VIP
Endogenous signalling peptide with wide physiological roles.
What it is
Vasoactive intestinal peptide, a naturally occurring 28-amino-acid neuropeptide.
What it does
Involved in vasodilation, immune regulation, circadian signalling and smooth muscle relaxation.
Does it work?
Its physiology is well established. Therapeutic use, particularly the intranasal protocols popular in some chronic-illness communities, has much weaker controlled evidence than its biological importance might suggest.
Claims vs data
Each marketing claim, tagged by what the evidence actually supports.
| Broad, well-documented physiological roles | supported |
| Intranasal VIP treats chronic inflammatory illness | weak evidence |
Reference figures
Quoted from published reference material. These are not Peptuity recommendations.
The evidence, counted
Live counts from Europe PMC and ClinicalTrials.gov.
27,488 publications indexed, including 156 randomised controlled trials. 52 interventional studies registered. This is a well-tested compound.
query: "vasoactive intestinal peptide" · checked 2026-08-07
Most-cited literature
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Exploring the full spectrum of macrophage activation
Mosser DM, Edwards JP. · Nat Rev Immunol 2008 · 7001 citations
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Principles of interleukin (IL)-6-type cytokine signalling and its regulation
Heinrich PC, Behrmann I, Haan S, Hermanns HM, Müller-Newen G, Schaper · Biochem J 2003 · 2385 citations
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Neuroinflammation in neurodegenerative disorders: the roles of microglia and astrocytes
Kwon HS, Koh SH. · Transl Neurodegener 2020 · 2005 citations
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The blood-brain barrier: bottleneck in brain drug development
Pardridge WM. · NeuroRx 2005 · 1968 citations
Common questions
What does VIP do in normal physiology?
A great deal — vasodilation, smooth-muscle relaxation, circadian signalling and immune regulation. Its biological importance is not in question.
Why is it popular in chronic-illness communities?
Intranasal VIP protocols circulate for conditions like CIRS. The controlled evidence behind those protocols is much weaker than the enthusiasm around them.
Does biological importance imply therapeutic value?
No — and VIP is the clearest example on this site. A molecule can be essential to physiology and still lack evidence as an administered therapy.