Comparison
Leuprorelin vs. Melanotan II
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Research other
Research other
CAS no.
53714-56-0
121062-08-6
Molecular weight
1209.4 g/mol
1024.18 g/mol
Half-life
3 h
1 h
Sequence
Pyr-His-Trp-Ser-Tyr-D-Leu-Leu-Arg-Pro-NHEtAc-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2Mechanism of action
Leuprorelin
Leuprorelin is a GnRH-receptor agonist. After binding to pituitary GnRH receptors, it first causes a transient surge in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release — the so-called flare. With continuous, non-pulsatile exposure the receptors are downregulated and desensitized, suppressing gonadotropin secretion and consequently lowering sex steroids (testosterone or estradiol) to low levels. This mechanism underlies the literature-described use in hormone-dependent conditions.
Melanotan II
Melanotan II binds non-selectively to all five melanocortin-receptor subtypes (MC1R-MC5R). Via MC1R in melanocytes, eumelanin synthesis is stimulated (pigmenting effect). Via MC4R and MC3R in the CNS, appetite, sexual function and blood pressure are modulated. The cyclic structure and D-amino acids increase stability compared to natural α-MSH.
Evidence base
Highest evidence
Human RCT
Human trial
Studies
4
9
of which in humans
4
5
Effects recorded
4
4
Open conflicts
1
1
Documented adverse events
3
6
Legal status
Full entries
Frequently asked questions
- What is the difference between Leuprorelin and Melanotan II?
- Leuprorelin is classified as "Research other", while Melanotan II is classified as "Research other". Leuprorelin: Leuprorelin (also leuprolide) is a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH/LHRH). It is an approved prescription medicine in several jurisdictions, including for advanced prostate cancer, endometriosis, uterine fibroids and central precocious puberty. This page neutrally summarizes the evidence base and legal status and is not a usage or dosing recommendation. Melanotan II: Cyclic hepta-peptide and non-selective melanocortin-receptor agonist. Originally researched at the University of Arizona as a sun-protection concept — never approved as a medicine. Widespread on the black market; regulatory warnings for cardiovascular and oncological risks. This page contrasts both neutrally and source-based — with no usage or dosing recommendation.
- Which peptide is better supported by science, Leuprorelin or Melanotan II?
- The highest available evidence level is "Human RCT" for Leuprorelin and "Human trial" for Melanotan II. A higher evidence level means more robust data, but says nothing about suitability for an individual. The full body of evidence is on each peptide's own page.
- What is the legal status of Leuprorelin and Melanotan II in Germany and the United States?
- Germany: Leuprorelin — Prescription, Melanotan II — Unapproved. United States: Leuprorelin — Prescription, Melanotan II — Unapproved. These are factual summaries with source and review date on the individual pages.