Identity
Vialox, INCI name Pentapeptide-3 (also written Pentapeptide-3V), is a synthetic peptide used as a cosmetic "expression-line" active. It is the third distinct mechanism in the "topical Botox" category carried in this register — and the one that most directly mimics a paralytic agent.
Mechanism (as proposed)
Vialox is designed as a curare-mimetic: a competitive antagonist at the postsynaptic acetylcholine receptor on the muscle. Where Argireline interferes with the SNARE machinery that releases the neurotransmitter, and Leuphasyl modulates enkephalin receptors that regulate that release, Vialox is aimed at the receiving end — blocking the receptor so the acetylcholine signal can't land. Curare, the arrow poison, works at exactly this site; Vialox borrows the concept in reversible, topical form. The mechanism is coherent in principle, but the honest gaps are the class's usual pair: receptor-blocking shown in models rather than on skin, and real doubt about whether enough peptide reaches the neuromuscular junction through intact skin at cosmetic concentrations.
Reading the evidence honestly
As with the rest of the category, the clinical record is small and largely supplier-associated, and independent replication is limited — hence the D grade. The "works like Botox" claim is graded F: there is no head-to-head comparison with botulinum toxin, and the mechanism (reversible receptor competition) is fundamentally different from the toxin's enzymatic action. Lawful and well tolerated as a cosmetic; the constraint is the claim, not the sale.