VIP

A 28-amino-acid neuropeptide (Vasoactive Intestinal Peptide, CAS 40077-57-4), a member of the secretin/glucagon superfamily, widely distributed in the central and peripheral nervous systems. Agonizes the VPAC1 and VPAC2 class-B G-protein-coupled receptors to drive vasodilation, immune modulation, and circadian-clock signaling. Studied as a research tool in neuroendocrine and inflammatory-pathway models; the VPAC2-selective analog aviptadil received FDA Breakthrough Therapy designation for respiratory failure from COVID-19 in 2020. Native VIP itself is not FDA-approved.