VIP
Also referenced as: Vasoactive intestinal peptide, Aviptadil, Aviptadil (pharmaceutical form), VIP 10 mg vial
A 28-amino-acid signalling peptide with vasodilatory and immunomodulatory activity, studied clinically as aviptadil and used intranasally in research contexts.
- Evidence grade
- CEarly Human Research
Early Human Research
- Regulatory status
- Investigational
Aviptadil has been investigated under trial protocols and has not been approved in the United States for the indications studied. Research-use-only VIP is not an approved medicine.
- Human data
- Limited
Registered clinical trials exist
- Last reviewed
- September 14, 2026
Overview
Vasoactive intestinal peptide is produced throughout the gut, lungs and nervous system, where it regulates smooth-muscle tone, secretion and immune signalling.
Its pharmaceutical form, aviptadil, has been trialled in acute respiratory failure and pulmonary hypertension. Separately, intranasal VIP is discussed in chronic inflammatory and mould-exposure contexts, where the published evidence is limited to small uncontrolled series.
Commonly supplied for research as a 10 mg lyophilised vial.
Why It's Being Studied
- Pulmonary surfactant production and alveolar type II cell protection.
- Immune regulation and reduction of inflammatory cytokine signalling.
- Pulmonary vascular tone and right-heart load.
- Chronic inflammatory response syndromes, where use is largely off-label and poorly evidenced.
Mechanism of Action
VIP relaxes blood vessels and airways and dampens inflammatory signalling, which is why it has been studied in lung disease.
VIP acts at VPAC1 and VPAC2 G-protein-coupled receptors, raising cAMP and activating protein kinase A. Effects include smooth-muscle relaxation, stimulation of surfactant production in alveolar type II cells, inhibition of NF-κB-driven cytokine transcription, and shifts in T-cell polarisation toward regulatory phenotypes. Plasma half-life is very short, which drives interest in infusion and intranasal delivery.
How the immune response escalates and resolves
Tap each stage to see what happens.
Background: Immune & Inflammation Research
Immune-modulating peptides are studied for their effects on T-cell maturation, cytokine signalling and inflammation control.
Some have approvals abroad for specific conditions; that does not equal broad evidence for general 'immune support'.
Research Areas & Routes Studied
- Acute respiratory failure
- Pulmonary hypertension
- Sarcoidosis
- Chronic inflammatory conditions
- Intravenous infusion (trial setting)
- Inhaled (trial setting)
- Intranasal (research)
- Subcutaneous injection (research)
Evidence Summary
The pharmaceutical form aviptadil has been studied in registered human trials for respiratory and pulmonary indications, with mixed results. Intranasal VIP as used in research settings has almost no controlled human data.
Higher tiers carry more weight. Filled tiers have evidence for VIP; tap to read it.
- Trials of intravenous and inhaled aviptadil in respiratory failure reported mixed results, with disputed effects on recovery endpoints.
- A small inhaled VIP study in pulmonary sarcoidosis reported reduced inflammatory markers in bronchoalveolar lavage.
- Registered aviptadil trials exist in respiratory failure and pulmonary hypertension.
3 cited sources.
- Randomised controlled trial1
- Clinical trial1
- Regulatory document1
Human clinical evidence
- Trials of intravenous and inhaled aviptadil in respiratory failure reported mixed results, with disputed effects on recovery endpoints.
- A small inhaled VIP study in pulmonary sarcoidosis reported reduced inflammatory markers in bronchoalveolar lavage.
Clinical trials
- Registered aviptadil trials exist in respiratory failure and pulmonary hypertension.
Preclinical evidence
- Animal and cell work supports the immunomodulatory and surfactant-related mechanisms.
Anecdotal / community information
- Intranasal VIP is discussed in patient communities for chronic inflammatory response syndrome. That use rests on clinician case series rather than controlled trials.
Reported Adverse Events in Research
- Flushing, hypotension and tachycardia are expected from vasodilation, particularly with infusion.
- Diarrhoea has been reported, consistent with the peptide's gut activity.
- Nasal irritation is reported with intranasal preparations.
Limitations of Current Evidence
- Trial results in respiratory failure have been contested and are not settled.
- Intranasal dosing regimens circulating in clinical practice are not supported by controlled trials.
- Very short half-life makes exposure hard to characterise outside infusion studies.
How to Read This Research
- Which condition was studied — infection, autoimmunity, or healthy volunteers?
- Did immune markers change, and did that translate into clinical outcomes?
- Boosting immune activity is not always beneficial; overactivity drives autoimmune disease.
- Cytokine changes in a blood test are an intermediate marker only.
- Cytokine
- A small protein that signals between immune cells.
- T-cell
- A white blood cell central to adaptive immunity.
- Immunomodulator
- Something that adjusts immune activity up or down.
Compare With Other Compounds
| VIP | Thymosin Alpha-1 | |
|---|---|---|
| Evidence grade | C — Early Human Research | B — Moderate Human Evidence |
| Regulatory status | Investigational | Clinical Trials |
| Human data | Limited | Yes |
| Clinical trials | Registered trials exist | Registered trials exist |
| Research routes | Intravenous infusion (trial setting), Inhaled (trial setting), Intranasal (research), Subcutaneous injection (research) | Subcutaneous injection |
| Cited sources | 3 | 2 |
Frequently Asked Questions
Why It Is Used
- Immune
Immune Resilience and Inflammation
Frequent infections and chronic inflammatory conditions drive interest here — and this category has more real clinical use behind it than most.
Read the case study
Research References
- Randomised controlled trial
Aviptadil in respiratory failure: randomised trial evidence
- Clinical trial
Inhaled vasoactive intestinal peptide in pulmonary sarcoidosis
- Regulatory document
Registered aviptadil and VIP trials