WhatPeptide

VIP

Vasoactive Intestinal Peptide (VIP) is an endogenous 28-amino acid neuropeptide with potent anti-inflammatory, vasodilatory, and immunomodulatory properties, studied most notably in the context of Chronic Inflammatory Response Syndrome (CIRS) and pulmonary arterial hypertension. Intranasal delivery targets pulmonary and systemic anti-inflammatory pathways.

Preliminary evidence Unregulated Immune

Written by WhatPeptide Editorial Team · Last updated 2026-03-17

Half-life

Approximately 1-2 minutes in plasma; local intranasal effects prolonged

Dosage range

50 mcg intranasally 4x daily (Shoemaker CIRS protocol)

Administration

Intranasal

Research level

Preliminary

How VIP works

VIP binds VPAC1 and VPAC2 receptors expressed on immune cells, airway epithelium, and vascular smooth muscle, activating cAMP/PKA pathways that suppress pro-inflammatory cytokine production (TNF-alpha, IL-6, IL-12) while promoting IL-10 and regulatory T cell activity. In CIRS protocols, VIP is proposed to correct dysregulated innate immune signaling associated with biotoxin exposure. Pulmonary VIP deficiency has been documented in pulmonary arterial hypertension, providing a mechanistic rationale for inhaled replacement therapy.

Also known as: Vasoactive Intestinal Peptide, VIP neuropeptide

Research relevance

Immune Support
Moderate relevance 55
Gut Health
Moderate relevance 50

Side effects & safety

Facial flushing Nausea Headache Hypotension Nasal irritation

Contraindications

Hypotension
Pregnancy
Should be used within established CIRS protocols under physician supervision

Consult a healthcare provider before use if any of these apply to you.

Key studies

FAQ

What is VIP? +
Vasoactive Intestinal Peptide (VIP) is an endogenous 28-amino acid neuropeptide with potent anti-inflammatory, vasodilatory, and immunomodulatory properties, studied most notably in the context of Chronic Inflammatory Response Syndrome (CIRS) and pulmonary arterial hypertension. Intranasal delivery targets pulmonary and systemic anti-inflammatory pathways. Its mechanism of action is based on preliminary or early-stage research.
What is VIP researched for? +
VIP has the strongest research relevance for Immune Support, Gut Health. Evidence is based on preliminary or early-stage research.
What are the side effects of VIP? +
Reported side effects include Facial flushing, Nausea, Headache, Hypotension, Nasal irritation. Key contraindications: Hypotension; Pregnancy; Should be used within established CIRS protocols under physician supervision.
Is VIP FDA approved? +
VIP is not FDA-approved. It is available as a research compound or through compounding pharmacies in some jurisdictions.
How is VIP administered? +
VIP is typically administered via nasal route. Researched dosage range: 50 mcg intranasally 4x daily (Shoemaker CIRS protocol). Half-life: Approximately 1-2 minutes in plasma; local intranasal effects prolonged.

Explore similar peptides

Thymalin

Moderate evidence

Immune

Thymalin is a thymic peptide preparation studied for immune system restoration and modulation, particularly in aging-related immune decline (immunosenescence) and post-illness immune reconstitution. It has been investigated in longitudinal anti-aging studies in Eastern European research literature with reported improvements in immune biomarkers.

Thymosin Alpha-1

Moderate evidence

Immune

An immunomodulatory peptide approved in over 35 countries (as Zadaxin) for hepatitis B/C and as an immune adjunct. Not FDA-approved in the US. Was placed on FDA Category 2 list (September 2023 – September 2024) before being removed when the nominator withdrew. Current regulatory status is in flux; FDA continues to flag safety concerns.

Vilon

Preliminary evidence

Immune

Vilon is a synthetic dipeptide (Lys-Glu) derived from the thymus gland, studied as an immune-regulatory bioregulator that promotes thymic function restoration and has been investigated in the same anti-aging peptide bioregulator research tradition as Epithalon and Thymalin. It represents one of the shortest bioactive peptides studied for immune modulation.