– Acetyl tetrapeptide-15 Acetate (Skinasensyl Acetate), a synthetic peptide used in cosmetic products for sensitive skin, is an endomorphin-2 derivative that extends the range of neuronal excitability thresholds in the μ-opioid receptor via an endorphin-like pathway, and can be used to study inflammatory and neuropathic pain produced by skin hyperreactivity. Inflammatory and neuropathic pain produced by skin hyperresponsiveness.