Gonadorelin

Synthetic gonadotropin-releasing hormone used diagnostically and therapeutically for reproductive hormone assessment and fertility.

AStrongWell-Studied

Last updated October 5, 202622 citations

What is Gonadorelin?

Gonadorelin is a synthetic version of the naturally occurring gonadotropin-releasing hormone (GnRH), a decapeptide produced by the hypothalamus. When administered in pulsatile fashion, it stimulates LH and FSH release from the pituitary, supporting natural testosterone and estrogen production. It is used diagnostically to assess pituitary function and therapeutically for hypogonadism and fertility.

What Gonadorelin Is Investigated For

Gonadorelin is the synthetic form of GnRH and has been investigated across three main contexts: pituitary function testing (FDA-approved historically as Factrel), pulsatile therapy for hypothalamic amenorrhea (historically approved as Lutrepulse), and off-label TRT-adjunct use to preserve testicular function and fertility in men on exogenous testosterone. The strongest evidence is for diagnostic pituitary testing — decades of well-characterized use — and the historical approval data for pulsatile pump therapy in hypothalamic amenorrhea. The contemporary TRT-adjunct use is the most discussed but has the thinnest evidence base: no randomized controlled trials specifically evaluate gonadorelin versus hCG or placebo in men on TRT for fertility and testicular preservation, and protocols are empirical. The honest caveats are significant: both Factrel and Lutrepulse are discontinued in the US, leaving no FDA-approved commercial product; gonadorelin does not appear in any category of FDA's 503A nominated bulk-substance lists (May 14, 2026 update), so whether a pharmacy can compound it depends on section 503A's general rules for bulk ingredients (a USP–NF monograph, or being a component of an FDA-approved drug; gonadorelin was the active ingredient of Factrel and Lutrepulse) rather than on the category 1 interim policy; pulsatility is critical (continuous exposure paradoxically suppresses the axis via receptor desensitization, the same mechanism as leuprolide); and gonadorelin is named in WADA class S2.2.1 ('Testosterone-stimulating peptides in males'), so it is prohibited at all times for male athletes.

Maintaining natural testosterone during TRT alternatives

Moderate70%

Fertility preservation

Moderate70%

Pituitary function assessment

Strong90%

Alternative to HCG for testicular function

Emerging50%

History & Discovery

Gonadorelin is the synthetic form of gonadotropin-releasing hormone (GnRH), a 10-amino-acid hypothalamic peptide isolated and sequenced in the early 1970s by Andrew Schally's and Roger Guillemin's laboratories — work that contributed to their sharing the 1977 Nobel Prize in Physiology or Medicine. The peptide's sequence (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) is identical to endogenous human GnRH and is the physiologic trigger at the top of the hypothalamic-pituitary-gonadal axis. In the US, synthetic gonadorelin was marketed as Factrel (Ayerst/Wyeth) for pituitary function testing, and as Lutrepulse (Ferring) delivered via programmable pulsatile pump for primary hypothalamic amenorrhea and related infertility indications. Both products are now discontinued in the United States, though their FDA approval history remains on the record. International veterinary use of gonadorelin for reproductive synchronization in cattle and other livestock remains extensive — which accounts for much of the peptide's published randomized trial literature. The contemporary story is the rise of off-label gonadorelin use as a TRT adjunct: men on exogenous testosterone began using small, pulsatile subcutaneous doses to preserve endogenous testicular function and fertility, substituting for hCG, especially after hCG became a licensed biological product in March 2020 and could no longer be compounded. This use has been supplied mainly by US compounding pharmacies. Gonadorelin does not appear in any of FDA's 503A nomination categories (May 14, 2026 list), including category 2 (significant safety risks), where kisspeptin-10 has sat since September 2023; because it was the active ingredient of FDA-approved drugs, its compounding status turns on section 503A's general rules for bulk ingredients rather than on a category listing.

How It Works

Gonadorelin is the master reproductive hormone. Given in pulses (like the body naturally does), it tells the pituitary gland to produce LH and FSH, which then stimulate testosterone or estrogen production. It keeps the entire hormone chain working naturally.

Gonadorelin (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) binds the GnRH receptor (GnRHR) on pituitary gonadotrophs. Pulsatile activation (every 60-120 minutes) maintains receptor sensitivity and stimulates LH/FSH synthesis and secretion through Gq/PLC/IP3/DAG signaling. Pulse frequency determines LH vs FSH predominance. Continuous exposure causes receptor internalization and desensitization, paradoxically suppressing gonadotropins (the basis for GnRH agonist drugs like leuprolide).

Evidence Snapshot

Overall Confidence85%

Human Clinical Evidence

Extensive for diagnostic use. Moderate for therapeutic applications.

Animal / Preclinical

Comprehensive. GnRH biology is fundamental to reproductive endocrinology.

Mechanistic Rationale

Very strong. GnRH receptor signaling and HPG axis regulation are thoroughly characterized.

Research Gaps & Open Questions

What the current literature has not yet settled about Gonadorelin:

01Modern TRT-adjunct efficacy — despite widespread clinical use, randomized controlled trials specifically evaluating gonadorelin (vs. hCG, vs. placebo, vs. no adjunct) in men on TRT for fertility and testicular preservation are essentially absent. Dominikowski-adjacent narrative reviews (e.g., Front Reprod Health August 2026, PMID 42666625) synthesize the peptide-and-neuroendocrine strategies clinicians are being asked to counsel on, but do not substitute for controlled outcomes data.
02Optimal dosing for TRT adjunct — the 100–200 mcg SC two-to-three-times-weekly regimen is empirical; formal dose-ranging and pharmacokinetic-pharmacodynamic modeling in this specific population is missing.
03Long-term safety of chronic pulsatile gonadorelin — approved pump therapy was time-limited (months to achieve pregnancy); multi-year continuous TRT-adjunct exposure has no formal safety dataset.
04Comparative effectiveness vs. hCG — head-to-head trials comparing gonadorelin and hCG for testicular preservation, spermatogenesis, and symptomatic endpoints in TRT patients are lacking.
05Regulatory clarity — gonadorelin is not on FDA's 503A category lists, so its compounding status rests on section 503A's general rules for bulk ingredients rather than on an FDA evaluation of the substance itself, and later FDA action could still change access.
06Women's health applications beyond hypothalamic amenorrhea — contemporary use of pulsatile gonadorelin in broader infertility contexts is limited, and the discontinuation of Lutrepulse in the US has reduced research activity in this area. Contemporary case and observational reports continue to appear (Int J Womens Health 2026, PMID 42633415 — pregnancy achievement in idiopathic hypogonadotropic hypogonadism via pulse therapy; Gynecol Endocrinol 2026, PMID 42176250 — ovulation restoration in functional hypothalamic amenorrhea with PCOM stratification), but a modern controlled evidence base is not being built.
07Fresh mechanistic work continues to refine the pulsatility narrative — a 2026 Hormones (Athens) paper (PMID 42533270) shows GnRH pulse frequency is decoded by distinct Gα(s)- vs Gα(q/11)-mediated pathways in gonadotropes, but whether this translates into clinically actionable pulse-protocol optimization for humans remains an open question.
08Contemporary post-marketing safety surveillance — a 2026 FAERS analysis (Int J Mol Sci, PMID 42589332) evaluates adverse-event signals for predicted GnRHR agonists, but gonadorelin-specific real-world safety at compounded-pharmacy TRT-adjunct doses (100–300 mcg SC, 2–3x weekly, chronic) is not yet a separately characterized signal.

Forms & Administration

SC or IV injection. Diagnostic: 100mcg single dose. Therapeutic: 50-100mcg SC 2-3 times daily or via pulsatile pump. Timing mimics natural GnRH pulsatility. All injectable peptides should only be administered under the guidance of a qualified healthcare provider. Never self-administer without clinician oversight.

Dosing & Protocols

The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.

Typical Range

The historical FDA-approved diagnostic dose (Factrel) was 100 mcg as a single subcutaneous or intravenous injection for pituitary function testing. The approved Lutrepulse protocol used 5 mcg per pulse every 90 minutes delivered via programmable pump for hypothalamic amenorrhea. Off-label TRT-adjunct protocols are markedly different: typical doses are 100–300 mcg per subcutaneous injection, with some clinicians using up to 500 mcg. For TRT adjunct, the intent is to replicate pulsatile LH stimulation without causing receptor desensitization.

Frequency

Diagnostic use: single dose. Approved Lutrepulse therapy: every 90 minutes for weeks to months via pump. Off-label TRT adjunct: the most commonly described cadence is 100–200 mcg two to three times weekly, though daily small-dose protocols (100 mcg once daily) and every-other-day schedules are also used. Pulsatility is important mechanistically — continuous gonadorelin exposure causes GnRH receptor downregulation (the mechanism leveraged by leuprolide and other GnRH agonists used to suppress the axis).

Timing Considerations

No specific timing requirements: can be administered at any time of day, with or without food, and is not tied to exercise timing. Consistency matters more than the specific clock — dose at roughly the same time each day (or same day each week, for weekly protocols) to keep exposure steady.

Cycle Length

Diagnostic use is single-dose. TRT-adjunct use is typically continuous alongside exogenous testosterone, with periodic reassessment of testicular volume, semen analysis where fertility is the goal, and LH/FSH response. Long-term continuous use of pulsatile gonadorelin at TRT-adjunct doses has not been rigorously studied.

Protocol Notes

The critical pharmacologic feature of gonadorelin is that route-and-frequency determine whether it stimulates or suppresses the axis. Pulsatile dosing at physiologic frequency (every 90–120 minutes in the Lutrepulse protocol) mimics endogenous GnRH and maintains LH/FSH secretion. Continuous exposure — either through long-acting analogs like leuprolide or through steady-state infusion — desensitizes the receptor and profoundly suppresses gonadotropins. TRT-adjunct SC protocols (100–200 mcg a few times weekly) are an empirical compromise: they produce transient LH surges without continuous exposure, but the dosing is well above the physiologic pulse amplitude and the frequency is lower than physiologic. Reconstitution is straightforward — most compounded gonadorelin comes lyophilized and is reconstituted in bacteriostatic water, then injected subcutaneously with an insulin-gauge syringe. Storage stability post-reconstitution is limited (typically 1–2 weeks refrigerated), which affects practical dosing schedules. Gonadorelin is not on any of FDA's 503A category lists (May 14, 2026 update). Section 503A allows compounding with a bulk ingredient that has a USP–NF monograph or is a component of an FDA-approved drug, and gonadorelin was the active ingredient of the FDA-approved Factrel and Lutrepulse, so its compounding status turns on those general rules rather than on the category 1 interim policy. Compounded gonadorelin is not an FDA-approved product.

Gonadorelin's US FDA approval history covers diagnostic and pulsatile-pump indications that are no longer actively marketed. TRT-adjunct use is off-label. Any use should be under the supervision of a qualified clinician who can verify product sourcing and monitor response.

Timeline of Effects

Onset

LH and FSH rise within 15–30 minutes of a gonadorelin injection, with peak gonadotropin response typically at 30–60 minutes. Testosterone response downstream in men follows over hours, depending on baseline Leydig cell function and whether testicular volume has already been affected by exogenous testosterone suppression. For TRT-adjunct users aiming to preserve testicular size and fertility, observable changes in testicular volume and semen parameters unfold over weeks to months.

Peak Effect

Acute pituitary response peaks within the hour. For TRT-adjunct use, meaningful preservation or restoration of testicular volume and spermatogenesis is typically assessed at 3–6 months of consistent dosing — on the timescale of full spermatogenic cycles.

After Discontinuation

Acute effects resolve within hours — gonadorelin's plasma half-life is approximately 2–4 minutes, making it one of the shorter-lived peptides used clinically. For TRT users who stop gonadorelin while continuing exogenous testosterone, testicular atrophy and spermatogenesis suppression return to the trajectory dictated by the ongoing testosterone use. For those discontinuing both gonadorelin and exogenous testosterone, recovery of the HPG axis follows the general post-TRT trajectory without clear evidence that prior gonadorelin use meaningfully accelerates or impairs recovery.

Monitoring & Measurement

Bloodwork & Labs

•LH and FSH — the direct pituitary-output markers; the core endpoint for any gonadorelin protocol
•Total and free testosterone
•Estradiol via sensitive LC-MS/MS assay
•SHBG

Functional & Performance Tests

•Testicular volume via orchidometer — the simplest functional marker of preserved spermatogenesis during TRT-adjunct use
•Semen analysis — if fertility preservation is a goal

When to Test

Baseline, 4 weeks, and 12 weeks. For acute response confirmation, draw LH 30 minutes post-injection on a representative dose.

Interpretation & Notes

In TRT-adjunct use, the goal is maintaining endogenous testosterone production and testicular volume while on exogenous testosterone. Gonadorelin is pulsatile by design — continuous dosing downregulates GnRH receptors and paradoxically suppresses the axis, so injection frequency matters at least as much as dose. An acute post-injection LH rise of at least 2x baseline at the 30-minute mark confirms the pituitary is responding to a given protocol; failure to rise usually means either receptor downregulation from too-frequent dosing or a degraded batch. Reproductive-hormone panels are widely available direct-to-consumer; testicular ultrasound and orchidometer measurement usually require a clinician.

Common Questions

Why use gonadorelin instead of HCG?

Gonadorelin works upstream of HCG, stimulating the pituitary to produce LH naturally. This maintains the entire HPG axis rather than just mimicking LH. It's increasingly used because hCG has been regulated as a biological product since March 2020 and can no longer be compounded.

Can gonadorelin be compounded?

Gonadorelin is not on FDA's 503A category lists: the May 14, 2026 update places it in none of category 1 (under evaluation), category 2 (significant safety risks) or category 3. Section 503A lets a pharmacy compound with a bulk ingredient that has a USP–NF monograph or is a component of an FDA-approved drug; only ingredients that meet neither test need the bulks list and its interim categories. Gonadorelin was the active ingredient of the FDA-approved Factrel and Lutrepulse, so its status turns on those general rules, not on a category listing. Compounded gonadorelin is still not an FDA-approved product, and later FDA action could change access.

Why does gonadorelin have to be dosed in pulses?

Because GnRH receptors on pituitary gonadotrophs desensitize under continuous exposure. Pulsatile activation roughly every 60–120 minutes — mimicking endogenous GnRH — maintains receptor sensitivity and stimulates LH/FSH release. Continuous or steady-state exposure causes receptor internalization and downregulation, paradoxically suppressing gonadotropins. That suppression mechanism is exactly what long-acting GnRH analogs like leuprolide leverage to treat prostate cancer and endometriosis. Frequency, not just dose, determines whether gonadorelin stimulates or suppresses.

Can athletes use gonadorelin?

Not male athletes subject to WADA testing. Gonadorelin is named in WADA class S2.2.1, 'Testosterone-stimulating peptides in males', which covers GnRH (gonadorelin) and its agonist analogues; it is prohibited for men at all times, in and out of competition, on both the 2026 and 2027 Lists, and the same applies under USADA, UKAD, and equivalent national bodies. A man with a genuine medical need can apply for a Therapeutic Use Exemption.

Who Gonadorelin Is NOT For

Contraindications

•Known hypersensitivity to gonadorelin or to compounded-preparation excipients — documented anaphylactoid reactions have occurred, including from repeated diagnostic use.
•Hormone-sensitive malignancy — prostate cancer, certain breast cancers, and other hormone-responsive tumors where increased endogenous gonadotropin stimulation is contraindicated.
•Pregnancy — not indicated during pregnancy; while short half-life limits direct exposure, the hormonal effects are inappropriate in the pregnant state.
•Pituitary adenoma — gonadorelin stimulation testing in the presence of a known pituitary adenoma should be done by an endocrinologist with imaging and hormone-axis context, not empirically.
•Active or prior pituitary apoplexy — stimulation testing in this context carries specific risks that require specialist evaluation.
•Pediatric use outside of specific pediatric endocrinology indications (precocious puberty workup, cryptorchidism protocols) — empirical dosing in minors is not appropriate.

Drug & Supplement Interactions

Gonadorelin's short plasma half-life (minutes) limits sustained pharmacokinetic interactions, but its pharmacodynamic effects at the HPG axis create several meaningful interaction categories. The most important is with exogenous testosterone therapy — which is the primary off-label use case. Exogenous testosterone suppresses hypothalamic GnRH output; gonadorelin injection bypasses this by directly stimulating the pituitary. The interaction is the entire therapeutic rationale, but it means gonadorelin dosing should be calibrated against testosterone dose, frequency, and observed LH/FSH response, and managed by a clinician who understands both agents. Drugs that directly suppress GnRH or gonadotropin function — GnRH agonists and antagonists used in oncology and gynecology (leuprolide, goserelin, cetrorelix, degarelix), high-dose opioids, and high-dose glucocorticoids — oppose gonadorelin's intended effect and make dose interpretation unreliable. Anti-androgens, aromatase inhibitors, and selective estrogen receptor modulators interact downstream rather than at the pituitary and are generally compatible with gonadorelin therapy but should be managed by the prescribing clinician. Phenothiazines and dopamine antagonists can elevate prolactin and blunt gonadotropin response, complicating interpretation of diagnostic tests. Patients on any chronic medication should disclose gonadorelin use to their prescribing team.

Safety Profile

Safety Information

Common Side Effects

Injection site reactionsHeadacheNauseaFlushing

Cautions

• Must be administered in pulsatile fashion for stimulatory effect
• Continuous administration causes receptor desensitization (like leuprolide)
• Timing and frequency of dosing are critical

What We Don't Know

Well-characterized safety profile for diagnostic use. Long-term therapeutic use data is more limited.

Legal Status

United States

Gonadorelin was FDA-approved as Factrel (diagnostic) and Lutrepulse (pulsatile therapy for hypothalamic amenorrhea). Both products have been discontinued in the US, though the approval history remains on record. There is currently no FDA-approved commercial gonadorelin product in the US. Off-label TRT-adjunct use has relied on state-licensed 503A compounding pharmacies. Gonadorelin does not appear in any category (1, 2 or 3) of FDA's 503A nominated bulk-substance lists (May 14, 2026 update). Section 503A allows compounding with a bulk ingredient that has a USP–NF monograph or is a component of an FDA-approved drug; gonadorelin was the active ingredient of Factrel and Lutrepulse, so its compounding status turns on those general rules rather than on the category 1 interim policy. Research-chemical sales are not authorized for human use.

International

Gonadorelin and its veterinary counterparts are widely used internationally in livestock reproduction (cattle, sheep, horses), and the veterinary trial literature is extensive. Human prescribing varies by jurisdiction — some countries retain approved human-use products for diagnostic or fertility indications; others, like the US, have seen marketed products withdrawn over time. EMA and UK MHRA human-use availability is limited.

Sports & Competition

Gonadorelin is prohibited for male athletes at all times (in and out of competition) under WADA Prohibited List class S2.2.1, 'Testosterone-stimulating peptides in males', which names GnRH (gonadorelin) and its agonist analogues; the wording is the same in the 2026 and 2027 Lists, and all S2 substances are non-Specified. Male athletes subject to WADA code, USADA, UKAD, or equivalent bodies must treat gonadorelin as prohibited; a man with a genuine medical need can apply for a Therapeutic Use Exemption.

Regulatory status changes over time. Verify current local rules with a qualified professional.

Myths & Misconceptions

Myth

Gonadorelin is a currently FDA-approved drug.

Reality

Gonadorelin was FDA-approved as Factrel and Lutrepulse historically, but both products are discontinued. There is no currently marketed FDA-approved gonadorelin product in the US. Off-label TRT-adjunct use has relied on compounded product from 503A pharmacies. Gonadorelin is not on any FDA 503A category list, and compounded product is not the same as having an FDA-approved finished product on the market.

Myth

Gonadorelin and hCG do the same thing.

Reality

They act at different levels of the axis. hCG mimics LH and acts directly on Leydig cells to stimulate testosterone production, bypassing the pituitary. Gonadorelin stimulates the pituitary to release LH and FSH, preserving the entire HPG axis. The upstream mechanism is clinically meaningful when the goal is fertility preservation or natural LH pulsatility rather than just Leydig-cell stimulation.

Myth

Continuous gonadorelin dosing is fine and produces a stronger effect than pulsatile dosing.

Reality

The opposite is true. Continuous GnRH receptor exposure causes receptor internalization and desensitization — the mechanism leveraged by leuprolide and other GnRH agonists to suppress the HPG axis in prostate cancer and endometriosis. Gonadorelin only stimulates when delivered in pulses. Continuous infusion would suppress.

Myth

Gonadorelin prevents all TRT-related fertility loss.

Reality

Gonadorelin can help preserve testicular volume and spermatogenesis in many men on TRT, but it is not a guarantee. Individual response varies, semen parameters should be monitored when fertility is the goal, and men actively attempting conception during or shortly after TRT should work with a reproductive endocrinologist rather than rely on gonadorelin alone.

Myth

Gonadorelin is allowed for athletes because it's 'natural.'

Reality

Gonadorelin is named in WADA class S2.2.1, 'Testosterone-stimulating peptides in males', and is prohibited for male athletes at all times, in and out of competition. Male athletes subject to WADA testing should treat it as banned unless they hold a Therapeutic Use Exemption for a genuine medical need.

Published Research

22 studies

Emerging peptide and neuroendocrine strategies for TRT-induced reproductive suppression and functional male hypogonadism: a narrative review.

Front Reprod Health August 2026 narrative review directly on the TRT-adjunct use case that the page identifies as gonadorelin's largest evidence gap — the most current peer-reviewed synthesis of gonadorelin, hCG, kisspeptin, and related peptide strategies for preserving testicular function during exogenous testosterone therapy. Positions the empirical bodybuilding-community protocols against what the peer-reviewed literature can and cannot support.

ReviewPMID: 42666625

From Amenorrhea to Pregnancy: Comprehensive Management of GnRH Pulse Therapy Achieving Pregnancy in a Woman with Idiopathic Hypogonadotropic Hypogonadism.

Clinical StudyPMID: 42633415

Investigation of Adverse Events Associated with Predicted GnRHR Agonists Using the FAERS Database.

Systematic ReviewPMID: 42589332

GnRH pulse frequency is decoded by distinct Gα(s)- and Gα(q/11)-mediated signaling pathways in gonadotropes in vitro.

PreclinicalPMID: 42533270

Restoring ovulation in functional hypothalamic amenorrhea: impact of polycystic ovarian morphology on hormonal response to pulsatile GnRH.

Clinical StudyPMID: 42176250

Intramuscular and subcutaneous gonadotropin-releasing hormone agonist tests for central precocious puberty in girls: a randomized controlled trial

Randomized Controlled TrialPMID: 41986954

The efficacy and safety of rhGH treatment combined with letrozole/GnRHa in adolescent boys

Clinical TrialPMID: 39856629

Effect of a GnRH injection on kisspeptin levels in girls with suspected precocious puberty: a randomized-controlled pilot study

Clinical TrialPMID: 39847034

The safety of neoadjuvant hormonal treatment in infants with cryptorchidism

Clinical TrialPMID: 35691791

Effect of gonadorelin, lecirelin, and buserelin on LH surge, ovulation, and progesterone in cattle

Comparative StudyPMID: 25890780

Effects on normalized testicular atrophy index (TAIn) in cryptorchid infants treated with GnRHa pre and post-operative vs surgery alone: a prospective randomized trial and long-term follow-up on 62 cases

Randomized Controlled TrialPMID: 25106891

Comparison of gonadorelin products in lactating dairy cows: efficacy based on induction of ovulation of an accessory follicle and circulating luteinizing hormone profiles

Comparative StudyPMID: 19394072

Unchanged response to stimulation of pituitary hormone release after serial UV irradiation in men

Randomized Controlled TrialPMID: 9189734

Prospective case control study to determine the effect of lovastatin on serum testosterone and cortisol concentrations in hyperlipidemic nephrotic patients with chronic renal failure

Clinical TrialPMID: 8773342

Bioequivalency comparison between two gonadotropin-releasing hormone products

Randomized Controlled TrialPMID: 7771711

Luteinizing hormone-releasing hormone (LHRH) and its analogs for contraception in women: a review

Clinical TrialPMID: 6426857

[Value of short-term use of a gonadorelin analog in an in vitro fertilization program]

Randomized Controlled TrialPMID: 2949236

[Treatment of advanced prostatic cancer with a gonadorelin agonist, dTrp6 LHRH. 41 cases]

Clinical TrialPMID: 2934695

[Comparative clinico-therapeutic study of gonadorelin and chorionic gonadotropin in boys with undescended testes]

Clinical TrialPMID: 2885699

Efficacy and safety of intravenous pulsatile gonadotropin-releasing hormone: Lutrepulse for injection