Vasoactive intestinal peptide (VIP, vasoactive intestinal polypeptide, PHM27) is a short peptide hormone endogenously produced in the gastrointestinal tract, pancreas, and brain of most vertebrate animals. Researchers have suggested that the peptide may exhibit potential to influence inflammation, particularly in the cases of neurodegenerative disease, pulmonary fibrosis, inflammatory bowel disease, and cardiac fibrosis. VIP has been suggested to act as an immune system regulator and has been classified by scientists as an anti-inflammatory peptide. It is of active scientific interest for its proposed ability to support cognitive function in the setting of neurodegenerative disease. VIP has been hypothesized to bind to class II G protein-coupled receptors.