peptidefix

VIP (vasoactive intestinal peptide)

Also: Vasoactive intestinal polypeptide, Aviptadil (synthetic form), Invicorp (with phentolamine)

Immune
Legal status United KingdomApproved medicineUnited StatesNot approvedAustraliaPrescription only
Research on peptidefix

5 papers: 5 human studies.

Listed suppliers United Kingdom3United States5Australia0 Europe3
Checked 2026-11-03

Legal status as understood on this date. Listed, not endorsed. How we list.

Summary

Vasoactive intestinal peptide is a 28-amino-acid hormone and neurotransmitter made in the gut, pancreas and nervous system. It widens blood vessels, relaxes smooth muscle and modulates inflammation. The synthetic form, aviptadil, is a licensed medicine in the UK in combination with phentolamine (Invicorp) for erectile dysfunction, and has been studied by inhalation and infusion for lung conditions. Unlike most peptides on this site, VIP is a natural human hormone with a long research history.

What it targets

VIP acts through VPAC1 and VPAC2 receptors on blood vessels, airway and gut smooth muscle, and immune cells. Human studies linked here include: a single inhaled dose in 20 patients with pulmonary hypertension, which produced a small, short-lived fall in pulmonary vascular resistance; a placebo-controlled trial of intravenous aviptadil in 196 patients with COVID-19 respiratory failure, which did not meet its primary endpoint though the authors reported secondary survival findings; a skin-blood-flow physiology study in 43 volunteers; and observational studies relating blood VIP levels to inflammatory bowel disease activity and, in 37 healthy women, to anxiety and depression scores. None of the linked studies is a treatment trial in a condition the peptide is licensed for.

pulmonary hypertension (inhaled, n=20)COVID-19 respiratory failure (RCT, n=196, primary endpoint not met)skin blood flow mechanism (healthy volunteers)inflammatory bowel disease activity marker (observational)mood and brain structure (observational, healthy women)

Clinical Research

Inhalation of vasoactive intestinal peptide in pulmonary hypertension
Leuchte HH, Baezner C, Baumgartner RA, et al. (2008). European Respiratory Journal. human patients with pulmonary hypertension, n=20, single inhaled dose during catheterisation
The Use of IV Vasoactive Intestinal Peptide (Aviptadil) in Patients With Critical COVID-19 Respiratory Failure: Results of a 60-Day Randomized Controlled Trial
Youssef JG, Lavin P, Schoenfeld DA, et al. (2022). Critical Care Medicine. human patients with COVID-19 respiratory failure, randomised placebo-controlled trial, n=196, ten US hospitals
Mechanisms of vasoactive intestinal peptide-mediated vasodilation in human skin
Wilkins BW, Chung LH, Tublitz NJ, Wong BJ, Minson CT (2004). Journal of Applied Physiology. human healthy volunteers, n=43, intradermal microdialysis
Vasoactive intestinal polypeptide plasma levels associated with affective symptoms and brain structure and function in healthy females
Simon RA, Barazanji N, Jones MP, et al. (2021). Scientific Reports. human healthy females, n=37, observational (plasma VIP, questionnaires, MRI)
Vasoactive intestinal peptide as a laboratory supplement to clinical activity index in inflammatory bowel disease
Duffy LC, Zielezny MA, Riepenhoff-Talty M, et al. (1989). Digestive Diseases and Sciences. human adults with inflammatory bowel disease, n=115 (48 ulcerative colitis, 67 Crohn's), observational over six months

All research on VIP (vasoactive intestinal peptide) →

Suppliers stocking VIP (vasoactive intestinal peptide)

11 of the 49 listed suppliers. Each row opens its full listing.

CertaPeptides Romania All CertaPeptides products are sold exclusively for in-vitro laboratory research. They are not approved for human consumption, veterinary use, therapeutic applications… Core Peptides United States Products are for laboratory, research or analytical purposes only, and are not for human consumption. Direct Peptides United States All products are sold strictly for laboratory research use only and are not for human or animal consumption. Direct Peptides is a chemical supplier, not a compounding pharmacy or 503A/503B facility. Eurolabs Peptides Germany For research purposes only. Not for human consumption. Licensed Peptides United States Supplied strictly for laboratory research use only. Not intended for human consumption, veterinary use, therapeutic applications, or diagnostic use. No dosing instructions are provided. Midshire Labs United Kingdom All Midshire Labs products are sold strictly for research purposes only. They are not intended for human consumption, medical, veterinary, or diagnostic use. Nationwide Peptides United States For Research Use Only. Products are not intended for human or animal consumption, ingestion, injection, or any form of administration. Nupex United Kingdom Products sold on nupex.co.uk are for research purposes only and are not for human or veterinary use. Protide Health United States All products are supplied for laboratory research only and are not for human or animal consumption, medical use, veterinary use, or any therapeutic, diagnostic, or clinical purpose. Research Peptides Europe Ireland Lyophilised peptides are for research / laboratory use only — not for human use. Tide Labs United Kingdom For laboratory research use only. Not for human or veterinary use.