Comparison
Argireline vs. Melanotan II
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Cosmetic
Research other
CAS no.
616204-22-9
121062-08-6
Molecular weight
888.99 g/mol
1024.18 g/mol
Half-life
no data
1 h
Sequence
Ac-Glu-Glu-Met-Gln-Arg-Arg-NH2Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2Mechanism of action
Argireline
Argireline is a synthetic hexapeptide whose sequence corresponds to the N-terminus of the SNAP-25 protein. In vitro it has been shown to competitively inhibit SNARE complex formation (necessary for vesicle fusion in neurotransmitter release). Topical application is intended — given very limited skin permeation — to attenuate cholinergic signalling at the neuromuscular endplate. The effect is orders of magnitude weaker than intramuscular botulinum toxin; the clinical translatability of the in-vitro observations to the skin microenvironment is contested.
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
3
5
of which in humans
2
5
Effects recorded
3
4
Open conflicts
1
0
Documented adverse events
1
3