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No. 034 · Mind · Neuropeptide

VIP

AviptadilVasoactive intestinal polypeptideRLF-100Zyesami

A Tier A · Controlled human trials how tiers work →
  • Not FDA approved
  • WADA — not listed
Compare Cite
Fingerprint 28 residues
VIP sequence fingerprint
  • Nonpolar 10
  • Polar 10
  • Positive charge 6
  • Negative charge 2

Each dot is a residue placed around the ring from N- to C-terminus; its distance from the centre reflects its chemistry.

01

Evidence

  1. D In vitro
  2. C Animal
  3. B Human pilot
  4. A RCT
  5. S Approved

TIER A — At least one published randomized controlled trial in humans.

Randomized placebo-controlled trials of aviptadil exist (erectile dysfunction with phentolamine, 1999; COVID-19 respiratory failure, TESICO 2023); nationally authorised in some European countries but not FDA- or centrally EMA-approved.

Tiers rate the strength of published evidence — not effectiveness, safety, or a recommendation.

02

At a glance

Residues
28 amino acids, N→C
Molecular weight
3,325.8 Da
Formula
C147H238N44O42S
Discovered
1970 Isolated from porcine small intestine by Said and Mutt (Science 1970).
Routes studied
Intranasal, Subcutaneous Routes used in published research
FDA
Not approved Intravenous aviptadil (RLF-100/Zyesami) was studied for COVID-19 respiratory failure but not approved.
Other approvals
  • Invicorp (aviptadil + phentolamine) for erectile dysfunction — nationally authorised in several European countries; first approval Denmark (1998)
WADA
Not on the Prohibited List
03

Sequence

N → C · 28 residues · hover, tap, or use arrow keys to inspect

04

Overview

Vasoactive intestinal peptide is a 28-amino-acid neuropeptide involved in circadian rhythm regulation, immune modulation, and smooth-muscle relaxation. As aviptadil it has been tested in randomized trials, and intranasal VIP is used in some chronic inflammatory response syndrome (CIRS) protocols without controlled-trial support.

Research status Aviptadil tested in RCTs (erectile dysfunction with phentolamine; COVID-19 respiratory failure, where TESICO found no benefit); small open-label pulmonary hypertension studies; no PubMed-indexed controlled trials for CIRS

05

Mechanism

VIP binds VPAC1 and VPAC2 G-protein-coupled receptors, activating adenylyl cyclase and increasing intracellular cAMP. In immune cells this suppresses pro-inflammatory cytokine production (TNF-alpha, IL-6) and promotes regulatory T-cell differentiation. In the brain it serves as a key circadian clock synchronizer in the suprachiasmatic nucleus.

06

Effects reported in research

Reported outcomes, not promises. Some come from controlled human trials; others may be from smaller or preclinical studies — check the studies below.

  • Regulation of circadian rhythms
  • Anti-inflammatory immune modulation
  • Vasodilation and smooth-muscle relaxation
  • Pulmonary vasodilation (small open-label pulmonary hypertension studies)
07

Safety & unknowns

Endogenous neuropeptide with established physiology. Intranasal use in CIRS protocols comes from uncontrolled clinical reports. Side effects may include nasal irritation, transient diarrhea, and hypotension. Not FDA-approved for any indication; aviptadil with phentolamine (Invicorp) is nationally authorised for erectile dysfunction in some European countries.

Unknowns. Trial safety data apply to the populations, formulations and conditions studied.

Informational only — not medical advice. peptidemeta publishes no dosing, protocols, or sourcing. Talk to a qualified clinician about any treatment decision.

08

Studies [1]

  1. Clinical trial 2023

    Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA (TESICO): a randomised, placebo-controlled trial

    Brown SM, Barkauskas CE, Grund B, et al. The Lancet Respiratory Medicine

    In 461 patients with COVID-19-associated acute hypoxaemic respiratory failure, intravenous aviptadil did not significantly improve clinical outcomes at day 90 compared with placebo.

    [pubmed] [doi]

10

Status sources

Sources behind the tier, regulatory status, sequence and dates on this page.

11

Cite this entry

$ cite --format=apa

peptidemeta. (2026). VIP. In peptidemeta: The peptide library, ranked by evidence. Retrieved November 8, 2026, from https://peptidemeta.com/p/vip/

$ cite --format=bibtex 
@misc{peptidemeta-vip,
  title = {VIP},
  author = {{peptidemeta}},
  year = {2026},
  howpublished = {\url{https://peptidemeta.com/p/vip/}},
  note = {Accessed 2026-11-08}
}

Accessed date reflects when you opened this page. Cite primary studies for scientific claims.

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