VIP: Complete Guide
Vasoactive Intestinal Peptide (VIP) is a 28-amino-acid neuropeptide belonging to the secretin/glucagon superfamily. It functions as a neurotransmitter and neuromodulator with broad immunomodulatory, vasodilatory, and neuroprotective properties. VIP is distributed throughout the central and peripheral nervous systems, gastrointestinal tract, and immune tissues, and is researched for inflammatory conditions, autoimmune diseases, and neurodegenerative disorders.
Last updated: 2026-01-29
Quick Facts
- Category
- therapeutic
- Also Known As
- Vasoactive Intestinal Peptide
- Related Goals
- inflammation, gut health
Who Researches VIP?
VIP is researched by people dealing with inflammatory and autoimmune conditions, particularly chronic inflammatory response syndrome (CIRS), mold illness, and pulmonary issues. It's a staple in the Shoemaker CIRS protocol. Researchers studying neuroimmune interactions, those investigating gut-brain axis signaling, and clinicians exploring treatments for conditions where conventional anti-inflammatories have failed will find VIP research relevant.
Research Peptides
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What Is VIP?
VIP was first isolated from porcine intestine in 1970 by Said and Mutt, who discovered its potent vasodilatory properties. Subsequent research revealed it as one of the most broadly distributed neuropeptides in the body, present in the brain, spinal cord, autonomic nervous system, gastrointestinal tract, lungs, and immune cells.
VIP's roles extend far beyond vasodilation: it regulates smooth muscle relaxation, exocrine/endocrine secretion, immune cell differentiation, circadian rhythm, and neurotrophic signaling. The peptide has gained particular attention in the integrative medicine community for its use in the Shoemaker protocol for chronic inflammatory response syndrome (CIRS) associated with mold and biotoxin exposure.
Mechanism of Action
VIP signals through two G-protein coupled receptors:
- VPAC1: Widely expressed in immune cells, lungs, liver, and brain — mediates anti-inflammatory and immunomodulatory effects
- VPAC2: Found in smooth muscle, CNS, and immune tissues — involved in circadian regulation and smooth muscle relaxation
Receptor activation stimulates cAMP production, which modulates:
- Th1/Th2 immune balance (shifts toward anti-inflammatory Th2 responses)
- Regulatory T cell (Treg) generation
- Macrophage and dendritic cell function
- Smooth muscle relaxation in vasculature and airways
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Dosage Overview
VIP is administered via intranasal spray or subcutaneous injection in clinical research and integrative medicine protocols:
| Route | Dose | Frequency | Application |
|---|---|---|---|
| Intranasal | 50 mcg per nostril | 4× daily | CIRS / Shoemaker protocol |
| Subcutaneous | 50–100 mcg | 1–2× daily | Research protocols |
VIP has a very short half-life (~1 minute in plasma), which is why intranasal delivery (providing direct CNS access) and frequent dosing are preferred.
Side Effects & Safety
- Nasal congestion: Common with intranasal use
- Diarrhea: VIP stimulates intestinal secretion; loose stools are common
- Hypotension: As a vasodilator, VIP can lower blood pressure — caution in patients with existing low BP
- Flushing: Related to vasodilation
- Headache: Reported in some protocols