VIP

What VIP is

VIP (vasoactive intestinal peptide) is a 28-residue peptide hormone of the secretin-glucagon family, isolated from porcine small intestine by Said and Mutt in 1970. It is produced by neurons of the gut, lung, brain and immune tissues, acts through the VPAC1 and VPAC2 receptors, and is characterised in the literature as a neuropeptide with vasodilator, secretory and immune-regulatory roles. The synthetic peptide carries the international non-proprietary name aviptadil and has a long regulatory history, including an approved combination product in some countries and a large COVID-19 trial programme. It is supplied here as a lyophilized (freeze-dried) powder for laboratory research.

What the research examines

Receptor pharmacology. Cell and tissue studies characterised the binding of VIP to the VPAC1 and VPAC2 receptors, both G-protein-coupled receptors signalling through cyclic AMP, and mapped receptor distribution in lung, gut, blood vessels and immune cells. This work underlies the IUPHAR classification of the VIP and PACAP receptor family and the design of receptor-selective analogues.

Immune regulation. Studies in cultured macrophages, T cells and dendritic cells, and in mouse models of inflammatory and autoimmune disease, measured cytokine production, regulatory T-cell induction and disease scores after exposure to VIP, and reported lower output of inflammatory cytokines in several of these models.

Pulmonary conditions. Pilot studies examined aviptadil in people with primary pulmonary hypertension (n=8, reported in 2003) and pulmonary sarcoidosis (n=20, reported in 2010), measuring pulmonary haemodynamics, exercise capacity, and cytokine production and regulatory T cells in bronchoalveolar lavage. These were small, uncontrolled studies and were not followed by an authorised product.

COVID-19 respiratory failure. Two randomised, placebo-controlled trials examined aviptadil in people with COVID-19-associated respiratory failure. A 196-participant industry trial (2:1 randomisation) measured survival free of respiratory failure at day 60 and reported no significant difference on that primary endpoint; the NIH-sponsored TESICO trial (461 analysed) measured a six-category ordinal outcome at day 90 and reported no significant difference from placebo.

Aviptadil combined with phentolamine is an approved medicine for erectile dysfunction in some countries (Invicorp, approved in Denmark in 1998; UK marketing authorisation 2015). Its COVID-19 programme did not meet its primary endpoints in placebo-controlled trials and a US emergency-use application was not granted, although India granted emergency-use approval in 2022. The research-grade material sold here is not a medicine, and this page makes no claims about effects in humans.

Selected literature

• Said SI, Mutt V Science, 1970, original isolation. doi:10.1126/science.169.3951.1217
• Delgado M, Ganea D Amino Acids, 2011, review of immune studies. doi:10.1007/s00726-011-1184-8
• Petkov V, et al. Journal of Clinical Investigation, 2003, uncontrolled pilot study, 8 participants. doi:10.1172/JCI17500
• Prasse A, et al. American Journal of Respiratory and Critical Care Medicine, 2010, uncontrolled pilot study, 20 participants. doi:10.1164/rccm.200909-1451OC
• Brown SM, et al. The Lancet Respiratory Medicine, 2023, phase 3 randomised placebo-controlled trial. doi:10.1016/S2213-2600(23)00147-9

Every reference is listed with its DOI in the research library.

Handling in the laboratory

Store sealed at 2–8 °C for routine use or frozen for long-term storage, protected from light and moisture. Let the vial reach room temperature before opening. See Storage and handling of lyophilized research peptides.