Signal peptides: what works and what doesn't
Matrixyl (palmitoyl pentapeptide-4): 19 peer-reviewed studies, consistent evidence for collagen Type I synthesis stimulation. In head-to-head trials at 8 weeks, Matrixyl 3000 achieves 68% of retinol's wrinkle-reduction efficacy with zero irritation — making it superior for sensitive skin. Argireline (acetyl hexapeptide-3): reduces dynamic wrinkles via neurotransmitter inhibition. Most evidence is company-sponsored; effect size modest but meaningful in periorbital lines.