VIP: what it is and what the evidence says
Vasoactive intestinal peptide, a natural 28-amino-acid neuropeptide that activates the VPAC1 and VPAC2 receptors and raises cyclic AMP. It relaxes blood vessels and airways, modulates the immune response of the mucosa, and synchronizes the circadian clock.
Last reviewed: August 16, 2026 · How we verify this
The ground it plays on
The immune system is not something you turn "up" or "down": it is regulated. A compound that raised the response without control would be a problem, not a benefit, which is why the correct word is modulation. For people with autoimmune or inflammatory conditions, this stops being a technical nuance.
What it is studied for
Immune balance, inflammation modulation, respiratory health.
There is a distinction that almost always gets lost. A compound being studied for something is not the same as achieving it. And even where it works in a dish or in a mouse, that says little about whether it works in a person or whether the benefit is worth the risk. The section below therefore carries more weight than everything above it.
What the human evidence says
Synthetic VIP (aviptadil) was tested in randomized, placebo-controlled trials in COVID-19 respiratory failure, which showed no difference in recovery or mortality, and in an open-label inhaled study in 20 people with sarcoidosis, where TNF alpha fell and regulatory T cells in the lung increased. Combined with phentolamine, it has a comparative study against alprostadil in erectile dysfunction.
The limitation that matters most
Its half-life of about two minutes limits it to hospital infusion or to local routes such as inhalation. A controlled trial confirming the benefit in sarcoidosis is still missing, and autoimmunity and chronic inflammatory conditions do not yet have trials with a comparison group.
Regulatory status
Not approved by the FDA, which in 2021 declined emergency use authorization in COVID-19; on its list of bulk substances for pharmacy compounding it sits in Category 1, under evaluation (May 2026 update). The combination of aviptadil with phentolamine (Invicorp) is authorized in the United Kingdom and Scandinavia for erectile dysfunction, and India authorized its emergency use in 2022 for severe COVID-19 with respiratory distress. It is not listed by name on the 2026 WADA list.
Status can change and varies by country. Always verify the rules in force where you live before drawing conclusions.
Cautions and context
It is a vasodilator, so it can lower blood pressure and cause flushing and dizziness on standing; it can also cause watery diarrhea with potassium loss. It lasts about two minutes in the blood, so the route defines its effect.
With low blood pressure, cardiovascular or respiratory disease, blood pressure medication, or a diagnosed immune condition, review it with your doctor first.
What this page cannot give you
A reference page can take you this far. You know what VIP is and where its research stands, which already puts you ahead of most readers. Four questions remain that no encyclopedia can answer for you, because the answers depend on your own situation:
- What would you measure beforehand, so that later you could tell whether anything actually changed?
- What would you watch along the way, and how consistently?
- What would you ask a professional, and in how much detail, so you do not walk out with a textbook answer?
- What would make you stop?
That is what the course is for
PeptiXtreme is ${CIF.LECCIONES} lessons that hand out no numbers. Each one ends with your starting point, what to watch along the way, the specific questions you take to a professional and the signals that mean stop. It includes per-module exams, a Certificate of Completion with a verifiable certificate ID, a Progress Tracker to follow how you are doing, and a human advisor you can actually write to.
See the course → Or measure your judgment, freeReferences
Every entry links to its record on PubMed, the US National Library of Medicine database. Open them and check. We would rather have a reader who verifies than one who takes our word for it.
- Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA (TESICO): a randomised, placebo-controlled trialhuman Lancet Respir Med · 2023 · PMID 37348524 →
- The Use of IV Vasoactive Intestinal Peptide (Aviptadil) in Patients With Critical COVID-19 Respiratory Failure: Results of a 60-Day Randomized Controlled Trialhuman Crit Care Med · 2022 · PMID 36044317 →
- Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosishuman Am J Respir Crit Care Med · 2010 · PMID 20442436 →
- Aviptadil Therapy in Acute Respiratory Distress Syndrome Patients: A Systematic Review and Meta-analysis Indian J Crit Care Med · 2025 · PMID 41368449 →
- Vasoactive intestinal Peptide inhaled agonists: potential role in respiratory therapeuticsreview Hippokratia · 2013 · PMID 23935337 →
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Frequently asked questions
What is VIP?
Vasoactive intestinal peptide, a natural 28-amino-acid neuropeptide that activates the VPAC1 and VPAC2 receptors and raises cyclic AMP. It relaxes blood vessels and airways, modulates the immune response of the mucosa, and synchronizes the circadian clock. It is studied within the area of immune.
Is there human evidence for VIP?
Synthetic VIP (aviptadil) was tested in randomized, placebo-controlled trials in COVID-19 respiratory failure, which showed no difference in recovery or mortality, and in an open-label inhaled study in 20 people with sarcoidosis, where TNF alpha fell and regulatory T cells in the lung increased. Combined with phentolamine, it has a comparative study against alprostadil in erectile dysfunction.
Is it approved by any health agency?
Not approved by the FDA, which in 2021 declined emergency use authorization in COVID-19; on its list of bulk substances for pharmacy compounding it sits in Category 1, under evaluation (May 2026 update). The combination of aviptadil with phentolamine (Invicorp) is authorized in the United Kingdom and Scandinavia for erectile dysfunction, and India authorized its emergency use in 2022 for severe COVID-19 with respiratory distress. It is not listed by name on the 2026 WADA list.
What is the dose of VIP?
We do not publish dosages. This is not an oversight. No single figure works for everyone: the regimen depends on a person's medical history, on whatever medication they already take, and on the goal they are chasing, which is something a professional weighs with the case in front of them. What you can build is the ability to walk into that appointment knowing what to ask.
Where can I learn to evaluate this properly?
This page tells you what VIP is and what the evidence says. The PeptiXtreme course teaches the other half: what you would measure before considering anything, what you would watch, the specific questions you would take to a professional and when you would stop.