Gonadorelin

Native GnRH decapeptide · pulsatile-stimulates / continuous-suppresses

Gonadorelin is a lab-made copy of GnRH (gonadotropin-releasing hormone), the natural 10-building-block peptide the brain's hypothalamus releases in short bursts to tell the pituitary gland to make LH and FSH — the two hormones that drive testosterone, sperm, estrogen, and ovulation. So it sits at the very top of the reproductive chain of command. The single most important thing to understand is that the same molecule does opposite things depending on how it is delivered: given in brief, on-then-off pulses (mimicking the natural hypothalamus) it stimulates the pituitary, but given as a constant steady level it overwhelms and shuts the pituitary down — the exact mechanism behind long-acting "chemical castration" drugs. Because it is destroyed within minutes in the blood, it was historically only practical as a hospital diagnostic test or via a programmable pulse pump (the old Lutrepulse fertility treatment). Today it lives mostly in compounded men's-health clinics, micro-dosed to try to keep the testes active during testosterone therapy — a role it inherited after compounded HCG became hard to get in the US in 2020. That men's-health use is widespread but extrapolated from mechanism, not proven by head-to-head trials against HCG.

The short version

Gonadorelin is a lab-made copy of GnRH (gonadotropin-releasing hormone) — a tiny 10-building-block peptide that your own hypothalamus (a control center deep in the brain) normally squirts out in short bursts. Each burst tells the pituitary (the master hormone gland just under the brain) to release two messenger hormones: LH and FSH. Those two then travel to the gonads (testes or ovaries) and switch on testosterone, sperm production, estrogen, and ovulation. So gonadorelin sits at the very top of the reproductive chain of command — it is the original "go" signal.

The crucial twist is timing. The brain naturally pulses GnRH — on for a few minutes, off for an hour or two, repeating. If you copy that pulsing rhythm with a pump, you get the natural effect: the pituitary keeps firing LH and FSH and the whole reproductive system runs. But if you flood the body with a constant steady level instead of pulses, the pituitary gets overwhelmed, pulls its receptors inside, and stops responding — the opposite of what you wanted. This is not a quirk; it is the foundational discovery (Knobil's lab, 1978) behind a whole class of "chemical castration" drugs that deliberately use continuous GnRH-type exposure to shut the gonads down in prostate cancer and endometriosis.

Because gonadorelin is destroyed within minutes of entering the blood, it was historically only practical as a hospital diagnostic test (one shot to see if the pituitary "wakes up") or via a programmable pump (the old Lutrepulse fertility treatment). Today it lives mostly in compounded men's-health and TRT clinics, where it is micro-dosed to try to keep the testes active during testosterone therapy — a role it inherited after compounded HCG became hard to get in the US in 2020. That men's-health use is widespread but extrapolated from mechanism, not proven by head-to-head trials.

Molecular identity

Specs

Molecular weight: 1182.3 g/mol (free base)
Molecular formula: C55H75N17O13
Monoisotopic mass: 1181.5730 Da
Water solubility: 1 mg/mL
Half-life: ~2–10 min (IV, plasma)

Sequence: pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2 (10 AA)PubChem CID 638793
Structure / class: Native GnRH / LHRH decapeptide (unmodified endogenous sequence)PubChem CID 638793
CAS / UNII: 33515-09-2 (free base) / 71447-49-9 (acetate) · 9O7312W37GPubChem CID 638793
Molecular target: GnRH receptor (pituitary gonadotrophs) — pulsatile stimulates, continuous suppressesPubChem CID 638793
Brand / approval: Historically FDA-approved as Factrel (diagnostic) & Lutrepulse (pulsatile fertility); both commercially discontinued in the US (manufacturer withdrawal, not safety)Widely cited (not registry-verified)
Anti-doping status: Prohibited in males at all times (WADA S2.2); not prohibited in femalesWADA 2026

Plain English

Mechanism

Gonadorelin binds the GnRH receptor — a G-protein-coupled receptor (a cell-surface switch) on the pituitary's gonadotroph cells. Switching it on triggers the synthesis and pulsed release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH drives testosterone from the testes' Leydig cells (men) and the ovulatory surge (women); FSH drives sperm production (men) and follicle development (women). Gonadorelin IS native GnRH — the exact natural decapeptide, not a modified analogue — which is what gives it its defining minutes-long half-life.

The centerpiece is pulsatile versus continuous. Pulsatile delivery — a pulse roughly every 60–120 minutes — maintains the receptor and sustains LH/FSH; this is the physiologic mode and the basis of pulsatile-pump fertility therapy and the diagnostic stimulation test. Continuous delivery — a steady, non-pulsed level — causes the receptor to internalize and uncouple, so after an initial "flare" rise LH and FSH progressively fall: paradoxical suppression. That is precisely why long-acting GnRH agonists (leuprolide, goserelin, triptorelin), which act like continuous exposure, suppress the gonads, and it is the mechanistic ceiling on how much or how often gonadorelin can be dosed before it backfires.

The defining demonstration is animal: Belchetz, Plant, Nakai, Keogh and Knobil (1978) lesioned the hypothalamus in rhesus monkeys, then showed that pulsatile GnRH restored LH/FSH while a continuous infusion of the same total dose caused an initial rise then progressive suppression — reversible on returning to pulses. The human corroboration is therapeutic: pulsatile-pump ovulation induction works in hypothalamic amenorrhea precisely because it respects the pulse requirement, and continuous-acting GnRH agonists clinically suppress the human gonadal axis.

Sources:PMID 100883 PMID 36378460

Why people reach for it

Potential benefits

Gonadorelin is native GnRH — the original "go" signal at the top of the reproductive axis — and people reach for it to keep their own pituitary engaged. Here's the appeal, with the pulsatile catch kept in view.

Keep the testes switched on during TRT — Its main community draw. By signaling the pituitary to release LH and FSH, gonadorelin is micro-dosed alongside testosterone to keep the testes active — the role it inherited as an HCG substitute, though no head-to-head trial proves it equals HCG.
Stimulate your own LH and FSH, not replace them — Unlike a direct LH-mimic, gonadorelin works one rung up — on the pituitary — so people reach for it when keeping the body's own gonadotropin output running is the goal.
A proven fertility tool when delivered in pulses — Via a pulsatile pump it induces ovulation in hypothalamic amenorrhea with high live-birth rates and unusually low multiple-pregnancy risk — a genuinely evidence-backed use, distinct from the community TRT-adjunct convention.
The pituitary rung of an HPG-axis stack — It sits between Kisspeptin-10 (the hypothalamic trigger above it) and hCG (the direct gonadal signal below it), so it pairs logically for people building a full-axis approach.
The honest catch — pulsatile-or-it-backfires — The same molecule suppresses the axis if given continuously (the mechanism behind "chemical castration" drugs), so the benefit depends entirely on respecting the pulse interval; dose too often and it does the opposite of what's intended. It's also prohibited in male athletes (WADA S2.2).

Sources:PMID 100883 PMID 2122733 PMID 36378460 PMID 26365959

What people reach for Gonadorelin for, drawn from what the research reports and how it's used — the pulsatile fertility and diagnostic uses are evidence-backed; the men's TRT-adjunct use is community convention, not proven equivalent to HCG.

Implied timing

Best time to dose

Implied best time

Morning (or per protocol)

For TRT-adjunct micro-dosing, most people inject in the morning (roughly aligning with natural LH pulsatility) — but the interval between doses matters far more than the hour.

The interval is everything: gonadorelin stimulates only when pulsed and suppresses when given too frequently, so spacing doses ~12 hours apart (e.g. 8 AM and 8 PM for a BID schedule) to let the pituitary receptor reset is the real timing lever — far more than the clock time.
Morning aligns roughly with the body's own higher morning LH pulsatility, which is why it's the common anchor for the first daily dose — but it's a sensible default, not a studied requirement.
Its ultrashort half-life (~2–10 min) is exactly what forces pulsatile delivery: the drug clears fast enough to avoid the steady-level buildup that would desensitize the receptor, so each dose is a brief, discrete pulse rather than a sustained level.
"Per protocol" carries real weight here — pulsatile-pump fertility use and the diagnostic stim test follow their own clinical schedules, and the community TRT-adjunct pattern (BID or 3×/week) is about pulse spacing, not a fixed time of day.

No study sets an ideal time of day for gonadorelin — this is reasoned from its pulsatile mechanism and natural LH rhythm. As a rule of thumb most peptide dosing lands in the midday-to-evening window; gonadorelin leans morning for the first pulse, but the dose interval (never continuous) is what actually matters, and clinical uses follow their own protocols.

Sources:PMID 100883

How to run it

Dosing & protocol

Gonadorelin is injected subcutaneously — the route used in community micro-dosing and by the on-page calculator. Its most critical constraint is not the dose amount but the interval: too frequent means the receptor desensitizes and the pituitary shuts down instead of firing. Every number below is community-and-practitioner convention for the men's-TRT-adjunct use; the pulsatile ovulation-induction and diagnostic uses are evidence-backed clinical medicine handled in the research dosing table.

Pulsatile vs continuous is real pharmacology — not a quibble. Dose too often and gonadorelin suppresses rather than stimulates. Men's TRT-adjunct use is community convention: mechanism-plausible, but no published trial has proven it equivalent to HCG for maintaining intratesticular testosterone or sperm. WADA S2.2 prohibits gonadorelin in male athletes at all times.

Tiered dose ranges — men's TRT-adjunct (SubQ)

Community convention centers on doses small enough to mimic a physiologic pulse without oversaturating the receptor.

Starting / conservative:: 100 mcg twice daily (BID) — injected ~12 hours apart to approximate two distinct pituitary pulses per day. The calculator's default; chosen to stay comfortably within the pulsatile window.
Standard community range:: 100–200 mcg twice daily. Most TRT clinics and community protocols cluster here. Some extend to three times per week (TIW) rather than BID — accepting fewer pulses per week in exchange for even more distance from continuous exposure.
Diagnostic bolus (clinical, not community):: 100 µg IV once — the validated GnRH-stimulation test dose. Not a TRT protocol; listed for reference so the numbers are not confused.

Subcutaneous administration

SubQ injection into fat — same as all community research-peptide use.

Injection site:: Abdomen (a couple of inches from the navel), love-handle area, or outer thigh. Rotate sites between doses — using one spot repeatedly causes local irritation and fatty lumps (lipohypertrophy).
Measuring the dose:: Drawn on a U-100 insulin syringe from the reconstituted vial. At the standard 10 mg vial + 2 mL bacteriostatic water mix (5,000 mcg/mL): 100 mcg = 2 IU · 200 mcg = 4 IU. The on-page calculator converts any vial size live.
Timing and interval:: The interval is everything. BID dosing spaces injections ~12 hours apart (e.g. 8 AM and 8 PM) to give the pituitary receptor time to reset. Morning injection also roughly aligns with the body's natural LH pulsatility. Avoid injecting more than twice daily — narrowing the gap moves toward continuous exposure and risks paradoxical suppression.
Food window:: SubQ gonadorelin is not meaningfully affected by food. Inject at a consistent time relative to your TRT or testosterone dose.

Cycle & washout

TRT-adjunct use is typically run continuously alongside testosterone therapy for its duration, rather than on a fixed 4-8-week peptide cycle.

On-TRT use:: Gonadorelin is started alongside or shortly after initiating testosterone therapy and run for as long as preserving testicular function is the goal. There is no standard washout in this context — the reason to stop is typically switching to HCG, coming off TRT, or transitioning to a fertility protocol.
Cycle re-check:: Assess LH/FSH response and testicular volume at 8–12 weeks. Because gonadorelin depends on a responsive pituitary, heavy testosterone-induced LH suppression can blunt the effect; some protocols add hCG or adjust testosterone dose if response is insufficient.
Coming off TRT (PCT context):: Gonadorelin is occasionally used in early post-cycle recovery to stimulate the pituitary while the testosterone feedback clears. In this context it is run for 4–6 weeks, often alongside a SERM (clomiphene or enclomiphene), with the same BID dosing.

Reconstitution at a glance

The on-page calculator does this live; quick reference for the standard 10 mg vial:

Mixing:: 10 mg vial + 2 mL bacteriostatic water = 5,000 mcg per mL. On a 100-unit (1 mL) insulin syringe: 100 mcg = 2 IU · 150 mcg = 3 IU · 200 mcg = 4 IU · 250 mcg = 5 IU.
Why 2 mL:: The 10 mg vial is a high-concentration vial even at 2 mL — each IU is 50 mcg, so small doses land on measurable syringe units. Adding more water is fine for a lower concentration if you prefer more IU per dose.

Sources:PMID 100883 PMID 2122733 PMID 36378460

Substrate the signal needs

Nutritional cofactor precision

Gonadorelin presses the trigger — it tells the pituitary to signal the gonads. But the axis delivers only if it is fuelled. The HPG chain (hypothalamus → pituitary → gonads) is energy-gated and substrate-dependent: no fuel means no GnRH signal upstream; no steroid substrate means no testosterone downstream even when LH/FSH are firing. These cofactors address both constraints, derived from HPG-axis physiology, not a gonadorelin-specific cofactor study.

Reasoned from HPG-axis physiology + steroidogenesis nutrition — not gonadorelin cofactor trials. Supplement doses are community convention. Correcting a deficiency removes a brake; none of these are testosterone boosters in someone already replete.

Energy adequacy + body fat (axis permissive condition)

The HPG axis is energy-gated — it reads the body as safe to reproduce only when fuel is sufficient. This is the primary brake gonadorelin cannot override.

Mechanism:: Very low body fat (men under ~8–10%), aggressive caloric restriction, or heavy endurance training suppresses hypothalamic GnRH pulsatility directly — the same functional hypothalamic amenorrhea that pulsatile gonadorelin is used to treat. If the body is energy-starved, the downstream signal has no permissive context to land in.
Protocol integration:: Maintain body fat above the reproductive-suppression threshold. Avoid aggressive caloric deficits (>500 kcal/day sustained) during a gonadorelin protocol. Adequate dietary fat — including cholesterol, the literal precursor to every sex steroid — matters; extreme low-fat eating removes the steroidogenesis starting material.

Cortisol + stress reduction (axis brake)

Chronic cortisol and elevated prolactin both suppress GnRH and LH signaling directly — two brakes that sit upstream of the pituitary signal gonadorelin is trying to reinforce.

Mechanism:: Cortisol (the stress hormone) inhibits GnRH at the hypothalamus and blunts LH at the pituitary. Prolactin elevation (from chronic stress, poor sleep, or dopamine-suppressing drugs) similarly gates GnRH release. Both are 'keep-the-brake-on' signals; gonadorelin presses the accelerator into that brake.
Protocol integration:: 7–9 hours of sleep is the single highest-impact lever — sleep is when LH pulses are most frequent and GH/testosterone peak. Stress management (avoiding prolonged cortisol elevation) and avoiding prolactin-raising drugs (antipsychotics, some antiemetics, SSRIs at high dose) are the actionable targets. Adaptogens such as ashwagandha (KSM-66, 300–600 mg/day) have cortisol-modulating evidence and are commonly stacked here.

Zinc + Vitamin D + Magnesium (steroidogenesis substrate)

LH/FSH arrive at the testes and tell the Leydig cells to make testosterone from cholesterol. This chain requires cofactors — deficiency in any blunts the output even when the upstream signal is perfect.

Zinc:: 15–30 mg/day zinc picolinate or bisglycinate. Zinc is a direct cofactor in testosterone synthesis (17β-HSD enzyme) and a natural brake on aromatase (the enzyme that converts testosterone to estrogen). Frank zinc deficiency consistently associates with lower testosterone; repletion restores it. Pair with 1–2 mg copper bisglycinate if running >15 mg zinc daily to prevent copper depletion.
Vitamin D:: Target serum 25-OH vitamin D of 50–80 ng/mL. Vitamin D receptor is expressed in Leydig cells; deficiency is associated with lower testosterone independent of LH/FSH levels. Dose to bloodwork — typically 2,000–5,000 IU/day D3 + K2 (100 mcg MK-7) to direct calcium appropriately.
Magnesium:: 300–400 mg/day elemental magnesium glycinate or threonate (before bed). Magnesium is a cofactor for steroid hydroxylase enzymes and reduces SHBG binding, making more testosterone biologically active. Sleep improvement from magnesium also compounds with the cortisol benefit.

Boron (SHBG reducer)

A trace mineral that lowers sex hormone-binding globulin (SHBG), releasing more free testosterone from the same total pool — relevant when LH/FSH are driving production but free-T is still low.

Mechanism:: Boron supplementation (3–10 mg/day) consistently lowers SHBG in clinical studies. Lower SHBG means a higher proportion of total testosterone is free and bioavailable, amplifying the effect of gonadorelin-stimulated testosterone production without raising total testosterone.
Protocol integration:: 3–6 mg boron glycinate daily with food. The effect is modest but additive with the steroidogenesis substrate stack above.

Combinations + timing

Stacking notes + timing windows

Gonadorelin sits at the pituitary rung of the HPG axis: hypothalamus (kisspeptin) → pituitary (gonadorelin) → gonad (HCG mimics LH directly). The most meaningful pairings work at adjacent rungs on the same ladder — different positions, not the same lever twice. Stacking two pituitary stimulators would be redundant.

HPG-axis logic plus clinical and community convention — not head-to-head trials of these combinations. Gonadorelin's contribution to any stack depends entirely on a pituitary that is not already maximally suppressed by testosterone feedback, and on staying in the pulsatile window.

Gonadorelin + Kisspeptin-10 (one rung up)

Kisspeptin is the upstream trigger that tells the hypothalamus to release GnRH; gonadorelin IS the GnRH signal. Together they run the top two rungs of the axis.

Why it works:: Kisspeptin-10 acts at the hypothalamus, stimulating endogenous GnRH release via the kisspeptin receptor (Kiss1R). Gonadorelin then provides exogenous GnRH at the pituitary directly. The pairing is additive along the physiologic cascade rather than redundant — kisspeptin amplifies the upstream drive, gonadorelin ensures the pituitary rung is hit even if endogenous GnRH is suppressed. Different rungs on one axis, not the same lever.
The protocol:: Gonadorelin 100 mcg SubQ BID (standard TRT-adjunct schedule) + kisspeptin-10 on its own community schedule (commonly 100–200 µg SubQ BID, mirroring gonadorelin timing). The combination is used in men's fertility contexts and post-cycle recovery more than in stable TRT maintenance.
Outcome:: Reached for in HPTA restart protocols, hypogonadotropic hypogonadism with intact pituitary, and fertility optimization. Note: both are convention-based; the combination has no head-to-head trial.

Gonadorelin + HCG (one rung down — typically alternatives, not co-stack)

HCG mimics LH and acts directly on the testis. Gonadorelin acts on the pituitary one level higher. These are the same job from adjacent rungs — understand the distinction before combining.

Why they differ:: HCG is a direct LH analog — it hits the Leydig cells of the testes and stimulates testosterone and intratesticular testosterone regardless of pituitary status. Gonadorelin relies on a responsive pituitary to generate LH. On TRT, where testosterone feedback suppresses the pituitary, gonadorelin's effect is attenuated; HCG bypasses that suppression entirely. Most clinics treat them as substitutes for the same goal, not a complementary stack.
When combining makes sense:: Some fertility-focused protocols layer both: gonadorelin 100 mcg BID to maintain pituitary signaling + HCG 500–1,000 IU 2× weekly to provide direct gonadal stimulation, particularly when the goal is sperm production alongside testosterone maintenance. This is specialist territory — inform your prescriber.
Outcome:: The combination is used in fertility-restoration protocols in men on long-term TRT who want to maintain spermatogenesis. For simple testicular-size maintenance on TRT, most protocols pick one or the other, not both.

Gonadorelin + clomiphene or enclomiphene (same-goal, different route)

SERMs raise endogenous LH/FSH by blocking estrogen feedback at the hypothalamus and pituitary — a different mechanism chasing the same output as gonadorelin.

Why it works:: Clomiphene and enclomiphene (selective estrogen receptor modulators) remove estrogen's negative feedback on the hypothalamus and pituitary, letting the body's own GnRH and gonadotropin levels rise. Gonadorelin adds exogenous GnRH on top of that. The combination is most logical in post-cycle recovery (PCT), where the goal is rapid HPG-axis restart — hitting the feedback brake (SERM) + the pituitary signal (gonadorelin) simultaneously.
The protocol:: PCT context: gonadorelin 100 mcg SubQ BID for 4–6 weeks, alongside enclomiphene 12.5–25 mg daily or clomiphene 25–50 mg daily. Timing: start gonadorelin when the testosterone ester clears (ester-length dependent), with SERM beginning at the same point.
Outcome:: Reached for in post-anabolic-steroid-cycle recovery (PCT) to restart the HPG axis. Honesty axis: WADA S2.2 prohibits gonadorelin in males — a post-cycle combination is still a prohibited-substance context for competitive athletes.

Reconstitution math

Reconstitution calculator

Calculated for a 1 mL U-100 insulin syringe (100 units/mL).

Peptide per vial

BAC water added

Desired dose

Units per dose

Draw to this mark on a U-100 syringe

Volume per dose: 0.02 mL
Doses per vial: 100
Concentration: 5 mg/mL

One vial lasts

Daily: 100 days
Every other day: 200 days
5×/week: 140 days

Research use only. Not for human consumption. Outputs are reference values based on research literature — verify all measurements independently.

From the studies

Side effects from research

Gonadorelin is generally mild and short-lived in its effects. The most common are brief flushing or hot flushes, headache, and nausea (which often resolves within 30–60 minutes), with occasional abdominal or GI discomfort. Injection-site reactions — local tenderness, soreness, mild bruising — are more common with the SC pump or a long-term indwelling cannula, and rare thrombophlebitis can occur with an indwelling IV line.

Rarer but more serious: hypersensitivity, including allergic or anaphylactoid reactions, has been reported (more often with repeated administration), and occasional antibody formation can occur with long pump courses. Ovarian hyperstimulation syndrome is uncommon at physiologic pulsatile dosing — a key advantage over injectable gonadotropins — but is still possible, especially when combined with other ovulation agents.

Label-context contraindications include hypersensitivity to gonadorelin, pregnancy, conditions worsened by gonadotropin stimulation (such as hormone-dependent tumors), and pre-existing ovarian enlargement or cysts not due to PCOS; caution applies with pituitary tumors or hyperprolactinemia.

Sources:PMID 2122733

As reported in literature

Research dosing ranges

These are the doses studied in the published literature, shown separately so the trial evidence is never mistaken for a recommended regimen. Gonadorelin's strongest evidence is for two roles — pulsatile ovulation induction and the diagnostic stim test — both human. The foundational pulsatile-vs-continuous mechanism is animal. Notably, no controlled trial of gonadorelin as an HCG substitute in TRT men exists, so that use has no row.

Dose	Route	Model	Outcome	Sources:
1 µg/min × 6 min hourly (pulsatile) vs same total continuous	IV	Animal — rhesus monkeys, hypothalamic-lesioned	Pulsatile restored and maintained LH/FSH; continuous → initial rise then progressive suppression; reversible on return to pulsatile (the founding demonstration)	PMID 100883
5 µg/90 min (range 1–20)	IV or SC pump	Human — women, functional hypothalamic amenorrhea (multi-center)	~68% ovulation at 5 µg/90 min IV; 91–96% ovulation pooled across regimens; favorable safety	PMID 2122733
Pulsatile pump protocol	SC/IV pump	Human — n=66 FHA patients, 212 cycles (25-year cohort)	Ovulation ~96%/cycle; live-birth 65.9% per treatment; single-follicle 75%; low multiple-gestation	PMID 36378460
100 µg (60 µg/m² peds) bolus	IV	Human — delayed-puberty males & females (diagnostic)	A single gonadorelin stim test was largely sufficient to distinguish hypogonadotropic hypogonadism from constitutional delay in males	PMID 26365959

Quick answers

Frequently asked

Gonadorelin vs HCG — what's the difference?

HCG mimics LH and acts directly on the testis or ovary, working even when the pituitary is suppressed. Gonadorelin acts one level higher — on the pituitary — telling it to make its own LH and FSH. So gonadorelin can in theory support both testosterone and sperm signaling, but only if the pituitary is responsive and only if dosed in pulses. On TRT, where feedback suppresses the pituitary, its effect is less certain, and no head-to-head trial proves the two are equivalent.

Why does continuous use suppress instead of stimulate?

Constant receptor occupancy makes pituitary cells pull their GnRH receptors inside and stop responding (desensitization). After a brief initial "flare," LH and FSH fall. Pulses — on then off — let the receptors reset between hits, which is why only pulsatile dosing stimulates. This is the exact mechanism that makes long-acting GnRH agonists chemically castrate.

Is gonadorelin the same as leuprolide or triptorelin?

No. Gonadorelin is the native, unmodified GnRH decapeptide with a minutes-long half-life. Leuprolide, triptorelin, goserelin and the like are modified agonists engineered to last long — and that long, continuous action is precisely what makes them suppressive rather than stimulatory.

Why does it need a pump?

Because it is destroyed in 2–10 minutes. To reproduce the body's natural rhythm you must re-dose every ~90 minutes, which historically meant a programmable pump (Lutrepulse). The short half-life isn't a flaw — it is what keeps dosing in the safe, stimulating, non-desensitizing window.

Does gonadorelin restore fertility?

In hypothalamic causes — where the pituitary is fine but the GnRH signal is missing — pulsatile gonadorelin can induce ovulation with high live-birth rates and unusually low multiple-pregnancy risk. It does nothing for pituitary failure (the pituitary can't respond) — which is actually how the diagnostic test tells the two apart.

Can gonadorelin replace HCG on TRT?

It is widely used that way in compounding clinics, especially since US compounded HCG access tightened in 2020 — but this is convention, not proven. There is no published trial showing gonadorelin maintains intratesticular testosterone or sperm as well as HCG in men on testosterone.

Is it banned in sport?

Yes — in males. Gonadorelin and its agonist analogues are on the 2026 WADA Prohibited List under S2.2 and are prohibited for male athletes at all times, as testosterone-stimulating agents. They are not prohibited in females. Athletes should verify current status via GlobalDRO for their sport and date.

Primary sources

References

PubChem CID 638793PubChem CID 638793 (Gonadorelin)
PMID 100883Belchetz et al., Science 1978 (pulsatile vs continuous GnRH, rhesus monkeys)
PMID 2122733Santoro, Am J Obstet Gynecol 1990 (IV pulsatile GnRH / Lutrepulse efficacy & safety)
PMID 36378460Quaas et al., J Assist Reprod Genet 2022 (pulsatile GnRH in FHA, 25-year cohort)
PMID 26365959Sun et al., Chin Med J 2015 (GnRH stimulation test in delayed puberty)
WADA 2026WADA 2026 Prohibited List, S2.2 — GnRH/gonadorelin & agonists prohibited in males

Research use only · Not medical advice · Updated 2026-06-01