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Vasoactive Intestinal Peptide, commonly abbreviated VIP, is a 28-amino-acid neuropeptide studied across gastrointestinal, pulmonary, vascular, immune, circadian and central nervous system research. VIP interacts mainly with VPAC1 and VPAC2 receptors, with additional relevance to PACAP-related receptor biology. This 2026 guide explains VIP structure, receptor signaling, tissue distribution, research areas, evidence limitations, comparison to related peptides and research-use-only quality standards.
VIP, or Vasoactive Intestinal Peptide, is a 28-amino-acid neuropeptide studied for VPAC1 and VPAC2 receptor signaling, cAMP pathway activation, smooth-muscle relaxation, vasoregulatory signaling, immune modulation, gastrointestinal homeostasis, pulmonary biology and brain-gut communication. In research terms, VIP is best understood as a pleiotropic neuroimmune and regulatory peptide, not as a single-purpose compound or a consumer-use product.
Vasoactive Intestinal Peptide is a naturally occurring neuropeptide first identified for vasodilatory activity, but later research expanded its importance across multiple biological systems. VIP is expressed in the central and peripheral nervous systems, gastrointestinal tract, respiratory tract and immune-related tissues.
VIP is a small signaling peptide used by the body in many tissues. Researchers study it because it can influence receptor pathways involved in smooth muscle, blood vessels, immune signaling, gut function, lung biology and nervous-system communication.
The broad activity of VIP is both scientifically valuable and difficult to interpret. Its effects depend on receptor subtype, tissue type, experimental model, concentration, exposure time and local biological environment.
VIP is a 28-amino-acid peptide hormone and neuropeptide belonging to the glucagon-secretin peptide family. It is highly conserved across species and is studied as a regulator of cAMP-linked signaling in multiple tissue systems.
| Feature | VIP Detail | Research Interpretation |
|---|---|---|
| Common name | Vasoactive Intestinal Peptide | Full name for VIP, originally linked to intestinal and vasodilatory activity. |
| Abbreviation | VIP | Common research abbreviation used across neuropeptide, immune and pulmonary literature. |
| CAS number | 40077-57-4 | Common registry number for human, porcine and rat VIP sequence references. |
| Peptide length | 28 amino acids | VIP is a short endogenous signaling peptide. |
| Primary receptors | VPAC1 and VPAC2 | Major receptor systems used to interpret VIP signaling. |
| Related receptor biology | PACAP and PAC1 context | VIP and PACAP receptor families overlap in class B GPCR signaling research. |
| Research-use status | Laboratory research only | Not for human consumption, veterinary use, diagnostic use, therapeutic use or inhalation use. |
VIP primarily signals through VPAC1 and VPAC2 receptors, which belong to the class B G-protein-coupled receptor family. These receptors are commonly linked to adenylate cyclase activation and intracellular cAMP signaling.
| Pathway Component | Research Role | Why It Matters for VIP |
|---|---|---|
| VPAC1 receptor | Class B GPCR activated by VIP and PACAP-related ligands. | Studied in immune, gastrointestinal, endocrine and epithelial signaling contexts. |
| VPAC2 receptor | Class B GPCR with distinct tissue expression and signaling profile. | Studied in immune regulation, circadian biology, smooth muscle and neuroendocrine research. |
| PAC1 receptor context | Primarily PACAP-selective receptor with lower VIP relevance depending on model. | Important when comparing VIP and PACAP receptor pharmacology. |
| Adenylate cyclase | Enzyme activated downstream of Gs-coupled receptor signaling. | Connects VIP receptor activation to increased cAMP in many experimental systems. |
| cAMP signaling | Second messenger pathway involved in cellular regulation. | Key readout in VIP receptor activation models. |
| Tissue context | Local receptor expression, enzyme activity and immune state shape VIP response. | Explains why VIP may produce different findings across gut, lung, immune and CNS models. |
VIP has one of the broadest research profiles among neuropeptides. It is studied in gut, lung, immune, vascular, endocrine, circadian and central nervous system models.
| Research Area | What Is Being Studied | Important Limitation |
|---|---|---|
| Gastrointestinal research | Gut motility, epithelial signaling, intestinal homeostasis, glucose-related gut-brain pathways and smooth-muscle regulation. | Gut signaling studies should not be converted into digestive or therapeutic claims. |
| Pulmonary research | Bronchial smooth muscle, pulmonary vascular tone, inflammatory signaling and respiratory epithelial models. | VIP should not be framed as an inhaled therapy or respiratory treatment on a research product page. |
| Immune signaling | Macrophage response, cytokine signaling, regulatory lymphocyte pathways, inflammation and immune tolerance models. | Immune modulation research should not become immune-treatment or disease-prevention language. |
| Vascular biology | Vasoregulatory signaling, smooth-muscle relaxation and endothelial interaction models. | Vascular mechanism research should not become blood-pressure or circulatory health claims. |
| Central nervous system research | Neurotransmission, hippocampal signaling, affect-related models, neuroprotection and brain-gut peptide research. | CNS findings should not be converted into mood, cognition or anxiety claims. |
| Circadian and neuroendocrine research | VPAC2 signaling in clock-related circuits and neuroendocrine regulation. | Circadian pathway research should not be described as a sleep-treatment claim. |
VIP is sometimes grouped with peptides studied in immune, gut, CNS, mitochondrial or tissue-repair contexts. Its receptor system and research interpretation are distinct.
| Compound | Primary Research Pathway | How It Differs From VIP |
|---|---|---|
| VIP | VPAC1, VPAC2 and cAMP-linked neuroimmune signaling | Broad neuropeptide with gut, lung, immune, vascular and CNS research relevance. |
| KPV | Alpha-MSH fragment and immune-inflammatory signaling research | More focused on melanocortin-related anti-inflammatory models, not VPAC receptor signaling. |
| Thymosin Alpha-1 | Immune signaling and T-cell pathway research | Immune peptide with a different receptor and immunological profile. |
| Selank | CNS peptide research involving anxiolytic and neuroimmune models | CNS-focused peptide category, not primarily VPAC receptor biology. |
| Semax | CNS, neurotrophic and melanocortin-related research | Different peptide family and pathway emphasis than VIP. |
| BPC-157 | Tissue repair, angiogenesis and gut-related injury models | Repair-model peptide, not a VPAC receptor agonist. |
| MOTS-C | Mitochondrial-derived peptide and metabolic signaling | Mitochondrial metabolic peptide, not a neuroimmune VPAC signaling peptide. |
| SS-31 | Mitochondrial membrane, cardiolipin and oxidative stress pathways | Mitochondria-targeting peptide, not a VPAC receptor peptide. |
VIP is best categorized as a VPAC receptor neuropeptide. KPV and Thymosin Alpha-1 are more immune-focused. Selank and Semax are more CNS-focused. BPC-157 is more repair-model focused. MOTS-C and SS-31 are more mitochondrial-focused.
VIP has a broad literature base across physiology, immunology, gastroenterology, pulmonary biology and neuroscience. Its evidence should be interpreted by model type and receptor context rather than treated as one uniform effect.
| Evidence Area | What the Literature Reports | Research Interpretation |
|---|---|---|
| VIP physiology | Reviews describe VIP as a pleiotropic peptide with roles in vasodilation, secretion, smooth muscle, immune signaling and neuroendocrine regulation. | Supports VIP as a broad regulatory peptide rather than a single-purpose molecule. |
| VPAC receptor pharmacology | VIP and PACAP exert effects through VPAC1, VPAC2 and PAC1 receptor-family biology. | Receptor subtype and tissue expression are essential for interpretation. |
| Pulmonary research | Studies have explored inhaled VIP and VIP pathway biology in pulmonary arterial hypertension, COPD, asthma and lung inflammatory models. | Clinical or inhaled-drug studies should not be converted into instructions for research material. |
| Immune research | VIP is studied in macrophages, cytokine signaling, regulatory immune pathways and inflammatory models. | Immune modulation does not justify immune-treatment or disease-prevention claims. |
| Gastrointestinal research | VIP signaling has been studied in intestinal homeostasis, gut motility, glucose-related gut-brain pathways and epithelial regulation. | Gut pathway evidence should remain mechanistic and research-only. |
| CNS research | VIP is studied in neurotransmission, affect-related models, neuroprotection, hippocampal signaling and brain-gut peptide networks. | CNS associations should not be framed as mood or cognitive claims. |
VIP research is scientifically rich but not simple. Its effects depend on receptor expression, tissue compartment, inflammatory state, nervous-system context, peptide stability and local signaling environment.
The strongest scientific framing is conservative: VIP is a 28-amino-acid neuropeptide used in laboratory research to study VPAC receptor signaling, cAMP-linked pathways, neuroimmune regulation, gut-brain biology, pulmonary signaling and vascular smooth-muscle models.
VIP is a short bioactive peptide, so research quality depends on identity, purity, sequence confirmation, lot-level traceability, storage guidance and clear research-use-only labeling.
| Standard | Why It Matters |
|---|---|
| Batch-specific COA | Connects the material to lot-level analytical documentation. |
| HPLC purity verification | Supports purity evaluation and impurity visibility. |
| Mass spectrometry identity confirmation | Supports molecular identity confirmation for a 28-amino-acid peptide. |
| Clear compound naming | Reduces confusion between VIP, PACAP, VIP fragments and unrelated neuropeptides. |
| Storage and handling guidance | Reduces avoidable degradation, moisture exposure and freeze-thaw variability. |
| Research-use-only labeling | Keeps the material separated from consumer, clinical, inhaled, therapeutic or human-use positioning. |
These answers cover the most common VIP, Vasoactive Intestinal Peptide, VPAC receptor and neuroimmune signaling research questions in 2026.
VIP stands for Vasoactive Intestinal Peptide. It is a 28-amino-acid neuropeptide studied in gastrointestinal, pulmonary, vascular, immune, endocrine and central nervous system research.
The common CAS number for Vasoactive Intestinal Peptide is 40077-57-4. Researchers should confirm the exact sequence, salt form, purity and supplier documentation when comparing materials.
VIP primarily activates VPAC1 and VPAC2 receptors, which are class B G-protein-coupled receptors commonly linked to adenylate cyclase and cAMP signaling. VIP also appears in PACAP-related receptor biology discussions.
No. VIP and PACAP are related peptide-family members with overlapping receptor biology, but they are distinct peptides. VIP is mainly discussed through VPAC1 and VPAC2 receptors, while PACAP has stronger relevance to PAC1 receptor signaling.
VIP is studied for gastrointestinal signaling, smooth-muscle regulation, pulmonary biology, vascular tone, immune modulation, cytokine signaling, circadian biology, neuroendocrine regulation and central nervous system models.
VIP is not only an immune peptide, but it is studied in immune signaling models. Research includes macrophage biology, cytokine regulation, regulatory lymphocyte pathways and inflammatory response models.
No. Luxara Labs VIP is supplied strictly for laboratory research use only. It is not intended for human consumption, inhalation, veterinary use, diagnostic use, therapeutic use or cosmetic use.
VIP is a VPAC receptor neuropeptide with broad gut, lung, immune, vascular and CNS research relevance. KPV is an alpha-MSH fragment studied in inflammatory models, while Thymosin Alpha-1 is studied in immune and T-cell pathway research.
Researchers should look for batch-specific COAs, HPLC purity documentation, mass spectrometry identity confirmation, sequence clarity, lot numbers, storage guidance and research-use-only labeling.
Luxara Labs carries VIP as a research-use-only peptide. The product page is available at https://luxaralabs.com/product/vip/.
These references support the VIP, VPAC1, VPAC2, cAMP, pulmonary, immune, gastrointestinal, CNS, vascular and research-use context discussed on this page.
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