Comparison
Melanotan II vs. Semax
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Research other
Research other
CAS no.
121062-08-6
80714-61-0
Molecular weight
1024.18 g/mol
813.92 g/mol
Half-life
1 h
0.3 h
Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2Met-Glu-His-Phe-Pro-Gly-ProMechanism of action
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.
Semax
Semax is a tetracosactide fragment analog without hormonal activity at MC2R. Proposed mechanisms include elevation of BDNF and NGF in hippocampus and striatum (in animal models), modulation of dopamine metabolism, and neuroprotective effects via anti-apoptotic pathways. A clear primary receptor is not established.
Evidence base
Highest evidence
Human trial
Human trial
Studies
9
4
of which in humans
5
2
Effects recorded
4
3
Open conflicts
1
1
Documented adverse events
6
1
Legal status
Full entries
Frequently asked questions
- What is the difference between Melanotan II and Semax?
- Melanotan II is classified as "Research other", while Semax is classified as "Research other". 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. Semax: Synthetic heptapeptide derived from the N-terminal fragment of adrenocorticotropic hormone (ACTH 4-10). Approved in Russia for ischaemic stroke, cognitive function and ADHD in children. Western phase-3 trials absent. This page contrasts both neutrally and source-based — with no usage or dosing recommendation.
- Which peptide is better supported by science, Melanotan II or Semax?
- The highest available evidence level is "Human trial" for Melanotan II and "Human trial" for Semax. 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 Melanotan II and Semax in Germany and the United States?
- Germany: Melanotan II — Unapproved, Semax — Unapproved. United States: Melanotan II — Unapproved, Semax — Unapproved. These are factual summaries with source and review date on the individual pages.