VIP

VIP (vasoactive intestinal peptide) is a 28‑amino‑acid neuropeptide that acts as a widespread signaling molecule in the body Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. First isolated in the early 1970s, it is now understood to play roles in immune regulation, gut health, circadian rhythms, and blood vessel function Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. Research focuses on its ability to dampen harmful inflammation, protect gut barrier function, and coordinate the body's internal clock Vasoactive intestinal peptide promotes host defense against enteric pathogens by modulating the recruitment of group 3 innate lymphoid cells+1. Unlike many peptides, VIP has been studied directly in human subjects for migraine and lung disease, though most evidence still comes from animal and laboratory studies The Effects of a Long-lasting Infusion of Vasoactive Intestinal Peptide (VIP) in Episodic Migraine Patients+1.

VIP works by binding to two main receptor types, VPAC1 and VPAC2, which are found on many cell types including immune cells, gut lining cells, and neurons Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. When activated, these receptors trigger a rise in a messenger molecule called cyclic AMP (cAMP) inside the cell Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system. This cascade leads to changes such as relaxation of blood vessels (vasodilation), increased fluid and electrolyte secretion in the intestines, and a shift in the immune system's inflammatory output Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. In the brain's biological clock (the suprachiasmatic nucleus), VIP signaling helps synchronize daily rhythms by activating the ERK pathway Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling. The peptide's effects are highly context‑dependent; for instance, in inflammatory conditions, VIP may become chemically modified (nitrated) and lose some of its potency Heme and Cu2+-induced vasoactive intestinal peptide (VIP) tyrosine nitration: A possible molecular mechanism for the attenuated anti-inflammatory effect of VIP in inflammatory diseases.

Research has documented several biological effects of VIP:

• Anti‑inflammatory action: VIP strongly reduces the production of inflammatory cytokines like TNF‑α and IL‑6, and in animal models of severe infection (endotoxemia) it improves survival Vasoactive Intestinal Peptide (VIP) and Pituitary Adenylate Cyclase-Activation Polypeptide (PACAP) Protect Mice from Lethal Endotoxemia Through the Inhibition of TNF-α and IL-6. In experimental colitis, VIP delivered in specialized nanoparticles markedly improved symptoms and tissue healing Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease.
• Gut immunity and host defense: VIP helps recruit a specific immune cell type (ILC3) to the intestine, which supports production of IL‑22 and strengthens defenses against gut pathogens Vasoactive intestinal peptide promotes host defense against enteric pathogens by modulating the recruitment of group 3 innate lymphoid cells. Mice lacking VIP are more susceptible to intestinal infection.
• Circadian clock synchronization: VIP is a key communicator between clock neurons in the brain, keeping the body's daily rhythms aligned Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling.
• Neuroprotection: VIP has shown protective effects in animal models of Parkinson's disease by reducing harmful microglial activation Neuroprotective effect of vasoactive intestinal peptide (VIP) in a mouse model of Parkinson's disease by blocking microglial activation+1.
• Vasodilation and vascular effects: VIP relaxes blood vessels, which can lower blood pressure and cause flushing. This property is explored for lung conditions like COPD, where inhaled VIP improved walking distance in a small clinical trial INHALED VASOACTIVE INTESTINAL PEPTIDE (VIP) IMPROVES THE 6-MINUTE WALK TEST AND QUALITY OF LIFE IN PATIENTS WITH COPD: THE VIP/COPD-TRIAL.
• Ocular effects: Local injection of VIP into the eye slowed the development of myopia (nearsightedness) in guinea pigs by regulating tissue growth pathways Vasoactive intestinal peptide attenuates form-deprivation myopia in guinea pigs by suppressing the Wnt/β-catenin pathway along the retina-choroid-scleral axis.

No single standardized human dosing protocol for VIP exists in the research literature due to the peptide's rapid degradation and side‑effect profile Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease+1. Instead, protocols vary by route and formulation. The most common routes studied are subcutaneous injection, intravenous infusion, and inhalation, each with distinct advantages and limitations.

Subcutaneous (SC) protocols are commonly used in community‑based research. Starting doses are typically low (25‑50 mcg) to assess tolerance, as vasodilation can cause dizziness or headache. Doses are increased gradually (by 25‑50 mcg every 3‑4 days) until a beneficial effect is seen or side effects become limiting. Typical maintenance doses range from 50‑200 mcg once or twice daily. Cycles often run 4‑8 weeks, sometimes with a 5‑days‑on/2‑days‑off pattern to minimize receptor desensitization Structure-activity relationship of vasoactive intestinal peptide (VIP): potent agonists and potential clinical applications.

Intravenous (IV) infusion has been used in human migraine research, where long‑lasting infusion paradigms are employed to study VIP's role in headache disorders The Effects of a Long-lasting Infusion of Vasoactive Intestinal Peptide (VIP) in Episodic Migraine Patients. This route provides precise control but is impractical for outpatient settings.

Inhaled VIP was studied in a small COPD trial, showing improvements in exercise capacity INHALED VASOACTIVE INTESTINAL PEPTIDE (VIP) IMPROVES THE 6-MINUTE WALK TEST AND QUALITY OF LIFE IN PATIENTS WITH COPD: THE VIP/COPD-TRIAL. Dosing details are limited, but this route is attractive for respiratory conditions.

A critical challenge with VIP is its instability: the free peptide is rapidly broken down in the body. Research has shown that incorporating VIP into nanoparticles or micelles greatly improves its durability and reduces side effects like hypotension Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease. Therefore, formulation is as important as dose in determining effectiveness Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease+1.

Proper handling of VIP is important because the peptide is fragile and prone to rapid degradation Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. When preparing VIP for injection, the lyophilized powder should be reconstituted with bacteriostatic water (or sterile water for single use). Add the diluent slowly down the vial wall and swirl gently; avoid shaking to prevent damage to the peptide Structure-activity relationship of vasoactive intestinal peptide (VIP): potent agonists and potential clinical applications. After reconstitution, keep the solution refrigerated and protected from light. Due to VIP's instability, many researchers divide the solution into small aliquots and store them frozen, minimizing freeze‑thaw cycles Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1.

The shelf life of reconstituted VIP in the refrigerator is generally 14‑30 days in bacteriostatic water. The lyophilized powder can be stored at -20°C for up to two years. Always discard any solution that becomes cloudy or contains particles.

Because the dose‑response relationship is influenced by delivery method, the interactive calculator on this page can help determine the volume needed for a specific dose. Always refer to the calculator rather than performing manual calculations, to avoid dosing errors Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease.

VIP's vasodilatory and immunomodulatory actions mean it can interact with several classes of drugs and supplements Vasoactive Intestinal Peptide (VIP) and Pituitary Adenylate Cyclase-Activation Polypeptide (PACAP) Protect Mice from Lethal Endotoxemia Through the Inhibition of TNF-α and IL-6+1.

• Vasodilators and blood pressure medications: Combining VIP with drugs like sildenafil (Viagra), nitrates, or certain antihypertensives can cause an excessive drop in blood pressure, leading to dizziness or fainting Vasoactive Intestinal Peptide Nanomedicine for the Management of Inflammatory Bowel Disease. Caution is advised.
• Bronchodilators: Inhaled VIP may add to the effects of asthma or COPD medications, potentially causing rapid heartbeat or tremors INHALED VASOACTIVE INTESTINAL PEPTIDE (VIP) IMPROVES THE 6-MINUTE WALK TEST AND QUALITY OF LIFE IN PATIENTS WITH COPD: THE VIP/COPD-TRIAL.
• Immunosuppressants: VIP's complex immune effects (both suppressing some cytokines and promoting other immune pathways) mean that combining it with corticosteroids, biologics, or JAK inhibitors could alter immune function unpredictably Vasoactive intestinal peptide promotes host defense against enteric pathogens by modulating the recruitment of group 3 innate lymphoid cells+2.
• Diabetes medications: VIP can enhance insulin secretion, so blood glucose should be monitored if used with insulin or sulfonylureas Vasoactive intestinal peptide (VIP) conducts the neuronal activity during absence seizures: GABA seems to be the main mediator of VIP.
• Oxidative stress‑related supplements: Copper and heme can chemically modify VIP, reducing its anti‑inflammatory activity, so unnecessary high‑dose copper supplements are best avoided Heme and Cu2+-induced vasoactive intestinal peptide (VIP) tyrosine nitration: A possible molecular mechanism for the attenuated anti-inflammatory effect of VIP in inflammatory diseases.

In general, it is advisable to introduce VIP alone for several days before adding other peptides or vasoactive agents to assess individual response.

In research settings, VIP is sometimes combined with other peptides to target different aspects of a condition Vasoactive Intestinal Peptide (VIP) and Pituitary Adenylate Cyclase-Activation Polypeptide (PACAP) Protect Mice from Lethal Endotoxemia Through the Inhibition of TNF-α and IL-6. For example:

• BPC‑157 / TB‑500: Commonly paired for "healing plus anti‑inflammatory" purposes. These combinations are based on overlapping interest in gut repair and tissue healing, though no formal interaction studies exist. The main practical concern is additive blood pressure effects.
• PACAP (Pituitary Adenylate Cyclase‑Activating Polypeptide): Shares receptor pathways with VIP and similarly suppresses inflammatory cytokines Vasoactive Intestinal Peptide (VIP) and Pituitary Adenylate Cyclase-Activation Polypeptide (PACAP) Protect Mice from Lethal Endotoxemia Through the Inhibition of TNF-α and IL-6. Stacking may provide redundant benefits but could amplify vasodilation.
• GLP‑1 agonists (e.g., semaglutide): VIP can enhance glucose‑dependent insulin secretion, so combining with GLP‑1s might strengthen glycemic control but could increase gastrointestinal side effects like nausea Vasoactive intestinal peptide (VIP) conducts the neuronal activity during absence seizures: GABA seems to be the main mediator of VIP.

For safety, it is best to add one peptide at a time, starting with low doses, and monitor for hypotension, gastrointestinal symptoms, or unusual immune effects.

VIP is not FDA‑approved for any indication Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. It is considered an investigational compound, although it has been administered to human subjects in clinical trials for migraine and COPD The Effects of a Long-lasting Infusion of Vasoactive Intestinal Peptide (VIP) in Episodic Migraine Patients+1. Legally, it falls under research chemical or compounded peptide categories, and is not scheduled by the DEA. For athletes, there is no specific mention of VIP on the WADA Prohibited List, but its peptide nature and injection route make it a high‑risk substance that should be checked against the current list before competition. Internationally, VIP is not approved as a medicine in the EU, UK, or Australia, though country‑specific named‑patient importation pathways may allow access under medical supervision.

The main side effects of VIP are related to its vasodilatory and gastrointestinal actions Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system+1. Commonly reported effects include facial flushing, dizziness, headache, and loose stools. These are generally dose‑dependent and manageable by lowering the dose Recent advances in vasoactive intestinal peptide physiology and pathophysiology: focus on the gastrointestinal system.

Common effects:

• Flushing and warmth
• Lightheadedness (due to blood pressure drop)
• Headache (may be migraine‑like)
• Loose stools or diarrhea
• Fatigue (from low blood pressure)

Uncommon effects:

• Heart palpitations or rapid heartbeat (reflex tachycardia)
• Nasal congestion or cough (especially with inhaled forms)
• Paradoxical immune activation in some contexts The effects of vasoactive intestinal peptide in neurodegenerative disorders+1

Serious risks:

• Severe hypotension, fainting (especially when combined with other vasodilators)
• Unknown long‑term cancer risk in receptor‑positive tumors (theoretical)
• Unknown effects on hormone levels (prolactin, vasopressin) Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling+1

Because VIP's effects are context‑dependent, it should be avoided in people with baseline low blood pressure, uncontrolled migraine, or active infections unless monitored closely. Laboratory monitoring may include blood pressure checks, complete blood count, and markers of inflammation like CRP. If severe dizziness, faintness, or persistent diarrhea occurs, the dose should be reduced or stopped.