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VIP

Last reviewed: April 18, 2026 by The Peptide Catalog Team

An immune-rebalancing peptide for CIRS, mold illness, and neuroinflammation. VIP (Vasoactive Intestinal Peptide) is a 28-amino-acid neuropeptide with broad immunomodulatory, neuroprotective, and vasodilatory effects. Central to the Shoemaker protocol for CIRS/mold illness treatment. Also researched for pulmonary hypertension, circadian rhythm regulation, and neuroinflammation.

CategoryImmune & Thymic Peptides
Classhormone analog
GoalImmune Support
Overview

Core Benefits

Key Advantages
Vasoactive immune signaling
Shifts immune response from inflammatory to regulatory.
CIRS protocol use
Central to the Shoemaker protocol for chronic CIRS.
Vasodilation effect
Cuts pulmonary artery pressure and improves blood flow.
Neuroprotection support
Protects neurons from inflammatory damage.
Nasal delivery route
Nasal spray — targets respiratory and CNS tissues directly.
Inflammatory marker drops
Reduces C4a, TGF-β1, MMP-9, and VEGF in CIRS patients.

These are educational summaries of commonly discussed effects in wellness/regenerative contexts, not guarantees.

VIP Results Timeline

Progression
1
Week 1–2
Physical Changes
Initial immune rebalancing, reduced inflammatory markers
Performance & Recovery
May notice reduced shortness of breath
Other Benefits
VCS (Visual Contrast Sensitivity) improvement beginning
2
Week 3–4
Physical Changes
C4a, TGF-β1 trending down, improved respiratory function
Performance & Recovery
Better energy, reduced brain fog
Other Benefits
CIRS symptom score improving
3
Month 2–3
Physical Changes
Significant CIRS symptom reduction, normalized markers
Performance & Recovery
Cognitive function and stamina improving substantially
Other Benefits
Pulmonary artery pressure normalizing
4
3+ Months
Physical Changes
Major quality of life improvement in CIRS patients
Performance & Recovery
Sustained immune regulation
Other Benefits
Many patients maintain on reduced frequency after initial course

Timeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.

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Evidence at a glance

Two parallel grades per outcome — clinical RCT depth and real-world community adoption. See the Research Overview below for citations and detail.

OutcomeClinical EvidenceCommunity Evidence
Pulmonary sarcoidosisModerateWeak
Pulmonary hypertension / lung inflammationWeakWeak
Erectile dysfunction (intracavernosal Invicorp)ModerateWeak
How It WorksNeuropeptide — Immunomodulator / Vasodilator

Receptor → Immune Rebalancing → Systemic Recovery → Outcomes

1
Target

VPAC1/VPAC2 Receptors (Immune Cells, Neurons, Vasculature)

VIP (Vasoactive Intestinal Peptide) activates VPAC1 and VPAC2 G-protein coupled receptors distributed widely across immune cells, neurons, pulmonary vasculature, and the GI tract. This broad receptor distribution underlies VIP's diverse effects on immunity, inflammation, and vascular function.

2
Cellular Signal

cAMP/PKA → Anti-Inflammatory + Vasodilatory Cascade

VPAC receptor activation increases intracellular cAMP, which shifts immune cells from pro-inflammatory (Th1/Th17) toward regulatory (Treg) phenotypes. In vasculature, cAMP causes smooth muscle relaxation and vasodilation. In neurons, it provides neuroprotective signaling.

3
Systemic Effect

Immune Rebalancing + Vasodilation + Neuroprotection

Shifts the immune system from inflammatory to regulatory mode — critical for CIRS (Chronic Inflammatory Response Syndrome) and mold illness. Reduces pulmonary artery pressure. Supports circadian rhythm regulation through SCN (suprachiasmatic nucleus) signaling. Protects neurons from inflammatory damage.

4
What You Notice

Reduced Inflammation → Breathing Improvement → Energy

In CIRS patients: reduced inflammatory markers (C4a, TGF-β1, MMP-9), improved breathing, and increased energy over weeks to months. Central to the Shoemaker protocol as the final step in CIRS treatment. Also used for pulmonary hypertension and neuroinflammatory conditions.

What Makes This Peptide Different

VIP is uniquely positioned at the intersection of immune, vascular, and neural systems. While Thymosin Alpha-1 enhances adaptive immunity and KPV targets inflammation, VIP rebalances the entire immune response while also addressing vascular and neurological components. The Shoemaker protocol established it as the gold-standard final treatment for CIRS/mold illness.

Research overview

Outcome-by-outcome look at what the evidence actually supports for VIP, including human vs. animal study counts and our editorial take on each.

Pulmonary sarcoidosis (inhaled VIP)

Clinical:ModerateCommunity:Weak

Prasse 2010 (open Phase 2, n=20) treated patients with histologically proven sarcoidosis with nebulized VIP for 4 weeks and showed safe, well-tolerated reduction in TNF-α production by bronchoalveolar lavage cells along with subjective cough and dyspnea improvement. This is the first human study to demonstrate VIP's immunoregulatory effect — but it is small, open-label, and a single-trial finding.

1 human study · 12 animal studies

Key findings & citations
  • Prasse 2010: TNF-α reduction in BAL cells from 20 sarcoidosis patients on inhaled VIP.
  • Subjective cough and dyspnea improvement reported.
  • Open-label, n=20 — would need a properly controlled Phase 2/3 to confirm.
  • VIP has very short systemic half-life — local pulmonary delivery is essential.

Our take

Single-trial signal in a niche indication. Community use as an injectable systemic peptide doesn't match the route of the only positive clinical study.

What VIP doesn't do

Claims that current evidence does not support. Worth knowing before you set expectations.

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Dosing ProtocolCIRS Treatment / Immune Regulation

Educational reference only. Individual responses vary. Consult healthcare provider before use.

Vial Size
5 mg
Reconstitution
5 ml BAC water
Dose
50 mcg (5 units on 1ml syringe)
Timing
AM and PM
Frequency
Every day
Duration
8 weeks on, 8 weeks off
Protocol Notes
Vasoactive intestinal peptide — used in CIRS and mold illness protocols. Can also be used intranasally. Monitor inflammatory markers during treatment.

Why This Dosing Protocol

Why nasal spray? VIP nasal spray provides direct access to nasal and pulmonary mucosa — key target tissues in CIRS. Also provides some CNS access for neuroprotective effects.

Why the Shoemaker sequence? VIP is the final step in CIRS treatment because it requires prior steps (binder therapy, MARCoNS treatment) to be completed first. Using VIP before clearing biotoxins can worsen symptoms.

Why 30-day minimum? Immune rebalancing is a gradual process. VIP needs consistent exposure over weeks to shift immune cell phenotypes from inflammatory to regulatory.
Full Dosing GuideReconstitution CalculatorCycle Cost Calculator

Reconstitution Calculator

Dilution math and unit conversions. Prefilled using a common vial size for this peptide.

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Storage & Handling

Storage at a glance

Proper storage temperatures, shelf life, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.

Powder: Freezer
1+ year at -20°C
Reconstituted: Fridge
4 weeks max at 2-8°C
View Complete Storage Guide

Handling specifics

Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.

Powder storage (very stable)
  • Freezer (-20°C): 1+ year
  • Refrigerator (2-8°C): 1-3 months
  • Room temperature: 2-3 weeks (emergency only)
Reconstituted storage (fragile)
  • MUST refrigerate at 2-8°C
  • 4-week maximum shelf life
  • NEVER freeze after reconstitution
  • Use bacteriostatic water for multi-dose
Molecular Structure

VIP sequence

Click any residue to see its properties.

HydrophobicPolarAcidic (−)Basic (+)Special

Sequence-derived properties

Length
28 residues
Molecular weight
3326.8 Da
backbone only
Avg hydrophobicity
-0.64
Kyte–Doolittle scale

Residue classes

Hydrophobic: 10 (36%)Polar: 10 (36%)Acidic (−): 2 (7%)Basic (+): 6 (21%)

Net charge distribution

Positive6 (21%)
Neutral20 (71%)
Negative2 (7%)

Amino acid frequency

K×3L×3N×3A×2D×2R×2S×2T×2V×2Y×2

Modifications

  • C-terminal amidation
  • 28-residue vasoactive intestinal peptide

Sequence and properties provided for educational reference. Not for clinical dosing decisions.

  • Length: 28 amino acids
    (Endogenous neuropeptide.)
  • Receptors: VPAC1 and VPAC2
    (G-protein coupled receptors.)
  • Administration: Intranasal
    (Nasal spray for CIRS protocol.)
  • Primary Use: CIRS / inflammation
    (Shoemaker protocol final step.)
Peptide sequence
His-Ser-Asp-Ala-Val-Phe-Thr-Asp-Asn-Tyr-Thr-Arg-Leu-Arg-Lys-Gln-Met-Ala-Val-Lys-Lys-Tyr-Leu-Asn-Ser-Ile-Leu-Asn
VIP is released by nerve terminals throughout the body. Its dual action as both a vasodilator and immunoregulator makes it uniquely effective for conditions involving chronic inflammation and immune dysregulation.
Key takeaway: VIP is the final step in the Shoemaker CIRS protocol, used after other markers are corrected. It rebalances the immune system by shifting from pro-inflammatory (Th1/Th17) to regulatory (Treg) responses, while also reducing pulmonary artery pressure.

FAQ

What is CIRS and how does VIP treat it?

CIRS (Chronic Inflammatory Response Syndrome) is a multi-system illness triggered by biotoxin exposure — most commonly from water-damaged buildings (mold). VIP is the final step in the Shoemaker protocol, used after other inflammatory markers (C4a, TGF-β1, MMP-9, VEGF) have been corrected. It rebalances the immune system from pro-inflammatory (Th1/Th17) to regulatory (Treg) responses.

Why is VIP administered as a nasal spray?

Intranasal delivery targets both the respiratory tract (relevant for CIRS lung inflammation and pulmonary hypertension) and the CNS via the olfactory pathway. It avoids first-pass liver metabolism and provides rapid local effects. The standard formulation is 50 mcg per spray, typically dosed 4 times daily.

What lab markers should be monitored during VIP therapy?

Key markers include: C4a (complement activation), TGF-β1 (fibrosis/immune dysregulation), MMP-9 (tissue remodeling), VEGF (vascular growth), MSH (melanocyte-stimulating hormone), and VIP levels themselves. Pulmonary artery pressure should also be monitored via echocardiogram. VIP should only be started after these markers are trending toward normal from earlier protocol steps.

Can VIP be used for conditions other than CIRS?

Research has explored VIP for pulmonary arterial hypertension, inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative conditions. Its role as a neuropeptide means it also regulates circadian rhythms (via the suprachiasmatic nucleus) and protects neurons from inflammatory damage. However, CIRS treatment remains its most established clinical application.

What are the side effects of VIP?

VIP is generally well-tolerated at therapeutic doses. Some patients report mild nasal irritation, transient flushing, or loose stools (VIP stimulates intestinal secretion — it's called "vasoactive intestinal peptide" for a reason). Rarely, excessive doses can cause hypotension due to vasodilation. Monitoring by a CIRS-literate physician is recommended.

How long does reconstituted peptide last?

Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.

Is this peptide legal to purchase?

Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.

New to peptides?

Take our Peptide Match tool to find the best peptide for your goals. You can also read our Complete Guide to Peptides to learn the basics.

VIP Research Articles

guides

VIP Dosage Chart: 50mcg SubQ AM/PM Protocol

VIP is the final step in the Shoemaker protocol — using it too early backfires. Covers 50mcg SubQ, intranasal CIRS dosing, and cycling.

reconstitution

VIP Reconstitution: 5mg + 5mL Chart

50mcg = 5 units at 1mg/mL. The mix differs for SubQ vs intranasal — dilution charts, syringe math, and nasal-spray prep, step by step.

side-effects

VIP Side Effects: 7 to Watch For

Transient hypotension hits most VIP users — but lipase elevation is the one to actually monitor. Full safety breakdown by frequency.

guides

Buy VIP: Compare 4 Vendors, From $58

Compare 4 VIP vendors side by side: from $58 a vial, best value $5.80/mg. Codes save up to 50%. Vial sizes, COA status, real cost per week.

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Disclosure: we may earn affiliate commission from qualifying purchases. Educational information only — not medical advice.