---
title: "VIP: what sources report"
url: https://humanpeptides.fyi/peptides/vip
site: humanpeptides.fyi
last_reviewed: 2026-10-11
---


# VIP

> humanpeptides.fyi makes no claims of its own. Every statement below reports what a cited source says, with its link. Not medical advice.

VIP: Endogenous 28-amino-acid neuropeptide acting on VPAC1/VPAC2 receptors that regulates vasodilation, gut secretion, immunity and circadian rhythm. The sources cited here most often discuss it for: Immune balance, small studies; Erectile function, approved abroad; Mold-related illness, small studies. Evidence label: Early human.

## At a glance

- **Type:** Peptide
- **Family:** Immune & Gut
- **Evidence label:** Early human (3 of 5)
- **Regulatory status:** In 2022 FDA declined emergency use authorization for aviptadil (Zyesami), a synthetic form of VIP, for COVID-19 respiratory failure.
- **Goals discussed:** Immunity, Libido & Sexual Health
- **Also called:** aviptadil, vasoactive intestinal polypeptide, Invicorp, Zyesami, RLF-100, VIP spray
- **Last reviewed:** 2026-10-11

## What is VIP?

- Endogenous 28-amino-acid neuropeptide acting on VPAC1/VPAC2 receptors that regulates vasodilation, gut secretion, immunity and circadian rhythm; synthetic form is aviptadil - not FDA-approved in US (failed COVID trials); approved in UK/EU combined with phentolamine (Invicorp) for erectile dysfunction. Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC6743256/>, <https://bnf.nice.org.uk/drugs/aviptadil-with-phentolamine-mesilate/>

**Regulatory status:** In 2022 FDA declined emergency use authorization for aviptadil (Zyesami), a synthetic form of VIP, for COVID-19 respiratory failure. Source: <https://www.managedhealthcareexecutive.com/view/fda-declines-eua-request-for-zyesami-for-covid-19>

## What is VIP researched for?

### 1. Immune balance, small studies

- Anti-inflammatory/immune modulation: VIP suppresses pro-inflammatory pathways, favoring Th2/Treg responses; inhaled VIP in 20 sarcoidosis patients reduced lung TNF-alpha and increased regulatory T cells (review + small open human phase 2) Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC6982157/>, <https://www.ovid.com/20442436.pmid>
- Goals: [Immunity](https://humanpeptides.fyi/objectives/immunity)

### 2. Erectile function, approved abroad

- Erectile dysfunction: aviptadil/phentolamine intracavernosal injection (Invicorp) approved in UK for men failing oral therapy; 187-man crossover vs alprostadil showed less pain/fewer adverse events (human trial, approved drug) Sources: <https://scottishmedicines.org.uk/medicines-advice/aviptadilphentolamine-mesilate-invicorp-fullsubmission-128417/>, <https://scottishmedicines.org.uk/media/3091/aviptadil_phentolamine_mesilate_invicorp_final_nov_2017_for_website.pdf>
- Goals: [Libido & Sexual Health](https://humanpeptides.fyi/objectives/libido)

### 3. Mold-related illness, small studies

- Mold-related illness (CIRS): open-label study of 20 refractory patients on intranasal VIP reported symptom and inflammatory-marker improvement (uncontrolled, single practitioner group)
- COVID respiratory failure: IV aviptadil failed primary endpoints; phase 3 TESICO stopped for futility (human RCTs, negative)
- Sources for this benefit: <https://scirp.org/html/6-8202013_28586.htm>, <https://pmc.ncbi.nlm.nih.gov/articles/PMC9555831/>, <https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(23>
- Goals: [Immunity](https://humanpeptides.fyi/objectives/immunity)

## What do researchers and users say about VIP?

> "Among patients with COVID-19-associated acute hypoxaemic respiratory failure, aviptadil did not significantly improve clinical outcomes up to day 90 when compared with placebo."
>
> Brown SM, et al. (TESICO investigators), Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA (TESICO): a randomised, placebo-controlled trial (Lancet Respiratory Medicine, 2023). <https://scholars.duke.edu/publication/1586353>

Context: Placebo-controlled trial of intravenous aviptadil in 461 hospitalised adults with COVID-19 respiratory failure; stopped early for futility.

> "We might never understand why vasoactive intestinal peptide initially looked promising but was ultimately found to not have a significant effect, an unfortunately too common fate for interventions in critical care."
>
> Lee WL, Slutsky AS, A negative trial for vasoactive intestinal peptide in COVID-19-associated acute hypoxaemic respiratory failure (Lancet Respiratory Medicine, 2023). <https://pmc.ncbi.nlm.nih.gov/articles/PMC10278994/>

Context: Editorial commentary on the TESICO trial results.

> "It wasn't until VIP that I felt like I'm starting to live."
>
> Anonymous user, r/CIRS, Over a month on VIP. <https://www.reddit.com/r/CIRS/comments/1vz4idf/over_a_month_on_vip/>

Context: Self-report from someone with chronic inflammatory response syndrome (CIRS), POTS and chronic fatigue using nasal VIP under a practitioner; uncontrolled anecdote, and brain fog temporarily worsened.

## What side effects of VIP are reported?

- Excess VIP (as in VIP-secreting tumors) causes severe watery diarrhea and electrolyte loss, illustrating dose-related risk Sources: <https://bpgweb.azurewebsites.net/1948-5204/full/v14/i4/808.htm>
- Intracavernosal use has fewer moderate/severe AEs than alprostadil Sources: <https://scottishmedicines.org.uk/media/3091/aviptadil_phentolamine_mesilate_invicorp_final_nov_2017_for_website.pdf>
- Intranasal CIRS study reported no significant adverse effects Sources: <https://scirp.org/html/6-8202013_28586.htm>
- Significant lowering of blood pressure, with more vasopressor use afterwards, in the large intravenous COVID-19 trial. (human RCT) Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC10278994/>
- With the UK erectile dysfunction injection, flushing and bruising are common; dizziness, headache, palpitations and fast heart rate are uncommon; angina and heart attack are rare. (UK drug label (BNF)) Sources: <https://bnf.nice.org.uk/drugs/aviptadil-with-phentolamine-mesilate/>
- PepEdHub lists nasal congestion, diarrhea and flushing with nasal use, and treats active cancer as a contraindication because of possible blood-vessel growth effects. (practitioner resource) Sources: <https://pepedhub.com/peptides/vip>
- Faintness from low blood pressure, plus irritability and anxiety in the first days, reported by users of nasal VIP. (anecdotal) Sources: <https://www.reddit.com/r/CIRS/comments/1728jjn/finally_starting_vip/>

## What do peptide guides say about VIP?

- **PepEdHub:** PepEdHub describes VIP as a 28-amino-acid neuropeptide central to the Shoemaker protocol for CIRS (mold illness), claiming it lowers inflammatory cytokines and restores regulatory T-cell function. <https://pepedhub.com/peptides/vip>
- **NCBI PMC:** A 2025 critical-care editorial notes pooled data from two randomized trials showed no survival benefit for aviptadil in respiratory distress, even though oxygenation improved consistently. <https://pmc.ncbi.nlm.nih.gov/articles/PMC12683538/>
- **NCBI PMC:** Commentators note the large US trial recorded significant blood pressure lowering and more vasopressor use with aviptadil, which may have masked any benefit. <https://pmc.ncbi.nlm.nih.gov/articles/PMC10278994/>
- **BNF (NICE):** In the UK, aviptadil combined with phentolamine (Invicorp) is a licensed injection for erectile dysfunction, with aviptadil acting as a smooth muscle relaxant. <https://bnf.nice.org.uk/drugs/aviptadil-with-phentolamine-mesilate/>

## What does the research say, system by system?

### Body & tissues

- Gut (chloride/bicarbonate secretion, motility, barrier), blood vessels (vasodilation), lungs, erectile tissue Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC6743256/>, <https://bnf.nice.org.uk/drugs/aviptadil-with-phentolamine-mesilate/>

### Hormones & physiology

- Immune cells produce VIP, which dampens inflammation; aviptadil showed early oxygenation/cytokine effects in COVID (human RCT secondary) Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC6982157/>, <https://pubmed.ncbi.nlm.nih.gov/36044317/>

### Cells & mitochondria

- RNA-seq in VIP-treated CIRS patients suggested shift in metabolic state and innate immune function (small observational) Sources: <https://scispace.com/papers/rna-seq-on-patients-with-chronic-inflammatory-response-3nz7a3x242>

### Brain, mood & sleep

- VIP synchronizes the suprachiasmatic nucleus circadian clock; loss of VIP/VPAC2 disrupts rhythms (animal) Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC6358603/>, <https://pmc.ncbi.nlm.nih.gov/articles/PMC3942163/>

### Also notable

- VIP-secreting tumors (VIPomas) cause severe watery diarrhea, low potassium (WDHA), illustrating effects of excess VIP Sources: <https://bpgweb.azurewebsites.net/1948-5204/full/v14/i4/808.htm>
- Improved 60-day survival signal in one COVID trial not confirmed in phase 3 Sources: <https://pmc.ncbi.nlm.nih.gov/articles/PMC9555831/>

## How strong is the evidence for VIP?

**Early human** (3 of 5). Approved abroad for ED (combo); human RCTs negative for COVID; small/uncontrolled studies for sarcoidosis and CIRS

_Small, short, old, unblinded or single-group human studies._

## Questions about VIP

### What is VIP?

Endogenous 28-amino-acid neuropeptide acting on VPAC1/VPAC2 receptors that regulates vasodilation, gut secretion, immunity and circadian rhythm.

### Is VIP FDA-approved?

In 2022 FDA declined emergency use authorization for aviptadil (Zyesami), a synthetic form of VIP, for COVID-19 respiratory failure.

### What is VIP researched for?

The sources cited on this page most often discuss three outcomes: Immune balance, small studies; Erectile function, approved abroad; Mold-related illness, small studies. Each line above shows what the source reports and how strong that evidence is.

### What side effects of VIP are reported?

Reported in the cited sources: Excess VIP (as in VIP-secreting tumors) causes severe watery diarrhea and electrolyte loss, illustrating dose-related risk; Intracavernosal use has fewer moderate/severe AEs than alprostadil; Intranasal CIRS study reported no significant adverse effects. The list is not complete, and few listed risks does not mean a compound is safe.

### How strong is the evidence for VIP?

Evidence label: Early human. Approved abroad for ED (combo); human RCTs negative for COVID; small/uncontrolled studies for sarcoidosis and CIRS.

### What else is VIP called?

Names used for it include aviptadil, vasoactive intestinal polypeptide, Invicorp, Zyesami, RLF-100, VIP spray.

### Does humanpeptides.fyi recommend VIP?

No. humanpeptides.fyi makes no claims and no recommendations of its own. It summarizes and links to what others have published and posted. Nothing here is medical advice; talk to a licensed clinician.

---
Family: [Immune & Gut](https://humanpeptides.fyi/peptides?cat=immune). HTML version: <https://humanpeptides.fyi/peptides/vip>. Disclaimer: <https://humanpeptides.fyi/disclaimer>