Gonadorelin (Factrel / Lutrelef)
Synthetic 10-aa GnRH – direct pituitary GnRH-R stimulus, LH/FSH release. FDA Factrel 1982 (US-discontinued 2008); EMA Lutrelef pulsatile-pump Rx for hypothalamic hypogonadism. Continuous dose paradox-downregulation in prostate cancer therapy.
WHAT IS GONADORELIN (FACTREL / LUTRELEF)?
Detailed overview
Gonadorelin is a synthetic replica of the 10-amino-acid decapeptide GnRH (gonadotropin-releasing hormone, also known as LHRH) – sequentially IDENTICAL to endogenous hypothalamic GnRH (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH₂). The hypothalamic arcuate nucleus + median eminence GnRH neurons naturally secrete GnRH in a ~90-120-minute pulsatile pattern into the hypothalamo-pituitary portal circuit; SC or IV injection of Gonadorelin replicates this pulse signal and binds directly to the GnRH receptor on pituitary anterior-lobe gonadotrope cells → LH + FSH release. Clinical history: FDA Factrel approval (Wyeth 1982) – original indication was pituitary LH/FSH diagnostic stimulation testing (to discriminate hypothalamic vs pituitary hypogonadism). US discontinued 2008 (commercial-viability reasons, NOT safety). EMA Lutrelef (Ferring) remains available across the EU on a pulsatile-pump protocol as an Rx for hypothalamic hypogonadism (Kallmann syndrome + acquired GnRH deficiency). Paradox mechanism with continuous dosing: a chronically elevated GnRH signal (vs pulsatile) downregulates the GnRH receptor → this is the mechanism of GnRH-agonist therapy in prostate cancer treatment (Lupron/Leuprolide, Zoladex/Goserelin) – same molecular family, opposite-direction effect based on the dosing pattern. AAS-PCT context: Gonadorelin sits 1 axis level below Kisspeptin-10 (Kisspeptin upstream GPR54 → GnRH stimulus; Gonadorelin direct pituitary GnRH-R stimulus). The practical problem is identical: pulsatile-pump impractical for self-administration, single bolus has limited efficacy. UGL peptide sourcing is standard; EU pharmacy availability via Lutrelef protocol.
Mechanism
Direct pituitary anterior-lobe GnRH-receptor (LHRH-R) agonist → LH + FSH release → testicular Test
Dosing
100 mcg SC every 90-120 min (pulse-pump, impractical) or 100-500 mcg SC bolus pre-cycle (community protocol, limited efficacy)
Half-life
~10-40 min (very short – pulsatility pattern is essential)
Onset
LH/FSH spike 15-60 min after SC
Legal status
FDA Factrel withdrawn 2008; EMA Lutrelef Ferring Rx (pulsatile-pump hypothalamic hypogonadism); WADA S2 Peptide Hormones banned
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 6
- Hypersensitivity reactions, including rare anaphylaxis and antibody formation with repeated parenteral dosing (documented in FDA Factrel labeling: generalized urticaria, bronchospasm).
- Injection-site reactions: pain, redness, itching, swelling, rarely phlebitis; with pulsatile-pump protocols, ongoing cannula-site inflammation and infection risk.
- Headache, flushing, mild dizziness and nausea, often immediately post-injection, transient.
- Abdominal pain and discomfort, less commonly gastric complaints (reported in FDA Factrel labeling).
- With continuous (non-pulsatile) or prolonged dosing, paradoxical GnRH-receptor downregulation and desensitization: LH/FSH suppression and falling testicular testosterone (the chemical-castration mechanism of GnRH-agonist therapy).
- With pulsatile-pump protocols, overstimulation from increased gonadotropin drive: multiple follicular development and risk of ovarian hyperstimulation in women; transient secondary estradiol rise in men.
Contraindications · 6
- Known hypersensitivity to gonadorelin or GnRH analogues (prior anaphylactic or severe allergic reaction).
- Hormone-sensitive tumor or suspicion thereof (gonadotropin- or sex-hormone-dependent tumor) where LH/FSH stimulation is contraindicated.
- Pituitary adenoma, especially prolactinoma or gonadotroph tumor: GnRH stimulation carries a risk of pituitary apoplexy and abrupt hormone surge.
- Concurrent GnRH-agonist therapy (leuprolide/Lupron, goserelin/Zoladex): receptor-occupancy overlap and amplification of paradoxical receptor downregulation – not recommended.
- Pregnancy and breastfeeding: no established safety, axis stimulation not indicated; in fertility treatment only under endocrinologist supervision.
- Not indicated for self-treatment as AAS-PCT: pulsatile pump is impractical for self-injection, bolus protocol is evidence-poor, and lack of sterile technique creates infection risk.
Related Performance Compounds
Same therapeutic category
Studies
Related research and clinical findings
Factrel (gonadorelin hydrochloride) for injection – FDA Label
Wyeth-Ayerst Laboratories
Lutrelef (gonadorelin acetate) – EMA Summary of Product Characteristics
Ferring Pharmaceuticals
Therapeutic effects of a pulsatile GnRH pump on adult male patients with congenital hypogonadotropic hypogonadism (CHH): a retrospective study.
Jiang H, Li BJ, Jin DC
[Effect and safety of pulsatile GnRH therapy for male congenital hypogonadotropic hypogonadism].
Niu YH, Xu H, Chen YW
Telegram
Have a question about Gonadorelin (Factrel / Lutrelef)?
Reach out to an advisor on Telegram. Performance compounds are presented with a harm-reduction approach, based on peer-reviewed evidence.
Personalized consultation
Want a detailed conversation tailored to your data?
Fill out the prep intake form (your goals, training and health data), and the advisor prepares from it to give genuinely personalized guidance.
Fill out the form~5–7 min · prep questionnaire · confidential · GDPR-compliant
The information here is for educational and scientific purposes only. Performance-enhancing compounds (AAS, prohormones, stimulants, doping agents) are illegal without prescription in Hungary and most of the EU, and carry serious health and legal risks. WADA bans them in competitive sport. This is NOT a usage guide, and we do not encourage any illegal use. If you do use them, medical supervision and regular bloodwork are ESSENTIAL. Severe endocrine, cardiovascular, hepatic and psychiatric side effects are possible.