LTP·01learntopeptide
Cognitive & neuroPeptideEvidence B3 cited

VIP

Vasoactive Intestinal Peptide

aka Vasoactive Intestinal Peptide · vasoactive intestinal polypeptide · PHM-27

A 28-amino acid regulatory peptide researched for immune modulation, circadian rhythm, and neuroprotection.

Molecular wt
3326.8g/mol
Formula
C147H237N43O43S
CAS
37221-79-7
Half-life
1 h
clinical
Tmax
30 min
Route
Subcutaneous injection
PubChem
16132300

Sequence

One-letter28 residues

HSDAVFTDNYTRLRKQMAVKKYLNSILN

Three-letter

His-Ser-Asp-Ala-Val-Phe-Thr-Asp-Asn-Tyr-Thr-Arg-Leu-Arg-Lys-Gln-Met-Ala-Val-Lys-Lys-Tyr-Leu-Asn-Ser-Ile-Leu-Asn-NH2

Read this before quoting the sequence
28 residues, C-terminally amidated (UniProt P01282 records 'Asparagine amide' at position 152, the last residue of the mature VIP peptide 125-152). The synthetic form has INN aviptadil. Human and porcine VIP are identical in sequence. IMPORTANT: 'PHM-27' is listed as an alias in the ported data but is a DIFFERENT peptide - PHM-27 is residues 81-107 of the same precursor, sequence HADGVFTSDFSKLLGQLSAKKYLESLM-NH2.
Source ↗

Mechanism of action

Vasoactive intestinal peptide (VIP) works by binding to specific receptors on cell surfaces, leading to the activation of adenylate cyclase and increased cyclic AMP levels. This cascade results in smooth muscle relaxation, vasodilation, and modulation of immune responses. VIP also influences circadian rhythms by acting on the suprachiasmatic nucleus in the brain.

What the evidence actually shows

Grade B

There are a limited number of human trials investigating VIP, primarily focusing on its effects in CIRS and neuroprotection. These studies suggest potential benefits, but larger, more comprehensive trials are needed to confirm efficacy and safety. Current gaps include long-term safety data and broader population studies.

Regulatory status

Status
Not approved. Aviptadil (synthetic VIP) has no FDA approval - no Drugs@FDA record and no DailyMed SPL - and a UK emc search returns no licensed aviptadil-containing medicine.
Clinical stage
Phase 3 completed and negative. ClinicalTrials.gov lists 9 aviptadil studies (5 phase 3, 5 phase 2); the definitive phase 3 TESICO trial did not meet its primary endpoint.
WADA
Not named on the WADA 2026 Prohibited List.
UK
research_compound

In the UK, VIP is considered a research compound and is not approved for clinical use outside of research settings.

Source ↗

Pharmacokinetics

Half-life
1 h
Tmax
30 min
Absorption
subcutaneous
Elimination
renal
Washout
1 days
Low-confidence pharmacokinetics
These figures are recorded as clinical rather than measured in a published PK study. Treat them as an order of magnitude. Anything downstream of them — accumulation, steady state, washout — inherits that uncertainty.

Dosing — what backs each figure

VIP (aviptadil) has genuine documented human dosing, but not by the nasal route: 25 micrograms intracavernosally with phentolamine under a UK marketing authorisation (Invicorp), and 600-1800 pmol/kg/day as a 12-hour intravenous infusion for 3 days in the TESICO COVID trial. Intranasal VIP has no published dosing study.

ClinicalApproved labelling or a published human trial
Commonly circulatedNot established by any study
Dose
50-100 mcg/dose (nasal)
Frequency
1-2x daily

Why this isn't evidence
No published human trial of intranasal VIP at any dose was found; the microgram-per-spray nasal regimen originates from compounded-pharmacy CIRS/mould-illness practice, and every documented human VIP route is instead intracavernosal (25 microgram label dose), intravenous (pmol/kg infusion) or nebulised.

This figure is shown because it is what circulates and what people search for — not because it is supported. Cycle lengths in particular tend to be convention copied between compounds rather than anything derived from a compound's own pharmacokinetics.

Handling and storage

No compound-specific stability data exists
No approved product label could be retrieved. Aviptadil has no FDA approval (absent from Drugs@FDA and DailyMed) and a UK emc search for aviptadil returns no licensed medicine. No compound-specific stability data located in indexed literature. Ported storage text ('-20C ~24 months lyophilised; 2-8C ~4 weeks reconstituted') is generic peptide-handling boilerplate that was applied identically across many compounds in this dataset. It is not sourced to this compound. General peptide handling still applies — reconstitute gently, keep it cold, keep it dark — but any specific figure you see quoted for this compound elsewhere is someone's assumption, not a measurement.
→ Reconstitution walkthrough→ Reconstitution calculator

Safety

Commonly reported
  • ·Headache
  • ·Nausea
  • ·Flushing
Rarely reported
  • ·Severe allergic reactions
  • ·Hypotension
Contraindications
  • ·Hypersensitivity to VIP or any component of the formulation
Drug interactions
  • ·Beta-blockers: May reduce the vasodilatory effects of VIP

Reported combinations

Reported as synergistic
  • ·Melatonin: May enhance circadian rhythm regulation
Reported as antagonistic
  • ·Corticosteroids: May counteract immune modulation effects

Combination claims in this dataset are largely unsourced and should be treated as folk knowledge until a citation appears beside them.

References (3)

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
storage.lyophilized, storage.reconstituted, storage.lightSensitive, reconstitution.solvent, molecularFormula (amidated form)

Research use only
This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

Related in Cognitive & neuro

ARA-290
An 11-amino acid peptide derived from erythropoietin (EPO) that activates the innate repair receptor (IRR) without stimulating erythropoiesis. Provides neuroprotection, anti-inflammatory, and tissue repair effects.
CAQK
Brain-injury-homing tetrapeptide targeting chondroitin sulfate proteoglycans at injury sites.
Cerebrolysin
A porcine-derived neuropeptide complex researched for neuroprotection, cognitive recovery, and stroke rehabilitation.