent pulses sustain receptor responsiveness and stimulate LH and FSH release [1]. At the anterior pituitary, GnRH binds the GnRH receptor on gonadotrope cells, a Gq-coupled GPCR that activates phospholipase C and downstream calcium and protein kinase C signaling. The result is biosynthesis and pulsatile release of luteinizing hormone and follicle-stimulating hormone. LH acts on Leydig cells in the testes to stimulate testosterone production and on theca cells in the ovary to drive androgen synthesis as the substrate for granulosa cell aromatization to estradiol. LH also triggers ovulation through its mid-cycle surge. FSH acts on Sertoli cells in the testes to support spermatogenesis and on granulosa cells in the ovary to drive follicular development and aromatase expression [2]. Clinically, gonadorelin has been used in three principal contexts. First, as a diagnostic agent: a single 0.1 mg subcutaneous or intravenous dose of gonadorelin produces a transient rise in serum LH and FSH that allows evaluation of pituitary gonadotrope function in suspected hypogonadotropic hypogonadism, delayed puberty, and after pituitary surgery or radiation. Second, as a treatment for hypothalamic amenorrhea and infertility due to hypothalamic GnRH deficiency: pulsatile subcutaneous gonadorelin delivered by a portable infusion pump at 5–20 mcg per pulse every 60–120 minutes restores natural cyclic gonadotropin secretion, follicular development, ovulation, and fertility with a much lower risk of ovarian hyperstimulation than exogenous gonadotropin therapy. Pulsatile gonadorelin therapy has also been used in men with congenital hypogonadotropic hypogonadism (Kallmann syndrome) to induce puberty, testicular growth, and spermatogenesis [3]. Third, in an off-label and increasingly popular contemporary application, low-dose subcutaneous gonadorelin (typically 50–200 mcg administered two to three times weekly, sometimes daily) is used as an adjunct to testosterone replacement therapy to preserve testicular volume, intratesticular testosterone production, and fertility in men on exogenous testosterone. This use has largely replaced the prior practice of administering hCG (chorionic gonadotropin) for the same purpose, particularly after manufacturing changes that restricted hCG availability and made gonadorelin more accessible through compounding pharmacies. The pharmacological rationale is somewhat distinct from pulsatile therapy: low-dose intermittent gonadorelin produces brief pituitary stimulation, with downstream LH pulses driving Leydig cell function and maintaining testicular size and intratesticular androgen levels during exogenous testosterone treatment [4]. The original branded gonadorelin products (Factrel injection, Wyeth; Lutrepulse pump system, Ferring) were withdrawn from the U.S. market, and no FDA-approved new drug application currently exists. Gonadorelin available in the United States is supplied by licensed compounding pharmacies and is regulated as a compounded drug rather than a finished pharmaceutical product. Diagnostic and pulsatile use continues in Europe and other jurisdictions where branded products remain available. Pharmacokinetic studies show rapid subcutaneous and intravenous absorption with an elimination half-life of two to ten minutes, reflecting rapid enzymatic degradation by endopeptidases [1].
Clinical Trial Efficacy Highlights
- starYen and colleagues' seminal work established the pulsatile nature of physiologic GnRH secretion and demonstrated that pulsatile subcutaneous gonadorelin (5–20 mcg every 90–120 minutes via portable pump) restores cyclic gonadotropin secretion, ovulation, and fertility in women with hypothalamic amenorrhea, with markedly lower risks of ovarian hyperstimulation than exogenous gonadotropin therapy [1].
- starDiagnostic gonadorelin stimulation testing (0.1 mg subcutaneously or intravenously with serial LH and FSH measurements) has been validated as a tool for evaluating pituitary gonadotrope function in suspected hypogonadotropic hypogonadism, delayed puberty, and after pituitary surgery or radiation [2].
- starPulsatile gonadorelin therapy in men with congenital hypogonadotropic hypogonadism (Kallmann syndrome) induces testicular growth, puberty, and spermatogenesis with response rates exceeding 70 percent for sperm production over six to twenty-four months, supporting its preferred use over exogenous gonadotropin therapy in men prioritizing fertility [3].
- starLiu and colleagues compared pulsatile gonadorelin with combined hCG and FSH therapy in men with hypogonadotropic hypogonadism and reported similar induction of spermatogenesis with potentially better testicular development and faster fertility outcomes with pulsatile gonadorelin in pituitary stalk interruption syndrome and Kallmann syndrome [4].
- starLow-dose subcutaneous gonadorelin (50–200 mcg 2–3 times weekly) used as an adjunct to testosterone replacement therapy in men preserves testicular volume and reduces the testicular atrophy and intratesticular testosterone suppression caused by exogenous testosterone, though formal published trials of this off-label use remain limited [3].
- starOriginal branded gonadorelin products (Factrel injection, Lutrepulse pump system) were withdrawn from the U.S. market for commercial reasons rather than safety concerns; gonadorelin remains in use through compounding pharmacies in the United States and through registered branded products in other countries [1].
- starSafety data accumulated over decades of clinical use indicate that gonadorelin is extremely well tolerated, with rare hypersensitivity reactions and uncommon mild headache, flushing, or local injection-site reactions; the favorable safety profile reflects the small dose required, the short plasma half-life, and the physiologic nature of the peptide [2].
Side Effects & Tolerability Profile
Clinical subjects transiently report mild side effects. Slowly escalating the titration dose represents the single most effective intervention to limit side effects.
- warningGonadorelin is exceptionally well tolerated; the most commonly reported adverse events are mild injection-site discomfort, transient erythema, and infrequent headache, flushing, or nausea.
- warningRare hypersensitivity reactions including urticaria, bronchospasm, and anaphylaxis have been reported with parenteral gonadorelin; patients with known peptide hypersensitivity should be evaluated before initiation.
- warningPulsatile pump therapy can cause local skin reactions at the subcutaneous catheter site, occasional infections, and rarely sterile abscesses; rotation of infusion sites mitigates these risks.
- warningContinuous (rather than pulsatile) GnRH exposure produces paradoxical pituitary desensitization and suppression of LH and FSH secretion, which is the basis for long-acting GnRH analog therapy in prostate cancer and endometriosis but is not the goal of gonadorelin therapy.
- warningTheoretical risks of low-dose adjunctive gonadorelin in TRT include incomplete preservation of fertility, variable testicular response, and the absence of formal long-term safety data in this off-label context.
- warningGonadorelin can transiently increase estrogen levels in men through downstream LH-driven testicular aromatization, potentially contributing to gynecomastia or water retention if doses are excessive or aromatase activity is high.
- warningUse during pregnancy is contraindicated, since GnRH-induced ovulation should occur before conception and gonadotropin stimulation during pregnancy can produce ovarian hyperstimulation.
Subcutaneous Injection Technique
Most research peptides require subcutaneous injection into fatty tissue. Never inject directly into a blood vessel or deep muscle tissue unless clinically detailed.
1. Site Selection
Common locations include the abdomen (2 inches from navel), outer upper arms, or thighs.
2. Sanitization
Thoroughly clean the selected site, stopper and vial top using 70% isopropyl alcohol prep swabs.
3. Angle & Push
Pinch the skin and insert the needle at a 45 to 90-degree angle. Depress plunger smoothly.
4. Site Rotation
Rotate injection sites continuously to avoid lipodystrophy or tissue scarring.
Frequently Asked Questions
What is the typical gonadorelin dosage?expand_more
Diagnostic stimulation uses a single 0.1 mg subcutaneous or intravenous dose. Pulsatile therapy for hypothalamic amenorrhea or hypogonadotropic hypogonadism uses 5–20 mcg every 90–120 minutes via portable pump. Off-label adjunctive TRT use is typically 50–200 mcg subcutaneously two to three times weekly.
How is gonadorelin administered?expand_more
Gonadorelin is administered subcutaneously or intravenously. Pulsatile therapy uses a portable subcutaneous infusion pump delivering microgram doses every 90–120 minutes. Off-label TRT-adjunctive use is by intermittent subcutaneous injection with an insulin syringe after reconstitution with bacteriostatic water.
Can gonadorelin be combined with other compounds?expand_more
Gonadorelin is commonly combined with exogenous testosterone in TRT protocols, with clomiphene or enclomiphene in post-cycle therapy, and historically with hCG in fertility regimens. Combination with other GnRH analogs or with continuous GnRH exposure is contraindicated due to receptor desensitization.
What are the side effects of gonadorelin?expand_more
Gonadorelin is very well tolerated. Common effects are mild injection-site reactions, occasional headache, flushing, or nausea. Hypersensitivity reactions are rare. Continuous (rather than pulsatile) administration suppresses rather than stimulates gonadotropin secretion.
Is gonadorelin FDA approved?expand_more
Gonadorelin was FDA approved historically as Factrel injection (Wyeth) for diagnostic use and as the Lutrepulse pulsatile pump system (Ferring) for hypothalamic amenorrhea, but both branded products have been withdrawn from the U.S. market. Compounded gonadorelin is currently available through licensed compounding pharmacies.
Academic References & Study Citations
Yen SS, Tsai CC, Naftolin F, Vandenberg G, Ajabor L. Pulsatile patterns of gonadotropin release in subjects with and without ovarian function. J Clin Endocrinol Metab. 1972;34(4):671-675. View Scientific Paper →
Conn PM, Crowley WF Jr. Gonadotropin-releasing hormone and its analogues. N Engl J Med. 1991;324(2):93-103. View Scientific Paper →
Pitteloud N, Hayes FJ, Dwyer A, Boepple PA, Lee H, Crowley WF Jr. Predictors of outcome of long-term GnRH therapy in men with idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 2002;87(9):4128-4136. View Scientific Paper →
Liu PY, Gebski VJ, Turner L, Conway AJ, Wishart SM, Handelsman DJ. Predicting pregnancy and spermatogenesis by survival analysis during gonadotrophin treatment of gonadotrophin-deficient infertile men. Hum Reprod. 2002;17(3):625-633. View Scientific Paper →
Mao JF, Xu HL, Duan J, et al. Comparison of efficacy of pulsatile gonadotropin-releasing hormone treatment in IHH patients. Asian J Androl. 2017;19(6):680-685. View Scientific Paper →
Boehm U, Bouloux PM, Dattani MT, et al. Expert consensus document: European Consensus Statement on congenital hypogonadotropic hypogonadism - pathogenesis, diagnosis and treatment. Nat Rev Endocrinol. 2015;11(9):547-564. View Scientific Paper →
Santoro N, Filicori M, Crowley WF Jr. Hypogonadotropic disorders in men and women: diagnosis and therapy with pulsatile gonadotropin-releasing hormone. Endocr Rev. 1986;7(1):11-23. View Scientific Paper →
Filicori M, Flamigni C, Dellai P, et al. Treatment of anovulation with pulsatile gonadotropin-releasing hormone: prognostic factors and clinical results in 600 cycles. J Clin Endocrinol Metab. 1994;79(4):1215-1220. View Scientific Paper →
Stamatiades GA, Kaiser UB. Gonadotropin regulation by pulsatile GnRH: signaling and gene expression. Mol Cell Endocrinol. 2018;463:131-141. View Scientific Paper →