Fact-checked by the Peptide Authority Editorial Board · Last reviewed: 2026-02-01
What Is VIP? Benefits, Research & Safety
A neuropeptide with vasodilatory, anti-inflammatory, and immunomodulatory properties, researched for various therapeutic applications.
Also known as:
Vasoactive Intestinal Peptide
Vasoactive Intestinal Polypeptide
Educational Content Only: This page provides research-based information for educational purposes. VIP is not an approved medicine. This is not medical advice. Always consult a qualified healthcare professional.
Quick Facts
Category
Immune & Inflammatory
Half-Life
Very short; approximately 1-2 minutes in plasma
UK Status
Not licensed for general use. May be available in research settings.
EU Status
Not approved for standard therapeutic use.
Overview
Vasoactive Intestinal Peptide (VIP) is a 28-amino acid neuropeptide belonging to the secretin-glucagon family. First isolated from porcine intestine in 1970, VIP is now known to be widely distributed throughout the body, functioning as both a neurotransmitter and an endocrine hormone.
VIP exerts diverse physiological effects including vasodilation, smooth muscle relaxation, secretion regulation, immunomodulation, and neuroprotection. It plays important roles in the gastrointestinal, cardiovascular, respiratory, and nervous systems.
Research has explored VIP's therapeutic potential in numerous conditions including pulmonary hypertension, inflammatory bowel disease, sepsis, and neurodegenerative diseases. Its potent anti-inflammatory and immunomodulatory effects have attracted particular interest.
Aviptadil, a synthetic VIP, has been investigated for various conditions. It received FDA Emergency Use Authorization for COVID-19-related respiratory failure in 2020, though results have been mixed. Clinical development continues for pulmonary conditions.
VIP's short half-life and broad biological activities present challenges for therapeutic development. Research continues into delivery systems and VIP-based therapeutics with improved pharmacokinetic properties.
Discovery & History
VIP was discovered by Sami Said and Viktor Mutt in 1970, isolated from porcine small intestine. It was initially characterised by its potent vasodilatory properties, hence the name "vasoactive intestinal peptide."
Early research focused on VIP's gastrointestinal effects, including stimulation of secretion, relaxation of smooth muscle, and regulation of blood flow. Its wide distribution throughout the nervous system was subsequently recognised.
In the 1990s and 2000s, research expanded to VIP's immunomodulatory properties. Studies demonstrated potent anti-inflammatory effects and potential in autoimmune disease models. This opened new therapeutic avenues.
VIP's role in the lungs became increasingly appreciated, with evidence for vasodilatory and bronchodilatory effects. Research explored VIP for pulmonary hypertension and ARDS (acute respiratory distress syndrome).
During the COVID-19 pandemic, aviptadil (synthetic VIP) was rapidly investigated for COVID-19-related respiratory failure, receiving Emergency Use Authorization. While results were mixed, this highlighted ongoing interest in VIP therapeutics.
Current research explores improved formulations, delivery systems (such as nasal administration), and VIP analogues with better stability and selectivity.
Mechanism of Action
VIP acts through specific G protein-coupled receptors with diverse downstream effects:
**Receptor Activation**
VIP binds to two main receptors:
- VPAC1: Widely distributed; predominant in immune cells, brain, and liver
- VPAC2: Expressed in smooth muscle, gastrointestinal tract, and immune cells
- Both couple to Gs proteins, increasing cAMP
**Vasodilation**
VIP causes potent relaxation of blood vessels:
- Increases cAMP in vascular smooth muscle
- Stimulates nitric oxide release
- Results in vasodilation and reduced blood pressure
- Effects in pulmonary and systemic circulation
**Anti-Inflammatory and Immunomodulatory Effects**
Key therapeutic interest:
- Inhibits pro-inflammatory cytokine production (TNF-α, IL-6, etc.)
- Promotes regulatory T cell function
- Shifts immune responses from Th1/Th17 toward Th2
- Inhibits macrophage and dendritic cell activation
**Bronchodilation and Lung Protection**
Effects in the respiratory system:
- Relaxation of airway smooth muscle
- Protection against lung injury
- Potential surfactant secretion enhancement
- Anti-inflammatory effects in airways
**Neuroprotection**
CNS effects include:
- Protection against excitotoxicity
- Anti-apoptotic effects on neurons
- Regulation of circadian rhythms
- Involvement in memory and learning
[Molecular Structure Diagram Placeholder]
Researched Benefits
Based on preclinical and clinical research findings:
- 1Potent vasodilation, particularly in pulmonary circulation
- 2Anti-inflammatory effects in various models
- 3Bronchodilation and airway protection
- 4Immunomodulation in autoimmune disease research
- 5Neuroprotective properties
- 6Potential in ARDS and respiratory failure (under investigation)
Theoretical Dosing & Protocols
⚠️ Educational Only: The following information is derived from research literature and is not a prescription or recommendation. No standardised human dosing exists. Always consult a qualified healthcare professional.
| Theoretical Dosage | Variable depending on indication and delivery method |
| Frequency | Variable |
| Duration | Variable |
| Notes | VIP/aviptadil is under clinical investigation for various conditions. It is not widely approved for therapeutic use. Short half-life requires consideration of delivery method. Research and clinical use should be under specialist supervision. |
Administration Routes
Routes studied in research settings (educational only):
- Intravenous (clinical trials)
- Inhaled (pulmonary applications)
- Intranasal (some research)
| Half-Life | Stability |
|---|---|
| Very short; approximately 1-2 minutes in plasma | Requires careful handling; subject to enzymatic degradation |
Safety Profile & Known Risks
Commonly Reported Side Effects
- Hypotension (due to vasodilation)
- Flushing
- Tachycardia
- Gastrointestinal effects
- Headache
Rare Risks & Concerns
- Severe hypotension
- Cardiac arrhythmias
- Unknown long-term effects
Contraindications
- Hypotension
- Cardiogenic shock
- Certain cardiac conditions
- Pregnancy (limited data)
UK & EU Regulatory Context
🇬🇧 United Kingdom
Not licensed for general use. May be available in research settings.
🇪🇺 European Union
Not approved for standard therapeutic use.
VIP (aviptadil) has been granted Emergency Use Authorization in some jurisdictions for specific indications. It is not widely approved. Clinical trials continue for pulmonary hypertension, ARDS, and other conditions.
Clinical Studies Summary
VIP for COVID-19 Respiratory Failure
Clinical trials evaluating inhaled aviptadil for COVID-19-related respiratory failure.
Critical care and pulmonary journalsView on PubMed
VIP in Pulmonary Arterial Hypertension
Research investigating VIP for pulmonary hypertension treatment.
Pulmonary and cardiovascular journalsView on PubMed
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