Did it work for COVID?

It was pursued seriously in critical respiratory failure and the trials did not establish benefit convincingly enough for approval. That is a real answer from real trials, and it is worth more than the attention the compound got at the time.

What about mould illness?

Nasal VIP appears late in one clinician's protocol for chronic inflammatory response syndrome. There is no controlled trial of it for that purpose, and the diagnosis is not accepted in mainstream medicine. Both of those things can be true while the symptoms remain real.

Healing & recovery

VIP

Vasoactive intestinal peptide · Aviptadil (synthetic form)

Clinical trialsReviewed 18 Aug 2026

Vasoactive intestinal peptide is a hormone the body produces, found throughout the gut, lungs and nervous system. It relaxes smooth muscle, dilates blood vessels and has broad anti-inflammatory activity. Genuine physiology, characterised since the 1970s.

Its synthetic form, aviptadil, has a real if unsuccessful clinical history. It was studied in pulmonary arterial hypertension, and most visibly in critical COVID-19 respiratory failure, where it was pursued under emergency use consideration. The trials did not establish benefit convincingly and it was not approved.

What people buy it for is different again. Nasal VIP appears in protocols for chronic inflammatory response syndrome, the mould-illness framework, where it is presented as a late-stage treatment. That use rests on one clinician's protocol rather than on trial evidence, and the underlying diagnosis is itself contested in mainstream medicine. Both facts belong on the page.

How it works

VIP binds VPAC1 and VPAC2 receptors, which are widely distributed. Activating them relaxes smooth muscle, dilates blood vessels, and suppresses inflammatory signalling in immune cells.

The vasodilation is why blood pressure falls and flushing occurs. Both are the receptor doing its job, not side effects in the usual sense.

Its anti-inflammatory activity in the lung is why it was pursued in acute respiratory failure, where the problem is inflammatory damage to the alveoli, not the virus itself.

Natural VIP is cleared within minutes, which is the practical obstacle to using it as a drug and the reason clinical work used continuous infusion.

Quick reference

Commonly described dose: 50 mcg
How often: Four times daily
Route: Nasal or Intravenous
Where: Nasal
Timing: Four times daily in the nasal protocols.
Storage once mixed: Refrigerated, 14 days

These describe what sources report, not what you should do. Full detail and provenance in the dosing section below.

Price index

Per-milligram pricing across vendors arrives with the directory. We are recording prices now so the history exists when the page ships.

Vocabulary on this page

Evidence level: The category of human evidence behind a compound, from preclinical through to approved. Stated on every profile here as a category, not an adjective.
Peptide: A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.

The whole glossary →

Regulatory status — United States

Not approved in the United States or the European Union. Synthetic VIP (aviptadil) has been through clinical trials including in critical COVID-19, without establishing benefit sufficient for approval. Nasal preparations sold for chronic inflammatory response syndrome are compounded or research-chemical products with no approval for that use.

Last reviewed 18 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.

What it is studied for

Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.

Critical COVID-19 respiratory failure

Clinical trial

Where the most visible clinical work was.

EvidenceTrials of intravenous aviptadil in critical respiratory failure did not establish benefit convincingly. It was not approved.

Pulmonary arterial hypertension

Clinical trial

An earlier clinical direction.

EvidenceSmall studies of inhaled VIP reported haemodynamic improvement. No registration followed.

Chronic inflammatory response syndrome

Community practice

Why it is bought, and the least evidenced use.

EvidenceDescribed in a single clinician's protocol for mould-related illness. No controlled trial supports it, and the diagnosis itself is not accepted in mainstream medicine.

Identity and clearance

Molecule

Class: Naturally occurring neuropeptide hormone
Molecular weight: 3325.8 Da
Length: 28 amino acids

Dose protocols reported in sources

Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.

Dose protocols reported in sources, with the source of each.
Goal	Dose	Frequency	Route	Units, 1 mg vial	Source	Start this protocol
Commonly described nasal protocol	50 mcg	Four times daily	NasalThe figure that circulates in the mould-illness protocols. It comes from one clinician's published protocol rather than from a dose-ranging study, and the protocol places it after several other steps rather than first.	10 u	Community practice	Start this
Clinical trial administration	100 mcg – 150 mcg	Continuous intravenous infusion over 12 hours	IntravenousThe COVID trials infused it continuously in intensive care, because VIP is cleared within minutes. Nothing about that transfers to a nasal spray at home.	20–30 u	Clinical trial	Start this

Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.

CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.

Safety

Reported effects

Falling blood pressureClinical trial
Expected from the mechanism, documented in trials
VIP is a vasodilator. Hypotension is the receptor working, and it is the effect that required monitoring in the intravenous trials.
Flushing and warmthClinical trial
Common
DiarrhoeaClinical trial
Reported
VIP's original discovery was in the gut, and a tumour that secretes it causes profuse watery diarrhoea. The effect is on-target.
Nasal irritationCommunity practice
Commonly reported with nasal use

When to stop

Dizziness, faintness or light-headedness on standing. That is a blood pressure effect.
Persistent diarrhoea.
Palpitations or chest discomfort.
Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.

Interactions and situations that need care

Low blood pressure, or antihypertensive medicationAvoid
VIP is a vasodilator and lowers blood pressure by design. Adding it to a drug that does the same — or to someone whose pressure is already low — stacks one effect with predictable consequences.
Pregnancy and breastfeedingAvoid
No reproductive or developmental safety data for a hormone with widespread receptor distribution.
Self-administering it intravenouslyAvoid
The clinical work was continuous infusion in intensive care, with blood pressure monitored throughout, because that is what a potent vasodilator requires. Reproducing the route without the monitoring keeps the risk and discards the safeguard.
Treating an undiagnosed chronic illnessUse caution
The symptoms that lead people to the mould-illness framework are real and have many possible causes, several of them diagnosable and treatable. Working through a protocol for a contested diagnosis can mean months not spent finding out what is actually wrong.

What to expect

The physiology is genuine. VIP is a hormone you already produce, characterised since the 1970s.
The clinical trials, including in critical COVID, did not establish benefit and it was not approved.
The mould-illness use rests on one clinician's protocol, not on trial evidence, and the diagnosis itself is contested.
It lowers blood pressure. That is the mechanism, not a side effect, and it is why the trials monitored patients continuously.
The trial route was continuous infusion in intensive care. A nasal spray at home is a different intervention.

Storage and handling

Freeze-dried powder: Refrigerated at 2–8 °C, protected from light.
After mixing: Refrigerated at 2–8 °C. Nasal solutions are handled far more than injectables and are correspondingly easier to contaminate.
Long-term, frozen: Unopened powder is stable at −20 °C or colder.

Printable one-pager How to reconstitute a vial, step by step

Checking your vial

Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it. More on assessing quality and COAs.

White cake, clear solution
Standard for a lyophilised peptide.
Collapsed cake or cloudy solution
Heat damage or degradation. Do not use it.

Questions

Did it work for COVID?: It was pursued seriously in critical respiratory failure and the trials did not establish benefit convincingly enough for approval. That is a real answer from real trials, and it is worth more than the attention the compound got at the time.
What about mould illness?: Nasal VIP appears late in one clinician's protocol for chronic inflammatory response syndrome. There is no controlled trial of it for that purpose, and the diagnosis is not accepted in mainstream medicine. Both of those things can be true while the symptoms remain real.

References

Aviptadil in critical COVID-19 respiratory failure and pulmonary hypertension: clinical programme
Critical care and respiratory medicine literature, 2022 · Randomised controlled trials and earlier small studies
Adults with critical respiratory failure or pulmonary hypertension · Continuous intravenous infusion, or inhaled
Did not establish benefit sufficient for approval in critical COVID-19. Earlier inhaled work in pulmonary hypertension reported haemodynamic improvement without leading to registration. Hypotension and flushing were consistent with the compound's vasodilator mechanism.
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Records dose and route patterns described in public discussion. Carries no evidential weight about safety or effect.

Related compounds

BPC-157

A synthetic 15-amino-acid peptide studied in animals for effects on tendon, ligament and gut tissue repair. No completed human trials.

TB-500

A synthetic fragment of thymosin beta-4, a naturally occurring protein involved in cell migration and tissue repair. Animal evidence only.

GHK-Cu

A naturally occurring copper-binding tripeptide with a long history in topical skincare research. Injected use is not what the research studied.

KPV

A three-amino-acid fragment of alpha-MSH studied for anti-inflammatory effects, largely in animal models of gut inflammation.

Keep this page honest

If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.

Suggest a correction

This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.

Page last updated 18 Aug 2026