Gonadorelin
Gonadorelin (GnRH)
Gonadorelin is a synthetic decapeptide identical to endogenous gonadotropin-releasing hormone (GnRH), the hypothalamic hormone that stimulates pituitary release of LH and FSH. It is used clinically to assess hypothalamic-pituitary function, treat hypogonadotropic hypogonadism, and increasingly used in men on testosterone replacement therapy (TRT) to maintain testicular size and endogenous testosterone production by preventing LH suppression.
Mechanism of Action
Gonadorelin binds to GnRH receptors on pituitary gonadotroph cells, stimulating the synthesis and pulsatile release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This LH pulse drives Leydig cell testosterone production in men and supports follicular development in women. Critically, pulsatile administration maintains receptor sensitivity and stimulatory effect, whereas continuous administration paradoxically causes receptor downregulation and gonadotropin suppression.
Evidence by Health Goal(11 goals)
Dosing Protocols
Subcutaneous injection, typically alongside or between TRT injection days
Cycle: Continuous use while on TRT; may be cycled off with TRT cessation
Most common TRT-adjunct protocol to preserve testicular volume and intratesticular testosterone. Pulsatile dosing is essential - do not use as a continuous infusion. Some protocols use 50-100mcg 2-3x weekly for fertility preservation.
Administered as intranasal pulses mimicking physiological GnRH pulsatility, typically every 8 hours
Intranasal route has lower bioavailability (~1-3%) requiring higher doses. Primarily used in clinical settings for hypogonadotropic hypogonadism treatment; less common in research or wellness contexts than subcutaneous injection.
Safety & Side Effects
Gonadorelin has a well-characterized safety profile when used pulsatily at physiological doses, with most adverse effects being mild and transient; however, improper continuous dosing will cause the opposite of the intended effect due to receptor downregulation. It is a prescription medication in most jurisdictions and is widely available as a compounded pharmaceutical in the United States, requiring a valid prescription.
Possible Side Effects
- !Injection site redness, swelling, or mild pain (most common with subcutaneous use)
- !Flushing and transient warmth following administration
- !Headache, particularly after initial doses
- !Nausea or mild abdominal discomfort
- !Transient hypotension or lightheadedness post-injection
- !Ovarian hyperstimulation syndrome (OHSS) in women - potentially serious with fertility protocols
- !Anaphylactic or hypersensitivity reactions (rare but serious)
- !Paradoxical gonadotropin suppression with continuous or excessively frequent dosing
Interactions
- -Additive effect with exogenous testosterone (TRT) - intended combination but requires monitoring of LH, FSH, and testosterone levels
- -May interact with dopamine agonists (e.g., cabergoline, bromocriptine) which can alter GnRH receptor sensitivity and pituitary responsiveness
- -GnRH antagonists (e.g., cetrorelix, ganirelix) will competitively block gonadorelin's receptor binding and completely blunt its effect
- -Concurrent use with anabolic steroids (beyond prescribed TRT) may override gonadorelin's LH-stimulating effect due to profound HPG axis suppression
- -Progestins and estrogens can modulate pituitary sensitivity to GnRH, potentially altering LH and FSH response magnitude
Cost & Where to Buy
Compounded gonadorelin vials (typically 2mg or 5mg) from US compounding pharmacies range widely based on concentration and pharmacy. Pricing has increased following FDA scrutiny of compounded GnRH products; some patients pay out-of-pocket as insurance coverage is inconsistent.
Search on Amazon