Vasoactive Intestinal Peptide (VIP)

Overview

Vasoactive Intestinal Peptide (VIP) is a 28-amino acid neuropeptide of the secretin/glucagon family, widely distributed in the CNS and peripheral nervous system. It is a potent vasodilator, bronchodilator, and immunomodulator. Synthetic VIP (aviptadil) has been investigated in clinical trials for COVID-19-associated acute respiratory failure; it is NOT FDA-approved. Intranasal compounded VIP is used off-label in the controversial 'CIRS' (Chronic Inflammatory Response Syndrome) / mold-illness protocol popularized by Ritchie Shoemaker — CIRS is not a mainstream medical diagnosis.

Mechanism of Action

VIP binds the Gs-coupled VPAC1 and VPAC2 receptors expressed on immune cells, neurons, and smooth muscle, elevating cAMP. It suppresses pro-inflammatory cytokines (TNF-α, IL-6, IL-12) and iNOS, promotes Th2-polarized and regulatory T-cell responses, and relaxes vascular and airway smooth muscle (potent vasodilator/bronchodilator).

Research Summary

Delgado, Pozo, and Ganea (Pharmacol Rev 2004; PMID 15169929) reviewed VIP's role as an endogenous anti-inflammatory mediator via VPAC1/VPAC2 signaling. For COVID-19 ARDS, Youssef et al. (Crit Care Med 2022; PMID 36044317) ran a 60-day RCT of IV aviptadil and reported a survival signal in secondary analysis but missed the primary endpoint. The larger NIH-sponsored TESICO trial (Lancet Respir Med 2023; PMID 37348524) was stopped for futility and found no benefit of aviptadil. The FDA granted aviptadil Fast-Track designation in 2020 but DENIED the Breakthrough Therapy designation request and DECLINED an Emergency Use Authorization; aviptadil remains investigational and is NOT FDA-approved as of April 2026. Intranasal compounded VIP used in Shoemaker's CIRS/mold-illness protocol lacks RCT evidence and is not mainstream medical practice.

Vendors selling Vasoactive Intestinal Peptide (VIP)

Scored vendors carrying Vasoactive Intestinal Peptide (VIP), ranked by trust grade. Grades are computed from indexed Certificates of Analysis. Full $/mg pricing is on the comparison page.

Reported Side Effects

• Transient hypotension (dose-limiting with IV)
• Flushing
• Diarrhea / increased GI motility
• Nasal irritation (intranasal route)
• Headache

Research References

• The significance of vasoactive intestinal peptide in immunomodulation (Delgado, Pozo, Ganea, Pharmacol Rev) (2004)
• 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 et al., Crit Care Med) (2022)
• Intravenous aviptadil and remdesivir for COVID-19-associated hypoxaemic respiratory failure (TESICO): a randomised, placebo-controlled trial (Lancet Respir Med) (2023)

Frequently asked questions

Has Vasoactive Intestinal Peptide (VIP) been independently lab-tested?

Disclosed Labs has collected 34 Certificates of Analysis (COA) for Vasoactive Intestinal Peptide (VIP) from 10 independent testing labs. 20 vendors have submitted material for testing. Products average 99.4% tested purity across the corpus. Full testing data is available at https://www.disclosedlabs.com/peptides/vip/testing.

What is the average purity of Vasoactive Intestinal Peptide (VIP) on the market?

Based on 34 COAs analyzed by Disclosed Labs, Vasoactive Intestinal Peptide (VIP) products average 99.4% (±0.3%) tested purity. Individual vendor results vary; see per-vendor COA data at https://www.disclosedlabs.com/peptides/vip/coas.

Which labs have tested Vasoactive Intestinal Peptide (VIP)?

Independent labs that have tested Vasoactive Intestinal Peptide (VIP) include: ILS Labs (Grade A). Full lab credibility grades and profiles are at https://www.disclosedlabs.com/labs.

Where can researchers source Vasoactive Intestinal Peptide (VIP)?

8 vendors with Disclosed Labs trust grades currently list Vasoactive Intestinal Peptide (VIP), including Instant Peptides, Glacier Aminos, Ion Peptide. Compare live prices and lab-verified COAs at https://www.disclosedlabs.com/prices/vip.

How does Vasoactive Intestinal Peptide (VIP) work?

VIP binds the Gs-coupled VPAC1 and VPAC2 receptors expressed on immune cells, neurons, and smooth muscle, elevating cAMP. It suppresses pro-inflammatory cytokines (TNF-α, IL-6, IL-12) and iNOS, promotes Th2-polarized and regulatory T-cell responses, and relaxes vascular and airway smooth muscle (potent vasodilator/bronchodilator).

What does the research say about Vasoactive Intestinal Peptide (VIP)?

Delgado, Pozo, and Ganea (Pharmacol Rev 2004; PMID 15169929) reviewed VIP's role as an endogenous anti-inflammatory mediator via VPAC1/VPAC2 signaling. For COVID-19 ARDS, Youssef et al. (Crit Care Med 2022; PMID 36044317) ran a 60-day RCT of IV aviptadil and reported a survival signal in secondary analysis but missed the primary endpoint. The larger NIH-sponsored TESICO trial (Lancet Respir Med 2023; PMID 37348524) was stopped for futility and found no benefit of aviptadil. The FDA granted aviptadil Fast-Track designation in 2020 but DENIED the Breakthrough Therapy designation request and DECLINED an Emergency Use Authorization; aviptadil remains investigational and is NOT FDA-approved as of April 2026. Intranasal compounded VIP used in Shoemaker's CIRS/mold-illness protocol lacks RCT evidence and is not mainstream medical practice.