VIP
A natural peptide found throughout the body, especially in the nervous system, gut, and lungs. It widens blood vessels, calms inflammation, and helps balance the immune system. Most studied for chronic inflammatory conditions (like mold illness) and high blood pressure in the lungs, where it tones down excessive inflammatory signaling. People use it for CIRS, mold illness, and similar conditions.
Dosage
Intranasal: 50 mcg per spray 1-4x daily. Subcutaneous: 50-100 mcg daily
Dosages shown are for research reference only. Always consult a qualified healthcare provider.
Administration
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Effects
Vasodilation
Among the most potent vasodilators in the body — relaxes vascular smooth muscle.
Immune Balancing
Shifts from Th1 pro-inflammatory to balanced Th2/Treg response — key for CIRS.
Neuroprotection
Upregulates BDNF, supports circadian regulation in the suprachiasmatic nucleus.
Mechanism of Action
Vasoactive Intestinal Peptide is a 28-amino-acid neuropeptide that belongs to the secretin/glucagon superfamily. It is widely distributed throughout the body — found in neurons of the central and peripheral nervous systems, immune cells, and the gastrointestinal tract — and acts through two G protein-coupled receptors: VPAC1 (expressed broadly) and VPAC2 (more restricted to CNS and immune tissue). Both receptors couple to Gs proteins, activating adenylyl cyclase and raising intracellular cAMP.
VIP's vasodilatory effect is among the most potent in the body. It relaxes vascular, airway, and gastrointestinal smooth muscle by activating cAMP/PKA signaling, which phosphorylates myosin light chain kinase and reduces calcium sensitivity in smooth muscle cells. In the pulmonary vasculature, this produces bronchodilation and reduced pulmonary artery pressure. In cerebral vasculature, VIP is a key regulator of blood flow.
The immunomodulatory effects are particularly relevant for its use in chronic inflammatory response syndrome (CIRS). VIP powerfully suppresses the Th1 (pro-inflammatory) immune response while promoting Th2 and regulatory T cell (Treg) differentiation. It inhibits macrophage production of TNF-α, IL-6, IL-12, and nitric oxide, and suppresses dendritic cell maturation and antigen presentation. This immune-balancing effect makes VIP valuable in conditions characterized by chronic Th1/Th17 immune dysregulation, such as mold illness/CIRS. In the brain, VIP is neuroprotective — it upregulates BDNF and activity-dependent neuroprotective protein (ADNP), supports circadian rhythm regulation in the suprachiasmatic nucleus, and protects neurons from inflammatory and oxidative damage. The extremely short plasma half-life (1-2 minutes) necessitates intranasal delivery for CNS effects, bypassing the blood-brain barrier through olfactory and trigeminal nerve transport.
Regulatory Status
Not FDA approved for CIRS/mold illness. FDA approved as a diagnostic agent (VIP stimulation test). Available through compounding pharmacies for off-label use.
Risks & Safety
Common
diarrhea, widened blood vessels and facial flushing, nasal congestion when used as a nasal spray, mild low blood pressure.
Serious
significant drop in blood pressure in sensitive people or at high doses; fast heart rate from the body's response to widened blood vessels.
Rare
severe allergic reactions, airway narrowing. Very short half-life naturally limits how much reaches the rest of the body.
Compare VIP With
Research Papers
32Published: January 27, 2026
AI Summary
Calcium-binding proteins alone cannot reliably classify GABAergic neurons in macaque visual cortex, since many labeled cells are not GABAergic. Using VIP and somatostatin alongside parvalbumin provides a more accurate scheme for identifying inhibitory neuron types.
Published: February 28, 2026
AI Summary
Atractylodes dietary fiber relieved constipation in rats by raising gut hormones like VIP and substance P, improving gut bacteria, and reducing inflammation. The fiber may offer a natural approach to functional constipation.
Published: January 31, 2026
AI Summary
Abstract too short to summarize.
Published: January 29, 2026
AI Summary
Abstract too short to summarize.
Published: January 22, 2026
AI Summary
Bifidobacterium breve and Lacto-N-neotetraose together relieved constipation in mice by increasing gut acetate, improving transit and mucus, and lowering VIP and nitric oxide. The effect depended on gut bacteria and their metabolites.
Published: January 24, 2026
AI Summary
VIP neurons in the dorsal raphe regulate sleep and defensive behavior by connecting to threat-processing brain regions. Removing these neurons disrupted sleep and threat responses, suggesting they act as an alarm system for survival.
Published: January 19, 2026
AI Summary
Neuron-derived VIP controls gut lining cell differentiation and immune balance through VIPR1, and helps maintain gut barrier function. The findings reveal a neuro-epithelial circuit that shapes gut immunity and barrier integrity.
Published: January 4, 2025
AI Summary
Abstract too short to summarize.
Published: January 20, 2026
AI Summary
Imaging and fluid biomarkers can help predict outcomes in cerebral amyloid angiopathy, including hemorrhage and cognitive decline. Combining MRI, PET, and blood markers may enable more personalized prognosis and care.
Published: February 28, 2026
AI Summary
SPP1 promoted radiotherapy resistance in cervical cancer by driving CCL2 and M2-like macrophage polarization. Blocking SPP1 reduced tumor growth and may improve responses to radiation and immunotherapy.
Published: February 7, 2026
AI Summary
Abstract too short to summarize.
Published: February 11, 2026
AI Summary
Glyphosate, AMPA, and oxytetracycline damaged the gut-liver axis in zebrafish, with combined exposure causing worse effects. The findings highlight overlooked risks from herbicides and antibiotics in aquatic environments.
Published: January 26, 2026
AI Summary
VIP, parvalbumin, and somatostatin interneurons each shaped noise correlations and orientation discrimination in mouse visual cortex differently. The results clarify how inhibitory circuits influence sensory perception.
Published: January 14, 2026
AI Summary
An automated culture system showed that VIP pulses rapidly reset circadian rhythms by synchronizing PER2 protein levels. The tool may advance research on circadian disorders and how the brain clock stays in sync.
Published: January 13, 2026
AI Summary
Ancient gut microbiomes from fossilized feces yielded antimicrobial peptides, many from Segatella copri, a bacterium now rare in Western populations. Some peptides showed strong antibacterial and wound-healing effects in vivo.
Published: January 12, 2026
AI Summary
Exosomes loaded with an IKVAV peptide promoted spinal cord repair in mice by first reducing inflammation and then supporting nerve regeneration. The dual-action approach improved motor recovery after injury.
Published: January 31, 2026
AI Summary
VIP and secretin activated phosphatases PP1 and PP2A in pancreatic cells through different pathways, and both were needed for fluid and electrolyte secretion. The work clarifies how gut hormones drive pancreatic secretion.
Published: January 9, 2026
AI Summary
Combining cyclosporine A with a flavone derivative triggered pyroptosis in liver cancer cells via RIG-I-like receptor signaling and LDHA inhibition. The combination reduced tumor growth and metastasis in mice.
Published: December 22, 2025
AI Summary
Chronic restraint stress in mice reduced markers of synapses, VIP and other interneurons, and astrocytes in the prefrontal cortex, with anxiety appearing before anhedonia. Male and female mice showed different molecular changes.
Published: February 2, 2026
AI Summary
TMAO produced in the uterine lining supported decidualization and reduced pregnancy loss in mice; low TMAO was linked to recurrent miscarriage. Restoring TMAO improved decidualization in some patient-derived cells.
Published: January 8, 2026
AI Summary
Abstract too short to summarize.
Published: November 8, 2025
AI Summary
Ganoderma lucidum spores improved spleen deficiency in mice by modulating gut hormones including VIP and somatostatin, boosting energy metabolism and immunity. The spores showed spleen-strengthening effects in this model.
Published: September 8, 2025
AI Summary
A network meta-analysis ranked Chinese medicine injections combined with conventional therapy for heart failure; Shuxuetong and Shenmai were among the top options for several outcomes. More high-quality trials are needed to confirm results.
Published: January 25, 2026
AI Summary
Abstract too short to summarize.
Published: January 6, 2026
AI Summary
IGF1-positive macrophages were linked to relapse in eosinophilic granulomatosis with polyangiitis, and blocking IGF1 reduced type 2 inflammation in animal models. IGF1 may be a therapeutic target in this condition.
Published: December 31, 2025
AI Summary
Elevated VIP levels were poorly predictive of VIPoma; most patients with high VIP did not have the tumor. VIP testing is best reserved for chronic diarrhea in specific clinical settings, with a threshold around 442 pg/mL offering better accuracy.
Published: December 25, 2025
AI Summary
Alcohol withdrawal changed the activity of parvalbumin, somatostatin, and VIP interneurons in the prelimbic cortex, with different effects in males and females. The findings may inform treatments for withdrawal and negative affect in alcohol use disorder.
Published: January 4, 2026
AI Summary
VIP amplifies and phase-delays vasopressin neuron rhythms in the brain's clock, and a feedback loop between these neurons is needed for stable 24-hour rhythms. VIP deficiency shortened the circadian period in mice.
Published: January 4, 2026
AI Summary
Abstract too short to summarize.
Published: January 26, 2026
AI Summary
Adult-onset blindness rapidly rewired spontaneous activity in visual cortex, with pyramidal and VIP neuron networks restructuring quickly while somatostatin networks stayed stable. The changes reflect fast adaptation to vision loss.
Published: February 11, 2026
AI Summary
Merkel cells in the vagina may have mechanosensory roles similar to those in skin, but their function there is still unclear. The study aimed to characterize these cells and their potential roles.
Published: February 11, 2026
AI Summary
Only a small subset of VIP neurons in the brain's clock region responds to vasopressin, and this response helps maintain robust daily rhythms. The work maps how different neuron types communicate within the circadian clock.
Frequently Asked Questions
What is VIP?
A natural peptide found throughout the body, especially in the nervous system, gut, and lungs. It widens blood vessels, calms inflammation, and helps balance the immune system. Most studied for chronic inflammatory conditions (like mold illness) and high blood pressure in the lungs, where it tones down excessive inflammatory signaling. People use it for CIRS, mold illness, and similar conditions.
What is VIP used for?
A natural peptide found throughout the body, especially in the nervous system, gut, and lungs. It widens blood vessels, calms inflammation, and helps balance the immune system. Most studied for chronic inflammatory conditions (like mold illness) and high blood pressure in the lungs, where it tones down excessive inflammatory signaling. People use it for CIRS, mold illness, and similar conditions.
What is the dosage for VIP?
Intranasal (preferred): 50 mcg per spray, one to four times daily. Subcutaneous: 50-100 mcg once daily. CIRS protocol (Shoemaker): intranasal delivery for brain and sinus access. Treatment duration varies by condition.
What are the side effects of VIP?
Common: diarrhea, widened blood vessels and facial flushing, nasal congestion when used as a nasal spray, mild low blood pressure. Serious: significant drop in blood pressure in sensitive people or at high doses; fast heart rate from the body's response to widened blood vessels. Rare: severe allergic reactions, airway narrowing. Very short half-life naturally limits how much reaches the rest of the body.
How does VIP work?
Vasoactive Intestinal Peptide is a 28-amino-acid neuropeptide that belongs to the secretin/glucagon superfamily. It is widely distributed throughout the body — found in neurons of the central and peripheral nervous systems, immune cells, and the gastrointestinal tract — and acts through two G protein-coupled receptors: VPAC1 (expressed broadly) and VPAC2 (more restricted to CNS and immune tissue). Both receptors couple to Gs proteins, activating adenylyl cyclase and raising intracellular cAMP. VIP's vasodilatory effect is among the most potent in the body. It relaxes vascular, airway, and gastrointestinal smooth muscle by activating cAMP/PKA signaling, which phosphorylates myosin light chain kinase and reduces calcium sensitivity in smooth muscle cells. In the pulmonary vasculature, this produces bronchodilation and reduced pulmonary artery pressure. In cerebral vasculature, VIP is a key regulator of blood flow. The immunomodulatory effects are particularly relevant for its use in chronic inflammatory response syndrome (CIRS). VIP powerfully suppresses the Th1 (pro-inflammatory) immune response while promoting Th2 and regulatory T cell (Treg) differentiation. It inhibits macrophage production of TNF-α, IL-6, IL-12, and nitric oxide, and suppresses dendritic cell maturation and antigen presentation. This immune-balancing effect makes VIP valuable in conditions characterized by chronic Th1/Th17 immune dysregulation, such as mold illness/CIRS. In the brain, VIP is neuroprotective — it upregulates BDNF and activity-dependent neuroprotective protein (ADNP), supports circadian rhythm regulation in the suprachiasmatic nucleus, and protects neurons from inflammatory and oxidative damage. The extremely short plasma half-life (1-2 minutes) necessitates intranasal delivery for CNS effects, bypassing the blood-brain barrier through olfactory and trigeminal nerve transport.
How is VIP administered?
VIP is administered via intranasal spray or subcutaneous injection.
What is the half-life of VIP?
The half-life of VIP is 1-2 minutes (rapidly degraded by peptidases).
Is VIP legal?
Not FDA approved for CIRS/mold illness. FDA approved as a diagnostic agent (VIP stimulation test). Available through compounding pharmacies for off-label use.
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