What Is VIP? Vasoactive Intestinal Peptide Explained

VIP binds to two receptors, VPAC1 and VPAC2, which are found on smooth muscle, immune cells and lung tissue.

• Blood vessels and airways: it relaxes smooth muscle, widening blood vessels and airways.
• Inflammation: it lowers inflammatory signals such as TNF-α and IL-6 and supports regulatory immune cells.
• Lungs: it is abundant in the lungs and protects type II alveolar cells, which make surfactant.
• Gut: it stimulates water and electrolyte secretion. Tumors that overproduce VIP (VIPomas) cause severe watery diarrhea.

Pulmonary hypertension. Small early studies of inhaled VIP looked promising, but a randomized placebo-controlled trial published in 2010 found no significant improvement in patients with pulmonary arterial hypertension.

Sarcoidosis. A small 2010 study of inhaled VIP in lung sarcoidosis found reduced inflammatory signals in lung fluid, without clear clinical improvement.

COVID-19. NRx Pharmaceuticals tested intravenous aviptadil (Zyesami) in critically ill COVID-19 patients. The main trial missed its primary endpoint, and the FDA declined emergency use authorization twice, in 2021 and 2022.

CIRS. VIP nasal spray is used by some practitioners for chronic inflammatory response syndrome, often linked to mold exposure. The supporting data come from small, uncontrolled studies.

Because VIP widens blood vessels, the most common side effects in trials were flushing, low blood pressure, fast heart rate and diarrhea, especially with intravenous use. Inhaled and nasal forms tended to cause milder effects. People with low blood pressure or heart rhythm problems were usually excluded from studies.

No. VIP and aviptadil are not FDA-approved for any use in the U.S., and the FDA declined to authorize aviptadil for COVID-19. Aviptadil combined with phentolamine has been licensed in some European countries for erectile dysfunction. Some U.S. compounding pharmacies prepare VIP on prescription, while research-grade VIP is sold as a chemical labeled “not for human consumption.”

VIP vs PACAP. PACAP shares about 68% of its structure with VIP and acts on the same VPAC receptors plus its own PAC1 receptor. Drugs blocking PACAP are being developed for migraine.

VIP vs BPC-157. Both are linked to the gut, but VIP is a natural signaling molecule with human trials, while BPC-157 is a synthetic fragment studied mostly in rats.

Products sold as VIP by research suppliers are laboratory chemicals, not medicines. They are not made under drug manufacturing rules, so quality varies a lot between vendors. If you are evaluating a VIP supplier for lab research, these are the checks that matter:

• Batch-specific COA: the certificate should match the lot number on your vial, not a generic sample.
• Independent lab: testing should come from a named third-party lab, ideally with a way to verify the report online.
• Identity, not just purity: HPLC purity alone does not confirm the right molecule; look for mass spectrometry (MS) identity confirmation.
• Endotoxin and sterility results: these matter for any injectable research material.
• Correct fill amount: the measured content should be close to the labeled milligrams.

Our Trusted Sources page lists vendors we track, with current community codes. Our guide to reading a certificate of analysis explains each line of a COA.

• VIP is a 28-amino-acid neuropeptide that relaxes blood vessels and calms inflammation.
• Its synthetic form, aviptadil, failed to win FDA authorization for COVID-19.
• A randomized trial in pulmonary hypertension found no benefit.
• VIP nasal spray for CIRS is supported only by small uncontrolled studies.
• It is not FDA-approved for any use.

What is VIP peptide?

VIP (vasoactive intestinal peptide) is a natural 28-amino-acid neuropeptide that relaxes blood vessels and airways and helps regulate inflammation.

Is VIP FDA-approved?

No. VIP and its synthetic form aviptadil are not FDA-approved for any use in the U.S.

Does VIP work for COVID-19?

The main trial of intravenous aviptadil (Zyesami) missed its primary endpoint, and the FDA declined emergency use authorization twice.

What is VIP nasal spray used for?

Some practitioners use it for chronic inflammatory response syndrome (CIRS). The evidence comes from small uncontrolled studies.

What are VIP side effects?

Flushing, low blood pressure, fast heart rate and diarrhea, especially with intravenous use.

• Said & Mutt (1970), Science – Polypeptide with broad biological activity: isolation from small intestine
• Galiè et al. (2010), European Respiratory Journal – Effects of inhaled aviptadil (vasoactive intestinal peptide) in patients with pulmonary arterial hypertension
• Prasse et al. (2010), American Journal of Respiratory and Critical Care Medicine – Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosis
• FierceBiotech (2022) – FDA rejects NRx filing for emergency use of Zyesami in COVID-19