Gonadorelin
Also known as: GnRH, LHRH, Factrel, Lutrepulse, Gonadotropin-Releasing Hormone
Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
Gonadorelin is synthetic GnRH that stimulates the pituitary to release LH and FSH. Per DrugBank and StatPearls, it works one level upstream of the testes, restoring/maintaining the body's OWN hormonal signaling rather than supplying an exogenous anabolic hormone or building muscle. Used for PCT and on-cycle testicular maintenance, functionally similar to kisspeptin (upstream) and HCG (downstream). Rated 2, in line with other pure axis-support/ancillary compounds that do not move the needle on muscular potential. Any benefit is confined to preserving natural testicular/fertility function, not enhancement beyond natural.
Overview
A synthetic decapeptide identical to endogenous GnRH that stimulates the pituitary to release LH and FSH. Unlike HCG (which directly mimics LH at testicular level), gonadorelin works upstream by stimulating natural pituitary signaling. Very short half-life (2-40 min) is a major limitation. May help maintain testicular function during TRT but HCG is superior for fertility preservation. Often used as HCG alternative when HCG is unavailable.
Important Warnings
- •NEVER use for more than 3 consecutive days - causes pituitary desensitization
- •Very short half-life (2-40 min) limits effectiveness vs HCG (36 hrs)
- •NOT reliable for fertility preservation on TRT - HCG is superior
- •Continuous exposure SUPPRESSES LH/FSH (opposite of intended effect)
- •Human formulations discontinued in USA - must use compounding pharmacies
- •Not FDA-approved for bodybuilding or PCT
- •Research peptide quality is unverified
- •Less effective when HPG axis is severely suppressed
- •Clinical applications require pulsatile pump for effectiveness
Purpose & Use Cases
Post-Cycle Therapy
Stimulates natural LH/FSH release to restart endogenous testosterone production after AAS use. Limited to 1-3 day protocols to avoid receptor desensitization.
On-Cycle Testicular Maintenance
May reduce testicular shrinkage during TRT/AAS use - clinic/community sources commonly cite maintaining roughly 50-60% of testicular function, though this figure is not from a peer-reviewed clinical trial. Less effective than HCG but maintains natural HPG axis signaling.
HCG Alternative
Used when HCG is unavailable or cost-prohibitive. Lower cost ($15-50/month vs $70-100 for HCG). Does not cause LH receptor desensitization.
Fertility (Clinical Use)
Pulsatile pump therapy achieves 90% spermatogenesis rate in hypogonadotropic hypogonadism with median onset of 6 months.
Benefits
- Stimulates NATURAL LH/FSH release (upstream mechanism)
- Does not cause LH receptor desensitization like HCG
- Commonly cited (community/clinic sources, not a peer-reviewed trial) to maintain ~50-60% testicular function on TRT
- Lower cost than HCG ($15-50/month)
- Available from compounding pharmacies when HCG restricted
- Preserves natural HPG axis signaling pathway
- Initial flare: LH increases up to 10-fold, testosterone to 140-200% baseline
- Stimulates FSH as well as LH (HCG primarily mimics LH only)
Good to Know
It IS GnRH, the pituitary's "go" signal
Gonadorelin is synthetic gonadotropin-releasing hormone. It tells your own PITUITARY to release LH and FSH, so it works one level ABOVE HCG: HCG mimics LH directly at the testes, whereas gonadorelin drives your natural LH/FSH from the top. That makes it part of the "upstream restart" family alongside kisspeptin and SERMs.
It must be PULSED, continuous use backfires
The pituitary only responds to gonadorelin in pulses. Steady, continuous exposure DOWNREGULATES the GnRH receptor and paradoxically SHUTS DOWN LH/FSH. This is precisely how GnRH-agonist drugs (Lupron) are used to chemically suppress hormones for prostate cancer/endometriosis. Never run gonadorelin continuously or for more than a few consecutive days.
The short half-life is the practical catch
At 2-40 minutes, its effect is brief. A real clinical restart uses a pulsatile pump delivering a dose roughly every 90 minutes. Impractical for most users, which is why HCG is usually the more reliable choice for on-cycle testicular maintenance and fertility. Gonadorelin is mostly used as a lower-cost HCG stand-in.
Needs a functional pituitary to work
Because it acts by stimulating the pituitary, gonadorelin is less effective when the axis is severely suppressed and will not help if the pituitary itself is impaired. The same limitation that applies to kisspeptin and SERMs but not to HCG/HMG, which act directly at the testes.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 100 – 200 mcg/week |
| Intermediate | 200 – 300 mcg/week |
| Advanced | 300 – 600 mcg/week |
DO NOT exceed ~200mcg per injection or dose on more than 3 consecutive days - continuous/daily use downregulates the pituitary GnRH receptor and paradoxically SUPPRESSES LH/FSH. Very short half-life (2-40 min) requires frequent dosing for any sustained effect. Clinical pulsatile-pump protocols use ~5-20mcg every 90-120 minutes (impractical outside a fertility clinic). Community on-cycle/TRT protocols cluster around 100mcg SC 2-3x weekly (~200-300mcg/week - dosing not FDA-established, community-derived); short PCT-style restart bursts use a single 100-200mcg dose (or brief daily dosing) for at most 3 consecutive days, then stop or transition to SERMs/HCG.
Very short half-life means the effect is brief and frequent (ideally pulsatile) dosing is required for any sustained effect, a major practical limitation versus HCG.
Side Effects
Injection Site Reactions
commonRedness, itching, swelling, irritation at injection site.
Rotate injection sites.
Stomach Upset
uncommonMild GI discomfort.
Usually transient.
Headache / Flushing / Dizziness
uncommonListed in FDA labeling for Factrel (gonadorelin HCl): headache, flushing, lightheadedness/dizziness after dosing.
Usually mild and transient.
Mood Changes
uncommonAgitation or depression from hormonal fluctuations.
Monitor mood. Usually related to hormone swings.
Breast Tenderness
uncommonRelated to temporary estrogen increases from testosterone flare.
Usually transient. Consider AI if persistent.
Pituitary Desensitization
commonContinuous or prolonged use causes pituitary GnRH receptor downregulation, paradoxically SUPPRESSING LH/FSH.
NEVER use >3 consecutive days. Use intermittently. Pulsatile administration preferred.
Hypersensitivity Reaction
rareFDA labeling for Factrel notes rare hypersensitivity reactions (bronchospasm, tachycardia, flushing, urticaria, injection-site induration) and anaphylactic reactions, reported more often with repeated/multiple-dose administration.
Discontinue and seek medical attention immediately if signs of an allergic reaction occur.
General Mitigation Strategies
The key risk is pituitary desensitization from continuous use - NEVER exceed 3 consecutive days of dosing. The very short half-life (2-40 minutes) means effects are brief but also means frequent dosing is required for sustained effect. Intermittent dosing (2-3x weekly) helps avoid receptor downregulation.
Post Cycle Therapy (PCT)
Gonadorelin IS a PCT compound - it stimulates natural LH/FSH release. Limited to short PCT protocols (1-3 days) due to desensitization risk. Often combined with SERMs (Nolvadex/Clomid) for complete PCT.
How It Works
Binds to GnRH receptors (GnRHR) on pituitary gonadotrope cells, activating phospholipase C-beta via G-protein coupling. This triggers IP3/DAG cascade, mobilizing intracellular calcium and activating PKC. Stimulates synthesis and release of LH (primary) and FSH (secondary). Pulsatile administration is required - continuous exposure causes pituitary desensitization and paradoxical suppression.
Fundamentals
Reference on the practices relevant to Gonadorelin: how they are done and where they go wrong. Not a recommendation to use it.
Common Stacks
- Gonadorelin + Nolvadex/Clomid for PCT (gonadorelin first 1-3 days, SERM throughout)
- Consider HCG instead if fertility preservation is priority
- On-cycle: 100mcg 2-3x weekly (Mon/Wed/Fri) for testicular maintenance
- DO NOT use continuously - causes opposite effect (suppression)
Legal Status
Prescription medication, not a controlled substance. FDA-approved for diagnostic use and fertility treatment, but human formulations have been discontinued in the USA, now available mainly from compounding pharmacies.
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
Gonadorelin (synthetic GnRH) is an LH releasing factor; CG, LH and their releasing factors are prohibited in males under S2.2 (both in- and out-of-competition). GnRH agonists/analogues are explicitly listed as examples.