What it actually is
Limitless Biotech
VIP, Vasoactive Intestinal Peptide (5mg)
Vasoactive intestinal peptide is a 28-amino-acid neuropeptide found throughout the body, first isolated from intestine, hence the name. It acts on vascular tone, smooth muscle relaxation, immune signalling and inflammatory regulation.
It is a genuine endogenous signalling molecule with a substantial physiology literature, which already puts it ahead of several compounds in this catalogue on basic science.
Of the vendors we review, Limitless Biotech stocks it at 5mg.
Why interest tripled
At 9,900 searches a month and up 311% year on year, VIP is rising faster than anything else we measured, including the compounds with far more marketing behind them. That is worth explaining rather than just noting.
The driver is not the clinical literature. It is CIRS, chronic inflammatory response syndrome, a framework associated with mould and biotoxin exposure. VIP nasal spray appears as a late step in protocols built around that framework.
Worth being straight about the status of that: CIRS is not a widely accepted diagnosis in mainstream medicine, and the protocols around it sit outside standard practice. We are describing where the demand comes from, not endorsing the framework that generates it.
The practical consequence is that most people searching VIP peptide are not looking for the pulmonary hypertension literature. They have arrived from a protocol.
What the clinical work covers
Separating the two strands, because they barely overlap.
| Context | Status | Relevance to a research vial | Buy |
|---|---|---|---|
| Pulmonary arterial hypertension | Studied clinically, inhaled formulations trialled | Specific disease, specialist setting | |
| Inflammatory and autoimmune signalling | Substantial physiology literature | Mechanistic, not an intervention protocol | |
| CIRS protocols | Outside mainstream practice; drives most search demand | This is what buyers are following | Shop |
| General wellbeing or energy | No evidence | Appears in marketing |
Two different VIP conversations
The nasal route question
CIRS protocols specify VIP as a nasal spray, and this is where the pharmacology deserves a harder look than it usually gets.
28 amino acids is large for nasal absorption. The nasal route works well for small molecules and for peptides specifically engineered with absorption enhancers. A 28-residue peptide without a disclosed enhancer is a different proposition, and the fraction reaching circulation is not something we could find published for this compound.
Compounded nasal VIP from a pharmacy is formulated for that route. A lyophilised research vial is not, and reconstituting one into a nasal applicator is not the same product.
So if a protocol specifies nasal VIP, the vial being sold is not obviously the thing the protocol describes. That is worth knowing before buying one.
The dosing figures
From circulating protocols rather than dose-finding trials, as everywhere else in this field.
CIRS protocols typically describe 50mcg per spray, four times daily, which works out at roughly 200mcg a day. On that basis a 5mg vial is around 25 days.
Injected protocols are less consistent, which makes sense given the primary use case is nasal. Our calculator converts whichever figure into syringe units if you are working with a vial.
What we would say to someone arriving from a protocol
The compound is real, the physiology is real, and the clinical literature is about something other than why you are here. None of that makes a protocol wrong, and none of it makes it evidenced.
Two concrete things. A research vial is not a compounded nasal formulation, so you are not buying the thing the protocol names. And Limitless gates every price behind an approved research account, which our pricing page covers, so you cannot compare cost before registering.
Our are peptides safe page covers the risk picture. Everything referenced is sold for research use, nothing here is medical advice, and a suspected biotoxin illness is a reason to see a clinician rather than a reason to buy a vial.
