Vasoactive Intestinal Peptide
Also called VIP, aviptadil
Vasoactive Intestinal Peptide is a signalling molecule your body uses in the gut, the lungs, the immune system and the brain's master clock.
Studied in people, in small numbers. The ranges below lean mostly on community-reported dosing and results — what people run, and what they say happened.
- Immune
- Nerve comfort
The quick answer
Vasoactive Intestinal Peptide is a signalling molecule your body uses in the gut, the lungs, the immune system and the brain's master clock. It was named for the first thing anyone noticed it doing, which undersells it considerably. Most people meet it through mould-illness and chronic-inflammation protocols.
What it is not
Not a stimulant and not a nootropic in the ordinary sense. The cognitive reports come out of inflammation coming down.
Why people use it
🌬️ Reported easier breathing and less chest tightness; 🧠 Brain fog lifting is the signature report; 😴 Sleep and daily rhythm; 🔥 A broad anti-inflammatory signal rather than a targeted one
What people report using
These are ranges other people have reported running. They are here so you can see what has actually been done — they are not medical advice and not a recommendation for you.
- How often
- Four times daily
- Route
- intranasal
- Evidence for this
- Small human studies
The published work describes gradual improvement over several months.
What to expect, and when
Week 1: flushing and blood-pressure awareness; earliest breathing reports. Week 2-6: fog and sleep. Protocols in those communities run for months.
Side effects, and what people do about them
Flushing and a drop in blood pressure are the two to know, since it is a vasodilator - people report lightheadedness on standing in the first week. Loose stools. Nasal irritation with the spray.
Go deeper
Open these only if you want them.
How it actually works
A 28-amino-acid peptide acting at VPAC1 and VPAC2 receptors. Broadly anti-inflammatory, a pulmonary vasodilator, and a key transmitter in the suprachiasmatic nucleus - the body's clock - which is why sleep and rhythm effects come up alongside the inflammatory ones.
More on the evidence
Aviptadil has been trialled in humans; the nasal use people describe has not.
The case against
The human work is small and mostly in pulmonary hypertension and sarcoidosis rather than in the use it has actually found. Encouraging, and narrow.
What people report, in full
Almost all the community experience with VIP comes from one place: the chronic inflammatory response and mould-illness communities, where it is used as a late step after other things have been dealt with. That context matters, because the reports come from people who had already been unwell a long time, and they describe it in those terms - fog lifting, breathing easier, sleep finally normalising. It is nearly always the nasal spray rather than an injection. The most repeated practical point in those communities is about sequence: people who reached for it before addressing their exposure report it doing nothing, while the strongest reports come from people who did the rest first. Blood pressure is the second theme - it is a vasodilator, and people describe standing up carefully early on.
Sources and review
https://pubmed.ncbi.nlm.nih.gov/36044317/
https://pubmed.ncbi.nlm.nih.gov/37348524/
https://pubmed.ncbi.nlm.nih.gov/20442436/
Last reviewed 2026-09-08.
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Ask it the way you would ask a person. Follow-up questions are the point — it remembers what you already said.
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