GnRH · LH-RH · Factrel
Native GnRH — testicular function and fertility on TRT.
FDA
Compounding Allowed
WADA
Banned
HALF-LIFE
~2–4 minutes
ROUTE
SubQ injection or pulsed IV
SCHEDULE
2× weekly
In Plain English
Native GnRH — testicular function and fertility on TRT.
Status & Legality
What do these mean?TRT adjunct
Testicular size maintenance
Male fertility
HPG axis preservation
Gonadorelin is synthetic GnRH that stimulates LH and FSH release from the pituitary, maintaining testicular function, spermatogenesis, and testosterone production. It's the preferred TRT adjunct for fertility preservation and testicular atrophy prevention, replacing the off-label use of HCG following regulatory changes.
Injection site reactions
Headache
Nausea (rare)
Flushing
Dosing less than 2× weekly — at lower frequencies, LH stimulation becomes insufficient for consistent spermatogenesis maintenance
Expecting it to be identical to HCG — Gonadorelin works upstream at the pituitary level (not directly on Leydig cells like HCG) and may take longer to show testicular effects
Stopping suddenly during TRT without a transition plan — abrupt discontinuation leads to rapid testicular atrophy return
Testosterone (TRT) — designed to be co-administered; this is the clinical standard for maintaining testicular function during TRT
GnRH antagonists (ganirelix, cetrorelix) — directly block GnRH receptors; counterproductive if combined
Anticoagulants — monitor injection sites for bruising; no significant pharmacokinetic interaction
Gonadorelin replaced HCG as the preferred TRT adjunct for maintaining fertility and testicular size after HCG regulatory changes in the US. The pulsatile mechanism (2–3×/week SubQ) is more physiological than HCG's direct LH receptor agonism. For anyone prioritizing fertility or testicular function during TRT, Gonadorelin is the current standard of care.
KISSPEPTIN-10
Gonadotropin-releasing hormone trigger — libido and fertility.
TRIPTORELIN
GnRH agonist — PCT and hormone axis resetting.
LEUPROLIDE
GnRH agonist — chemical castration therapy and endometriosis.
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Stats
Sources & Studies
Crowley WF Jr. et al., N Engl J Med, 1980