Comparison
LL-37 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.
597562-32-8
121062-08-6
Molecular weight
4493.33 g/mol
1024.18 g/mol
Half-life
no data
1 h
Sequence
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTESAc-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2Mechanism of action
LL-37
LL-37 is a cationic, amphipathic helical peptide and the only member of the cathelicidin family in humans. It is generated by proteolytic cleavage from the C-terminal portion of the precursor protein hCAP18 (CAP-18). Mechanistically it associates with and can permeabilize microbial membranes; in addition it modulates immune cells, influences cytokine release, exerts chemotactic activity, and can bind extracellular self-DNA. Preclinical models have described both anti-inflammatory and pro-inflammatory effects, depending on concentration and tissue context.
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 trial
Human trial
Studies
4
9
of which in humans
1
5
Effects recorded
4
4
Open conflicts
1
1
Documented adverse events
0
6
Legal status
Full entries
Frequently asked questions
- What is the difference between LL-37 and Melanotan II?
- LL-37 is classified as "Research other", while Melanotan II is classified as "Research other". LL-37: LL-37 is the only known human cathelicidin, a 37-amino-acid antimicrobial peptide generated by cleavage of the precursor protein hCAP18. In research it plays a central role in innate immune defence and wound healing, yet acts in a context-dependent manner as both anti- and pro-inflammatory and has been linked to autoimmune processes. LL-37 is not an approved drug; the evidence base is predominantly basic and preclinical. 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, LL-37 or Melanotan II?
- The highest available evidence level is "Human trial" for LL-37 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 LL-37 and Melanotan II in Germany and the United States?
- Germany: LL-37 — Research only, Melanotan II — Unapproved. United States: LL-37 — Research only, Melanotan II — Unapproved. These are factual summaries with source and review date on the individual pages.