1. Clinical Overview

Molecule: 28-amino acid neuropeptide hormone. Found in GI tract, CNS, pulmonary vasculature, immune cells.

Classification: Anti-inflammatory neuropeptide • Bronchodilator • Smooth muscle relaxant • Autonomic regulator • Th1/Th2 modulator • Neurovascular/microcirculatory agent

Widely used in CIRS protocols and complex autonomic/neuroimmune dysfunction. Potent effects on anti-inflammatory signaling, bronchodilation, gut motility/absorption, autonomic regulation, and neurovascular function.

2. Mechanisms of Action

2.1 VPAC1 & VPAC2 Receptor Activation

cAMP signaling, anti-inflammatory immunity, smooth muscle relaxation, bronchodilation, enhanced mucus clearance, vasodilation.

2.2 Anti-Inflammatory Cytokine Modulation

Reduces TNF-α, IL-6, IL-1β, IL-12, NF-κB. Increases IL-10 and Treg function. Downregulates chronic systemic inflammation, restores immune balance.

2.3 Neuroimmune & Autonomic

Parasympathetic activation, heart rate variability, vagal tone, stress reactivity, neurovascular stability. Dysautonomia, POTS, CIRS-related autonomic dysfunction.

2.4 Pulmonary & Bronchodilatory

Natural bronchodilator: relaxes bronchial smooth muscle, pulmonary vasodilation, reduced airway inflammation, improved O₂ utilization. COPD, asthma, pulmonary hypertension.

2.5 Gut Motility & Secretory

Smooth muscle relaxation, gut motility, bile flow, pancreatic enzyme secretion, mucosal healing. IBS, dysmotility, gut–brain axis dysfunction.

3. Clinical Applications

3.1 CIRS

Final step in many CIRS protocols: inflammation reduction, cognitive improvement, sleep normalization, improved autonomic tone, mitochondrial biogenesis markers, reduced symptom clusters.

3.2 Autonomic Dysfunction

Heart rate variability, parasympathetic tone, stress response, neurovascular perfusion. POTS, Long-COVID dysautonomia, post-viral instability.

3.3 Pulmonary

Bronchodilation, airflow, pulmonary vascular dilation, exercise tolerance. COPD, pulmonary hypertension, asthma, chronic bronchitis.

3.4 GI Motility

Smooth muscle relaxation, intestinal secretions, motility rhythm, pancreatic enzymes. IBS, SIBO-associated dysmotility, post-infectious GI dysfunction.

3.5 Cognitive & Neuroimmune

Neuroprotective: reduced microglial activation, decreased cytokine signaling, improved neurovascular flow. Post-inflammatory cognitive dysfunction, brain fog, stress-induced neurocognitive impairment.

4. Administration & Dosing

Reconstitution

5 mg vial: 2 mL BS → 2.5 mg/mL, or 5 mL → 1 mg/mL (preferred for precision). Gently swirl — do not shake.

Intranasal (CIRS / Autonomic): 50 mcg/spray, 1–2 sprays, 1–4× daily × 30–90 days
Neuroimmune / Cognitive: 1 spray (50–100 mcg) 1–2× daily × 4–8 weeks
Pulmonary: 1 spray 2–3× daily (increase during flares)
SC Option: 50–200 mcg daily or 100 mcg 3×/wk
Titration: Start 50 mcg daily, increase q3–5 days to response or max tolerated

5. Clinical Decision Trees

Tree 1 — Candidate Selection

CIRS? → VIP strongly indicated

Dysautonomia / POTS? → Likely beneficial

Pulmonary disease? → Consider VIP

GI dysmotility? → Supportive role

Unexplained inflammation? → Case-by-case

Tree 2 — Route Selection

Environmental illness / neuroimmune → Intranasal

Pulmonary / respiratory → Intranasal

GI / systemic inflammatory → SC

Cognitive performance → Intranasal

6. Safety, Contraindications & Monitoring

Contraindications

Side Effects

Common: Transient flushing, lightheadedness, nasal irritation, mild headache, loose stools, temporary BP drop. Rare: Tachycardia, anxiety/jitteriness, worsened asthma in sensitive patients.

Monitoring

Legal Disclaimer

This document is provided solely for educational and informational purposes. VIP (Vasoactive Intestinal Peptide) and other peptides are not FDA-approved drugs. Peptide Protocol Portal makes no representations or warranties. By using this document, the reader agrees that Peptide Protocol Portal shall not be held liable. Use at your own risk.

References — VIP

Foundational VIP Physiology
1. Said, S. I., & Mutt, V. Discovery of VIP. Science, 169(3951), 1217–1218 (1970).
2. Harmar, A. J., et al. VPAC1/VPAC2 receptor biology. Pharmacol Rev, 50(3), 265–290 (1998).
3. Delgado, M., & Ganea, D. VIP/PACAP anti-inflammatory neuropeptides. Trends Immunol, 22(1), 11–17 (2001).
Anti-Inflammatory & Immune
4. Ganea, D., & Delgado, M. Th1/Th2 immune balance. J Immunol, 165(1), 547–556 (2000).
5. Leceta, J., et al. Endogenous anti-inflammatory cytokine. Immunol Today, 21(6), 267–272 (2000).
6. Gomariz, R. P., et al. Treg activation. Ann NY Acad Sci, 992(1), 97–104 (2003).
Pulmonary & Respiratory
7. Groneberg, D. A., et al. Asthma/airway inflammation. Allergy, 60(9), 1164–1170 (2005).
8. Said, S. I. Endogenous bronchodilator. Am J Respir Crit Care Med, 158, 1623–1630 (1998).
Cognitive & Neuroimmune
9. Dickson, L., & Finlayson, K. VPAC receptors in CNS. Br J Pharmacol, 152(4), 689–701 (2007).
10. Sherwood, N. M., et al. Neural plasticity. Gen Comp Endocrinol, 148(2), 267–273 (2006).
CIRS & Environmental Illness
11. Shoemaker, R. C., et al. VIP nasal spray in CIRS. J Environ Public Health, 2013, 605376 (2013).
12. Ryan, J. C., et al. Inflammatory biomarkers in CIRS. Toxicol Ind Health, 31(12), 1139–1148 (2015).
Autonomic & Vascular
13. Samsel, R. W. Microvascular regulation. Microcirculation, 18(8), 643–654 (2011).
14. Holzer, P., et al. Vasodilation/endothelial signaling. Auton Neurosci, 153(1), 15–28 (2010).