Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of Gonadorelin and Melanotan II — mechanism, side effects, legal status, and pricing.
Gonadorelin is a synthetic decapeptide identical to endogenous gonadotropin-releasing hormone (GnRH/LHRH; sequence pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2). It was historically FDA-approved as Factrel (diagnostic GnRH stimulation test) and Lutrepulse (pulsatile IV pump for hypothalamic amenorrhea); both products are discontinued in the US. Gonadorelin remains on the FDA Category 1 bulk substances list and is widely compounded, most commonly as an off-label adjunct to TRT intended to preserve HPG-axis signaling.
Melanotan II (MT-II) is a cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH) — Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 — developed at the University of Arizona in the 1980s by Hruby, Hadley, and colleagues as a candidate photoprotection / sunless-tanning agent. It has never been approved by the FDA or any other regulator for any indication; clinical development was abandoned and it is sold only via grey-market research-chemical channels. Genuine safety signals have been reported, including darkening of existing moles, eruptive atypical nevi, and case reports of new primary melanoma in young tanning-seeking users.
Gonadorelin
Melanotan II
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
Gonadorelin
Melanotan II
COA corpus from Disclosed Labs — independently tested batches only.
Gonadorelin
4
COAs
99.6%
Avg purity
2
Labs
Melanotan II
60
COAs
99.7%
Avg purity
12
Labs
The historical FDA-approved gonadorelin products (Factrel for diagnostic pituitary testing; Lutrepulse for pulsatile ovulation induction in hypothalamic amenorrhea) are discontinued commercially, but gonadorelin remains on the FDA Category 1 bulk substances list and is compounded under 503A/503B. Pulsatile pump delivery (every 60–120 minutes) is the clinical gold standard for hypothalamic amenorrhea and congenital hypogonadotropic hypogonadism, with systematic-review evidence supporting high ovulation rates (Tranoulis 2018, PMID 29605411) and faster spermatogenesis versus cyclical hCG/hMG in CHH men (Zhang 2018/2019, PMID 30569789; Büchter 1998, PMID 9758439). Use as a TRT adjunct in place of hCG is widespread in men's-health practice but is off-label and has limited dedicated controlled-trial data; its ability to maintain intratesticular testosterone once the HPG axis is fully suppressed by exogenous testosterone has not been rigorously established.
Key references
Melanotan II was developed by Hruby, Hadley, and colleagues at the University of Arizona in the 1980s. The seminal Phase I clinical study is Dorr et al. (Life Sciences, 1996; PMID 8637402), a pilot trial in three healthy male volunteers that documented dose-dependent pigmentation together with nausea, a 'stretching and yawning complex,' and spontaneous penile erections — the MC4R sexual-arousal signal that later motivated the development of bremelanotide (PT-141/Vyleesi). MT-II itself was never advanced to Phase III and has never received regulatory approval in any jurisdiction. As unregulated consumer use expanded through the 2000s, dermatology literature accumulated safety signals: Langan et al. (BMJ 2009, PMID 19174439) reported changes in moles among young users of unlicensed 'sun tan jab' preparations; Cardones & Grichnik (Arch Dermatol 2009, PMID 19380666) described alpha-MSH-induced eruptive atypical nevi in a patient with dysplastic nevi and prior melanoma who used MT-II; Evans-Brown et al. (BMJ 2009, PMID 19224885) documented widespread unregulated population use. Further case reports describe new primary cutaneous melanoma in young MT-II users and rare rhabdomyolysis. Regulators (FDA, UK MHRA, Australian TGA) have explicitly warned against use. Note: the Barnetson et al. 2006 photoprotection study (J Invest Dermatol, PMID 16763547) evaluated the related linear analog [Nle4-D-Phe7]-alpha-MSH (afamelanotide / Melanotan-I), not MT-II. Category 2 classification reflects documented safety concerns from non-selective melanocortin activation combined with oncologic signals.
Gonadorelin (Hormone) and Melanotan II (Cosmetic) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references
Disclosed Labs