VIP (Vasoactive Intestinal Peptide)
Endogenous 28-amino-acid neuropeptide with broad anti-inflammatory and immunomodulatory roles.
At a glance
What it is: Endogenous 28-amino-acid neuropeptide with broad anti-inflammatory and immunomodulatory roles..
Primary research applications:
- Inflammation and immunoregulation research
- Pulmonary hypertension and sarcoidosis trials
- Chronic inflammatory illness research interest
Editorial summary: VIP is a well-characterized endogenous neuropeptide with a broad anti-inflammatory profile in basic science. Its translational story is mixed — early respiratory disease trials yielded modest signals — and recent interest in chronic inflammatory illness communities has outpaced the controlled human evidence.
- Class / structure
- 28-amino-acid neuropeptide (secretin family)
- Half-life
- Very short — minutes in plasma
- First described
- 1970 (Said and Mutt)
- Regulatory status
- Not FDA-approved; investigational analogs in development
What is VIP?
VIP is a 28-amino-acid neuropeptide produced by neurons throughout the central and peripheral nervous systems and by enteric and immune cells. It binds VPAC1 and VPAC2 receptors, both G-protein-coupled receptors with broad tissue distribution.
Discovery and development
VIP was first isolated from porcine intestine by Sami Said and Viktor Mutt in 1970. Its initial characterization as a vasodilator gave it its name; subsequent decades of research established its broad role as a neuropeptide signaling across the immune, nervous, and respiratory systems. VIP is structurally related to PACAP and the secretin / glucagon family of peptides.
Mechanism of action
VIP has anti-inflammatory effects on multiple immune cell types — reducing pro-inflammatory cytokine production, modulating T-cell differentiation toward regulatory phenotypes, and dampening macrophage activation. Its receptors are expressed in airway smooth muscle, immune cells, neurons, and gastrointestinal tissue.[1]
Pharmacokinetics
VIP has a notably short plasma half-life (a few minutes), reflecting its biology as a paracrine and neurocrine signaling molecule rather than a circulating hormone. Therapeutic strategies have focused on aerosol delivery (for pulmonary indications), engineered analogs with extended half-life, and receptor-selective agonists.
What the research shows
The peer-reviewed literature on VIP is summarized below across two tiers: human research (the highest standard), and preclinical / emerging research (animal models and early-stage human work).
Claims and the evidence behind them
This table summarizes commonly discussed claims and how the published evidence weighs in. The aim is clarity — supported claims, claims that look promising but need more data, and claims that outrun the science.
| Claim | What the evidence shows | Verdict |
|---|---|---|
| Has anti-inflammatory effects in animal models | Extensive literature | Supported |
| Treats CIRS / mold illness | No controlled human trials in that population | Uncertain |
| Improves chronic inflammatory disease in humans | Some signals; no Phase 3 efficacy | Uncertain |
Reported user experiences
How the research describes administration
Most published research used inhaled or intravenous VIP. Compounded intranasal VIP is sometimes used in chronic-illness communities; this is off-label and outside formal clinical trials.
Editorial note
Administration details above describe how the peptide is given in published studies. We summarize this for educational completeness — these descriptions are not protocols, dosing recommendations, or instructions for personal use. Decisions about treatment require an appropriately licensed clinician.
Safety considerations and open questions
The takeaway
VIP is a foundational neuropeptide of human physiology with a credible anti-inflammatory mechanism and a long history of translational interest. Its current clinical role is limited and its use in chronic-illness communities deserves careful interpretation — meaningful biology, but the controlled trial evidence in the populations where it is most discussed is largely absent.
Frequently asked questions
Is VIP FDA-approved?
No. VIP itself is not approved for any indication. Compounded intranasal VIP is sometimes used in CIRS / mold-illness clinical contexts under the supervision of practitioners.
How does VIP relate to PACAP?
VIP and PACAP are structurally related and share receptors (VPAC1 and VPAC2; PACAP also has its own PAC1 receptor). Both are anti-inflammatory neuropeptides with overlapping biology.
References
- Delgado M, Pozo D, Ganea D. The significance of vasoactive intestinal peptide in immunomodulation. Pharmacol Rev. 2004;56(2):249-290. https://pubmed.ncbi.nlm.nih.gov/15169929/
- Petkov V, et al. Vasoactive intestinal peptide as a new drug for treatment of primary pulmonary hypertension. J Clin Invest. 2003;111(9):1339-1346. https://pubmed.ncbi.nlm.nih.gov/12727925/