VIP

Immune Approved · Some countries Human trials

Also called Vasoactive intestinal peptide, Aviptadil (synthetic form)

A 28-amino-acid signaling peptide made in the gut, pancreas and brain. It relaxes smooth muscle, widens blood vessels and airways, drives fluid secretion in the intestine, calms inflammation and helps set the body clock. Its half-life in blood is only about a minute.

Evidence at a glance

Evidence: Human trials — Studied in people
Status: An approved medicine in Some countries
Dosing: A dose has been tested in humans

Its one-minute half-life in blood makes practical use difficult. COVID-era aviptadil trials were widely criticised.

What studies report

Relaxes airways and blood vessels, reduces inflammation
Trialed as aviptadil for respiratory failure, with contested results
Part of an approved injection for erectile dysfunction in some countries

How it works

Acts on class II G protein-coupled receptors across the gut, lungs and brain — relaxing smooth muscle, widening vessels and airways, calming inflammation, and helping synchronise the body clock in the suprachiasmatic nucleus.

Binds a receptor on the cell surface and signals inward

Where it acts

Thymus

The library groups this compound under Immune. The diagram shows that target, not every tissue it reaches.

Illustrated

Small intestine wall cutaway with circular smooth muscle, mucosa and a few enteric nerve fibres.

AI-generated subject illustration; not a depiction of the compound or evidence of its effects.

Why people take it

Airway and lung inflammationChronic inflammatory conditionsCircadian rhythm

Reasons people seek it out — not a list of proven effects.

In practice Off-label

Used nasally in the mold-illness and CIRS community, following the Shoemaker protocol
Typically a late step after other protocol stages

Science hasn't caught up: A defined patient community uses this on a specific protocol that mainstream medicine does not recognise.

Reported real-world use, not evidence and not a recommendation.

Dosing

What was tested Evidence

50 mcg intranasal, four times dailyUsed within the Shoemaker CIRS protocol→ Reported symptom improvement; not from controlled trials

What people report using Not evidence

Follows the protocol's schedule rather than a community-derived range

Mainstream medicine does not recognise this protocol.

Reported for reference, not as instruction. Nothing here is a recommendation to take anything, and most of these compounds are not approved for human use.

Status: Synthetic VIP (aviptadil) has been trialed for lung conditions and is approved in some countries in a combination product for erectile dysfunction.

Route: Intranasal spray, following the protocols it is used under
Sequence: HSDAVFTDNYTRLRKQMAVKKYLNSILN-NH2
Formula: C147H238N44O42S
Molecular weight: 3325.8 g/mol
CAS: 40077-57-4
Available as: 2 mg, 10 mg

Search PubMed for VIP → We link a live search rather than a fixed citation list, so it stays current and nothing here is a reference we have not checked.

Educational information only. Nothing here is medical advice, a dosing protocol, or a recommendation to use any compound. Most entries describe substances not approved for human use. Talk to a licensed clinician before acting on anything you read here. How to read these entries.