VIP
28-amino-acid neuropeptide with vasodilatory, anti-inflammatory, and immunomodulatory activity
- Class
- Neuropeptide
- Half-life
- ~1–2 min
- Route
- Intranasal
- Cadence
- Daily
- Evidence
- Mixed / early human
Overview
VIP is an endogenous 28-amino-acid neuropeptide made in your gut, brain, and lungs. It does several things — relaxes smooth muscle (including airways and blood vessels), drives anti-inflammatory signalling, and helps regulate your circadian rhythm through receptors in the suprachiasmatic nucleus. The synthetic version, aviptadil, was tested in COVID-19 ARDS trials and has FDA Fast Track designation, but it's not approved for routine use anywhere.
The core mechanism is binding to VPAC1 and VPAC2 receptors, which triggers cAMP production and blocks NF-κB translocation — the latter is how it suppresses inflammatory cytokines like TNF-α and IL-6. In the lung, 70% of VIP binds to VPAC1 receptors on alveolar type-II cells, where it protects against lung injury and maintains surfactant production. It's also been tested (with mixed results) in sarcoidosis, pulmonary hypertension, inflammatory bowel disease, and as part of CIRS (mould illness) protocols, though evidence quality varies widely by indication.
The catch: VIP's plasma half-life is about 1–2 minutes. It's chewed up by DPP-IV and neutral endopeptidase before it can reach most tissues systemically. This means IV or inhaled formulations cause dose-limiting hypotension and flushing, and intranasal delivery is the most practical route for non-pulmonary uses — but even that hasn't been validated in large controlled trials. The research-market peptide is unregulated, and purity varies.
Safety considerations
A few of the safety signals worth knowing — the full list, with dosing context and what to monitor, is inside AIx Core.
- Not approved for human use outside clinical trials — research-market VIP is unregulated and sold for laboratory purposes only.
- Dose-limiting hypotension and tachycardia are the dominant safety concerns with IV administration. Slow infusion and dose-titration are mandatory in clinical protocols.
- Flushing, diarrhoea, and lightheadedness are common vasodilatory effects — usually mild with intranasal dosing, more pronounced with IV.
+ 3 more safety notes inside AIx Core →
Commonly monitored
Markers and signals people track when researching VIP.
- Blood pressure (systemic vasodilation is the dose-limiting side effect)
- Heart rate (can increase transiently)
- Respiratory parameters if using for lung conditions (oxygenation, P/F ratio)
- IL-6 and inflammatory markers if using for autoimmune/inflammatory conditions
- Subjective: flushing, lightheadedness, diarrhoea (common with IV/high doses)
Frequently asked questions
What is VIP?
28-amino-acid neuropeptide with vasodilatory, anti-inflammatory, and immunomodulatory activity. VIP is an endogenous 28-amino-acid neuropeptide made in your gut, brain, and lungs. It does several things — relaxes smooth muscle (including airways and blood vessels), drives anti-inflammatory signalling, and helps regulate your circadian rhythm through receptors in the suprachiasmatic nucleus. The synthetic version, aviptadil, was tested in COVID-19 ARDS trials and has FDA Fast Track designation, but it's not approved for routine use anywhere.
How is VIP administered?
Intranasal, typically daily.
What is the half-life of VIP?
~1–2 min — Extremely short plasma half-life — most peptide degraded by DPP-IV within minutes of systemic exposure.
Is VIP approved for human use?
VIP is investigational — not approved by the FDA, EMA, or MHRA for human use at the time of writing.
What does the evidence show for VIP?
Evidence tier: Mixed / early human. Youssef et al. 2021 (N=196, RCT): aviptadil 3-day IV infusion in COVID-19 respiratory failure showed patients were more likely to be alive and free from respiratory failure at 60 days (P=.02 controlling for baseline severity), but a later ACTIV-3b trial by Brown et al. showed no significant improvement in 90-day survival.
What is commonly monitored when researching VIP?
Commonly tracked markers + signals: Blood pressure (systemic vasodilation is the dose-limiting side effect), Heart rate (can increase transiently), Respiratory parameters if using for lung conditions (oxygenation, P/F ratio), IL-6 and inflammatory markers if using for autoimmune/inflammatory conditions, Subjective: flushing, lightheadedness, diarrhoea (common with IV/high doses).
Related compounds
Open this in AIx Core for the full picture
Mechanism breakdown, receptor pathway diagram, full safety list, monitored items, source citations, and one-tap add-to-protocol. Free with any account.