PULMONARY, VASCULAR & IMMUNE SIGNALLING
VIP
A naturally occurring signalling peptide with wide-ranging research into breathing, circulation, inflammation and gut health.
Pulmonary vasodilationAirway biologyImmune modulation
Human pulmonary studies exist, but efficacy remains unestablishedA small study found modest, short-lived pulmonary vasodilation after inhaled aviptadil. A much larger intravenous COVID-19 trial stopped for futility and found no clinical benefit.
FOLLOW THE FULL PICTUREFrom interest to evidence, quality and the numbers.
Why does VIP attract such broad research interest?
VIP is naturally active in the nerves, lungs, blood vessels, immune system and gut. That unusually wide reach is exactly why it attracts interest: researchers are exploring whether its effects on circulation, inflammation, breathing and digestion could be useful in very different areas of health.
Lung-protective signalling
Aviptadil is explored around alveolar cells, surfactant and inflammatory lung injury.
Explore the research →Inflammation & immune balance
VIP can influence cytokines and immune-cell behaviour experimentally.
Explore the research →Gut–brain signalling
VIP is an enteric neurotransmitter involved in secretion, motility and smooth-muscle relaxation.
Explore the research →THE SCIENCE BIT
A widespread message carried by VPAC receptors.
Vasoactive intestinal peptide, or VIP, activates VPAC1 and VPAC2 receptors. These receptors can raise cAMP, a messenger inside cells, and influence smooth muscle, secretion and immune responses.
The same peptide can therefore have different effects in lungs, vessels and the gut. Human aviptadil studies test particular routes and conditions, rather than every potential role of naturally occurring VIP.
See the studies & trials →- VPAC1 / VPAC2
- The main receptor family
- cAMP
- An intracellular messenger
- Smooth muscle
- Relaxation-related signalling
How this connects to the research
Established physiology with condition- and route-specific clinical uncertainty.
FROM MOLECULE TO TISSUE
Where VIP connects with the body
These are the tissues and biological systems behind the interest in VIP.
- Lungs and vessels
- Pulmonary and circulation research.
- Gut
- Secretion and neural signalling.
- Immune cells
- Inflammatory responses.
The research behind the interest
Pulmonary vasodilation
VIP can relax pulmonary vascular smooth muscle.
Twenty patients inhaled 100 micrograms during right-heart catheterisation; the effect was selective but modest and short-lived.
Small human mechanistic studyExplore the studies →Lung-protective signalling
Aviptadil is explored around alveolar cells, surfactant and inflammatory lung injury.
The rationale reached large trials, but intravenous treatment did not improve 90-day outcomes in TESICO.
Human efficacy not establishedExplore the studies →Inflammation & immune balance
VIP can influence immune signalling, creating interest around whether it might help regulate excessive inflammation in particular disease settings.
Context-dependent signalling does not establish general ‘immune support’ or a safe injectable protocol.
Strong mechanism; limited translationExplore the studies →Gut–brain signalling
VIP is an enteric neurotransmitter involved in secretion, motility and smooth-muscle relaxation.
Endogenous physiology does not show that administered VIP improves digestion, dysbiosis or ‘gut healing’.
Established physiology; claim unprovenExplore the studies →Studies & trials
Studies & trials
Original publication · PubMed · trial registry where availableInhaled aviptadil in pulmonary hypertension ↗
20 adults with chronic pulmonary hypertension
Inhaled aerosolSingle 100 microgram research doseRight-heart catheterisation session
Modest, temporary selective pulmonary vasodilation and improved stroke volume.
Six participants had pulmonary vascular-resistance reductions above 20%; no acute side effects were reported.
TESICO intravenous aviptadil trial ↗
461 treated adults with COVID-19 hypoxaemic respiratory failure
Intravenous infusionEscalating weight-based infusion over three daysThree treatment days; 90-day outcome
The monitoring board recommended stopping for futility.
Aviptadil did not improve 90-day clinical outcome or mortality.
Inhaled aviptadil high-risk COVID-19 programme ↗
132 hospitalized adults at high risk of ARDS
InhaledProtocol-defined repeated inhalationHospital treatment
The paper documents rationale, route and planned outcomes—not a proven effect.
Small later findings require interpretation beside the larger negative IV programme.
Evidence snapshot
Evidence snapshot
Separate dimensions, not one overall score◎
Human evidenceStrong
4/5 evidence depth
Aviptadil has been administered in pulmonary hypertension and respiratory-failure studies.
✓
Clinical efficacyLimited
2/5 evidence depth
Small physiological signals have not become established benefit; TESICO was negative.
◇
Safety evidenceDeveloping
3/5 evidence depth
Trials provide route-specific short-term data, not repeated self-use safety.
⌁
Preclinical evidenceStrong
4/5 evidence depth
Substantial receptor, vascular, pulmonary, intestinal and immune research supports plausibility.
HOW TO READ THESE SCORESStrong preclinical evidence · strong human evidence
These are editorial evidence-depth ratings on a 1–5 scale, not a statistical result or a single scientific formula. They summarise how much relevant evidence is present in each separate category and how mature that evidence is.
Human evidenceHow much direct research in people is available and how developed it is.
Clinical efficacyWhether human studies demonstrate meaningful outcomes for the claims being discussed.
Safety evidenceHow much human safety, tolerability and longer-term follow-up information is available.
Preclinical evidenceThe depth of laboratory and animal research supporting biological plausibility.
EVIDENCE LANDSCAPEVIPBiology → route → human outcome
Inhaled and intravenous pulmonary programmes
Large critical-COVID trial was negative
No chronic pulmonary or wellness schedule
Keep each claim attached to its route and outcome
An active biological pathway can justify a trial. It cannot make an untested formulation, indication or long-term schedule evidence-based.
From promising signals to human evidencePreclinical research can reveal promising biological signals. Human studies show how far those signals have translated into real-world outcomes.
What people are exploring
COMMUNITY · USE CASES & EXPERIENCE
What people want to change with VIP
VIP is explored for breathing, post-viral recovery, immune balance and gut–brain symptoms. It has genuine human pulmonary research, but positive narratives must be read beside modest acute physiology and a negative large intravenous trial.
Explore the everyday goalsConceptual scientific illustration
THE PRACTICAL ATTRACTION
The goals behind the interest
What the desired change means in daily life, and what makes an experience useful to understand.
Breathing and pulmonary recovery
Interest often concerns respiratory illness, oxygenation or recovering lung function. These are clinical outcomes that need objective measurements and the appropriate disease context.
- What makes a report informative
- Respiratory function and the exact clinical setting.
- What can muddy the picture
- Feeling less breathless does not identify the cause or establish a VIP effect.
Post-illness resilience and immune questions
People with lingering symptoms may be drawn to anti-inflammatory and immune-signalling research. Findings from acute hospital illness cannot answer whether it helps a long-term post-viral syndrome.
- What makes a report informative
- Daily function and the diagnosis behind the symptoms.
- What can muddy the picture
- Natural recovery, other treatments and disease differences limit comparisons.
Gut and broader signalling interest
VIP biology spans several tissues, which encourages wide-ranging claims. A useful discussion starts with one specific symptom or outcome instead of assuming a whole-body reset.
- What makes a report informative
- The route, target condition and measured outcome.
- What can muddy the picture
- The unsuccessful large IV aviptadil trial must be considered alongside mechanistic interest.
PUT THE EXPERIENCE IN CONTEXT
How the goals compare with the research
Open an area to distinguish human findings from laboratory explanations.
Breathing and pulmonary circulation
People are attracted to the vasodilator and pulmonary story.
Human findings & limits
A 20-person inhalation study found modest, temporary vasodilation.
Laboratory & animal context
VIP receptors occur across pulmonary vascular and airway tissues.
What this means: A credible acute signal that did not establish chronic treatment.
Post-viral lung recovery
Interest expanded during COVID-19 and is extended to prolonged symptoms.
Human findings & limits
TESICO found no clinical or mortality improvement with IV aviptadil.
Laboratory & animal context
Alveolar and inflammatory mechanisms supported the trial rationale.
What this means: The strongest controlled evidence is negative for that setting.
Immune balance
VIP is framed as calming excessive inflammation.
Human findings & limits
No broad immune-support indication or consumer trial exists.
Laboratory & animal context
Effects on cytokines and immune cells are context-dependent.
What this means: Mechanistic depth does not create a general immune therapy.
Gut and neurological symptoms
Users connect enteric roles with digestion, dysautonomia or brain fog.
Human findings & limits
Direct treatment evidence for these clusters is insufficient.
Laboratory & animal context
VIP participates in secretion, motility and neural signalling.
What this means: Established physiology with unproven administered benefit.
Research sources and further reading
Dose & duration
DOSE & DURATION
Research protocols · community patterns · calculator toolsSee the numbers in their proper context
See the amount, how often it was used and how long each study ran. Published human research and community descriptions each carry their own source label, so you can see where the numbers came from.
Source matters. The figures below show authorised, human-research or community-described protocols in their original context — not a personalised recommendation.
VIP/aviptadil research doses are route- and disease-specific; no general subcutaneous dose or wellness cycle has been validated.
No structured human dosing protocol has been added for this compound. That should not be interpreted as evidence for a community dosing schedule.
COMMUNITY DISCUSSION
Published human research exposure · not a self-use protocolWhat people commonly discuss
STARTING APPROACHES
The clearest inhaled physiology study used a single 100 microgram dose under catheterisation monitoring.
DURATION / CYCLES
TESICO used three daily 12-hour IV infusions with weight-based escalation; it was an intensive-care trial, not a titration template.
MAINTENANCE DISCUSSION
No evidence-based maintenance schedule exists for lung health, immune support, gut symptoms or recovery.
Community patterns are anecdotal and unvalidated unless a linked human study independently supports the same approach.
CALCULATOR TOOLS
Work with the numbers
Convert amounts, concentration, liquid volume and vial requirements. These tools do the arithmetic; they do not select a dose.
NEED HELP READING THE NUMBERS?Source labels, routes and dose termsOpen guide +
HOW WE LABEL NUMBERSKnow where a dose came from before you compare it.
Authorised labelHuman trialCommunity-describedBEFORE THE NUMBERS: CHECK THE PRODUCT
Understand peptide testing →A dose only means something if the vial contains what the label says.
Purity, identity, quantity, sterility and endotoxin testing answer different questions. Learn how to read a COA and why a high purity percentage is not the same as confirming the amount in the vial.
READ THIS PAGE IN THREE STEPS
Understand the study before the number
A dose only makes sense alongside the population, route, frequency and duration. Start with where the number came from, then look at how it was delivered and how long the study actually ran.
1Source
Was it an authorised label, a human trial or a community-described pattern?
2Route & frequency
How was it given, and how often? The same number by a different route may not mean the same exposure.
3Duration
Was this one dose, a short trial or long-term treatment? A study window is not automatically a recommended cycle.
ROUTES EXPLAINED
Plain-English guideWhat do the injection types mean?
Route means how a compound was delivered. It affects absorption and can completely change how a study should be interpreted.
SubQ / SCSubcutaneous
An injection into the fatty layer just under the skin.
Common in peptide and metabolic-drug studies. It usually aims for systemic absorption rather than treating only the spot injected.IMIntramuscular
An injection into muscle tissue.
Muscle can absorb a medicine differently from fat. An IM amount should not be assumed to be equivalent to a SubQ amount.IVIntravenous
Delivered directly into a vein.
This gives immediate bloodstream exposure and is commonly used in supervised research or clinical settings. It is not interchangeable with a home injection route.INIntranasal
Delivered through the nose rather than by injection.
The amount delivered depends on formulation and device. A spray count alone does not tell you the dose unless concentration and spray volume are known.Other routes you may see:Oral = swallowed.Topical = applied to skin or another surface.Implant = a formulation placed under the skin by a trained professional.
CALENDAR SETUP
Specialist inhalation and infusion guide
Human research · monitored pulmonary treatmentPublished studies used monitored inhalation or weight-based intensive-care infusions. A dose rate per hour cannot be copied as an amount per injection reminder. Record a specialist schedule or appointment; no community subcutaneous programme is inferred.
Form and route: Inhaled or intravenous aviptadil research formulations
The planner keeps amounts and repeat patterns blank for this compound. Use its formulation guide to record an independently specified schedule.
PLAIN-ENGLISH GLOSSARYWhat do the dose terms mean?Open glossary +
mgmilligram
One thousand micrograms (mcg).
mcg / μgmicrogram
One thousandth of a milligram.
mcg/kgweight-based dose
The amount is calculated for each kilogram of body weight.
IUinternational unit
A measure of biological activity used for some medicines; it cannot be converted to mg without compound-specific information.
Routehow it was given
For example SubQ, IM, IV, intranasal, oral or topical.
Frequencyhow often
For example once daily, twice weekly or every seven days.
Titrationplanned step-up or step-down
A protocol changes the amount over time rather than using one fixed amount throughout.
Half-lifehow quickly levels fall
The time taken for the amount of a compound in the body to reduce by roughly half. It can influence study timing but does not by itself define a schedule.
Cyclea defined period of use
Usually means an on-period followed by a stop or review. Many community 'cycles' have not been clinically validated.
Maintenancea continuing phase
A longer-term amount or interval used after an initial phase when a study or authorised treatment actually defines one.
Reconstitutionturning powder into solution
Adding a specified liquid to a freeze-dried vial so a concentration can be calculated.
U-100 unitssyringe volume markings
100 units equals 1 mL on a U-100 insulin syringe. The markings show volume, not peptide mass.
Often combined with
OFTEN COMBINED WITH
Community rationale · component roles · evidence boundaryWhy people explore pairings with VIP
See the thinking behind community-named stacks, the different role each component is proposed to play, and how much of that idea has actually been tested as a combination.
Potential first, evidence in context. Pairings are usually explored because their research stories appear complementary. That makes them interesting to study, but does not yet prove extra benefit or safety.
CURRENT COMPOUNDVIP
→
OFTEN EXPLORED WITHAviptadil + pulmonary care
Aviptadil research treatment + Respiratory care
→
OFTEN EXPLORED WITHVIP + antimicrobial peptides
VIP + LL-37 or another immune-active peptide
→
OFTEN EXPLORED WITHVIP + BPC-157
VIP + BPC-157
Combination-specific human research is the strongest evidence for what a pairing adds. Evidence for either ingredient alone should not be silently transferred to the combination.
＋
OFTEN EXPLORED WITH
Explore →＋Aviptadil + pulmonary care
Aviptadil research treatment + Respiratory careWHY IT IS EXPLOREDTrials used monitored hospital or catheterisation settings.
Research context only; efficacy depends on disease and route.OFTEN EXPLORED WITH
Explore →＋VIP + antimicrobial peptides
VIP + LL-37 or another immune-active peptideWHY IT IS EXPLOREDDiscussed as complementary immune signalling.
No controlled human combination evidence establishes benefit or safe dosing.OFTEN EXPLORED WITH
Explore →VIP + BPC-157
VIP + BPC-157WHY IT IS EXPLOREDCommunity interest combines gut-neural signalling with tissue protection.
No human study validates synergy, route or interaction safety.Safety context
SAFETY & UNCERTAINTY
Vasodilation and route-specific exposure need clinical context
What the current evidence saysVIP can affect vascular tone, heart rate, fluid movement and gastrointestinal secretion. Hypotension, flushing, diarrhoea and tachycardia are plausible or reported concerns depending on route.
01 · OBSERVEDPublished safety findings
The summary above reflects the human or preclinical evidence currently represented on this profile.
02 · UNCERTAINGaps still matter
Limited follow-up, small studies or absent controlled trials can leave uncommon and longer-term risks unresolved.
03 · CONTEXTProduct and regulatory status
Route, product identity, quality and regulatory status can materially change the safety context; see the linked status sources below.
Why this matters
Short endogenous half-life does not make repeated dosing safe, and retail subcutaneous products are not equivalent to clinical formulations.
Sources & current status
READ FURTHER
Sources & current status
Follow the professional sources used across this profile, then see how the compound is currently described in regulatory and research terms.
KEY RESEARCH RECORD
10 sourcesSources used on this profile
Original publicationInhaled aviptadil in pulmonary hypertensionJournal / DOI ↗Bibliographic recordInhaled aviptadil in pulmonary hypertensionPubMed ↗Original human trialTESICO intravenous aviptadil trialFree full paper ↗Original publicationTESICO intravenous aviptadil trialJournal / DOI ↗Bibliographic recordTESICO intravenous aviptadil trialPubMed ↗Trial registryTESICO intravenous aviptadil trialClinicalTrials.gov ↗Clinical trial protocolInhaled aviptadil high-risk COVID-19 programmeFree protocol ↗Bibliographic recordInhaled aviptadil high-risk COVID-19 programmePubMed ↗Professional sourceUnited KingdomMHRA products database ↗Professional sourceUnited StatesDrugs@FDA ↗
CURRENT STATUS
How to interpret its position today
No UK-authorised medicine identified
VIP / aviptadil is presented as an experimental compound. Product identity, quality and supply sit outside an approved prescribing pathway.
MHRA products database ↗No FDA-approved therapeutic product identified
A published experiment is not approval for safety and efficacy.
Drugs@FDA ↗Profile reviewed against its linked source record on 20 September 2026. See how evidence is assessed.