Vasoactive Intestinal Peptide

What is Vasoactive Intestinal Peptide?

A 28-amino-acid neuropeptide that functions as a neurotransmitter and neuromodulator. Modulates inflammatory responses, immune function, and gastrointestinal secretion. Found naturally in the nervous and immune systems.

How it works

VIP activates GPCRs (VPAC1/VPAC2) on epithelial and immune cells, triggering cAMP signaling. This pathway suppresses pro-inflammatory cytokine production and enhances barrier function.

Background & history

Discovered in 1970 as a vasoactive hormone in intestinal tissue. Initially characterized for vasodilation; immune-regulatory roles were identified in the 1990s.

What the research says

Animal and limited human studies suggest VIP may reduce inflammatory markers and support immune tolerance. Research indicates potential benefits for gut barrier function and inflammatory conditions, but human clinical evidence remains sparse. Most data derives from preclinical models and small observational studies. Long-term safety in humans is not well-established.

Reported effects

• Studied for immune-modulation and anti-inflammatory signaling
• Reported to support gastrointestinal barrier integrity
• Researched for neuroimmune regulation
• Preliminary evidence for neuroprotective properties
• Limited human data; mostly animal and laboratory studies

Dosing & administration (informational)

Safety & side effects

• Not approved for human injection; significant contamination and sterility risk if not pharmaceutical-grade
• Potential cardiovascular effects; contraindicated in some conditions
• Limited human safety data; unknown adverse event profile at typical dosages
• Risk of endotoxin contamination from non-GMP synthesis
• Possible immune activation or sensitization with repeated exposure

Drug & supplement interactions

• May potentiate effects of other immunomodulators
• Cardiovascular effects may interact with antihypertensive agents
• Possible sensitization with repeated immune-activating compounds
• Interaction with cholinergic or adrenergic agents uncertain

Who should avoid it

• Concurrent immunosuppressive therapies without medical oversight
• Administration in advanced cardiovascular disease
• Non-pharmaceutical or non-sterile sources
• Repeated dosing without safety monitoring

How it is commonly combined

Combining VIP with other neuroimmune peptides (thymulin, thymosin) is theoretical; no human safety data exist.

Quality & harm reduction

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Frequently asked questions

References & further reading

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