● pepmg Research Desk · Peer-reviewed evidence review
What the research says about VIP
A neutral summary of the peer-reviewed literature on vasoactive intestinal peptide (VIP), a 28-amino-acid endogenous neuropeptide that acts as a potent vasodilator and immune modulator, with human evidence concentrated in physiology rather than therapeutic trials. Research use only.
Moderate evidence — Limited human trials — often early-phase. This describes the state of the published literature, not a claim that this compound works, is safe, or is for human use. Research use only.
The short version
- VIP (vasoactive intestinal peptide) is a 28-amino-acid endogenous neuropeptide found throughout the nervous system, gut, heart, and lungs; it acts as a non-adrenergic, non-cholinergic neurotransmitter, a potent vasodilator, and an immune regulator [1][2].
- As a vasodilator it is reported to be far more potent than acetylcholine, and its dilator action in humans has been studied directly in controlled physiology experiments [2][3].
- Most disease-oriented work, in cardiac fibrosis, metabolism, and lung disease, is preclinical or early, and reviews note that VIP's own clinical use is constrained by its very short half-life [4][5][6].
- This page reports what the studies measured. It is not medical advice, an efficacy or safety claim, or dosing guidance. Research use only.
What VIP is
Vasoactive intestinal peptide is described in the literature as a 28-amino-acid neuropeptide, widely distributed in the central and peripheral nervous systems and present in significant concentrations in the gastrointestinal tract, heart, lungs, thyroid, kidney, urinary bladder, genital organs, and brain [1][2]. It is released by both neurons and immune cells and acts through its receptors (including VPAC1 and VPAC2) as a neurotransmitter, vasodilator, immune regulator, and secretagogue [1].
Its signature pharmacology is vasodilation: on a molar basis, reviews describe VIP as many times more potent than acetylcholine as a vasodilator, acting largely through nitric-oxide-dependent pathways [2]. VIP is a naturally occurring human signaling molecule; the synthetic form is also studied under other names in specific clinical settings. Material sold by research-chemical vendors is not an approved pharmaceutical product and is offered for laboratory and research use only.
What the research has measured
Moderate evidenceVIP's vasodilator role has been probed in controlled human physiology. In studies of skin blood flow during heat stress, investigators used the VIP fragment VIP(10-28) to antagonize VIP-mediated dilation and dissected its dependence on nitric-oxide and histamine-H1 pathways, establishing a specific role for VIP in active vasodilation in people [3]. Reviews of VIP's cardiovascular effects place this within a broader body of work on VIP as a neurotransmitter and vasodilator across many organs [2].
Beyond vasodilation, much of the therapeutically motivated work is preclinical. In Wistar Kyoto rats with salt-induced myocardial fibrosis, an infusion of VIP was tested to see whether replenishing myocardial VIP could treat fibrosis, on the observation that cardiac VIP falls as fibrosis progresses [4]. In metabolism, reviews describe VIP stimulating glucose-dependent insulin secretion, particularly via the VPAC2 receptor, and promoting islet beta-cell proliferation, motivating interest in VPAC2-selective agonists for type 2 diabetes [5]. In the lungs, VIP is an abundant mediator studied across pulmonary arterial hypertension, COPD, asthma, cystic fibrosis, acute lung injury, and, more recently, COVID-19 [6].
VIP is also extensively characterized as an immune modulator, with reviews detailing direct effects on immune cells and roles in inflammatory and autoimmune conditions [1][7]. Across these areas, the recurring theme is a well-mapped endogenous peptide with strong mechanistic and physiological support, but with disease applications that are largely at the preclinical or early stage in this corpus.
What the studies report on safety and adverse events
Moderate evidenceThe corpus is weighted toward physiology, mechanism, and receptor pharmacology rather than tabulated adverse-event data, so it is not a comprehensive safety review. The most direct practical constraint reported is pharmacokinetic: reviews note that the clinical application of native VIP is limited by its very short half-life and its wide distribution and activity throughout the body, which is precisely why researchers pursue stabilized analogs and receptor-selective agonists rather than native VIP [5]. A molecule that is a potent vasodilator and acts on many organ systems is, by its nature, capable of broad physiological effects.
Because the human data here are largely short physiology experiments and the disease work is preclinical, this corpus does not contain long-term controlled safety trials of VIP administration for any of the marketed uses.
None of this is a safety guarantee. VIP is a potent, broadly acting signaling peptide, and research-chemical material is not manufactured to pharmacy standards. This is not medical advice; consult a qualified professional and read the studies directly.
How strong is the evidence
The evidence base is characterized as moderate, and the scope is specific. VIP is a thoroughly characterized endogenous neuropeptide: its identity, receptors, and potent vasodilator and immunomodulatory actions are well established, and its vasodilator physiology has been examined in controlled human experiments [1][2][3]. "Moderate" is bound to that physiology and mechanism.
It is not evidence that administering VIP treats any particular disease: the cardiac, metabolic, and pulmonary applications are preclinical or early [4][5][6], and native VIP's short half-life is a real obstacle to therapeutic use [5]. Nothing here is dosing, medical, or safety guidance. Read the studies themselves and consult a qualified professional. This page is a map to the evidence, not a recommendation.
Sources · 7
- Vasoactive intestinal peptide: a neuropeptide with pleiotropic immune functions.
- Vasoactive intestinal peptide: cardiovascular effects.
- Vasoactive intestinal peptide fragment VIP10-28 and active vasodilation in human skin.
- Vasoactive intestinal peptide infusion reverses existing myocardial fibrosis in the rat.
- Therapeutic potential of vasoactive intestinal peptide and its receptor VPAC2 in type 2 diabetes.
- The role of vasoactive intestinal peptide in pulmonary diseases.
- The neuropeptide vasoactive intestinal peptide: direct effects on immune cells and involvement in inflammatory and autoimmune diseases.
pepmg summarizes the peer-reviewed literature and links to every source — it sells nothing, ships nothing, and gives no medical, dosing, or human-use guidance. Don't just trust this summary: follow any citation to its source and read it yourself. Research use only.