Guides May 11, 2026

VIP Peptide FDA Status: Category 1, CIRS Use, and a Long Compounding History

VIP peptide, or vasoactive intestinal peptide, has a real clinical literature, a controversial role in the Shoemaker CIRS protocol, and an unusual FDA Category 1 compounding status in 2026.

VIP has one of the strangest regulatory stories in the peptide world.

It has:

a real endogenous biology
a small but legitimate human clinical literature
a controversial off-label role in the Shoemaker CIRS protocol
and an FDA compounding history that is easy to get wrong if you only follow the current peptide headlines

That last point matters.

A lot of people assume every clinically used peptide fits neatly into one of three buckets:

FDA approved
on the current PCAC peptide cycle
or effectively pushed out of compounding

VIP does not fit cleanly into any of them.

What VIP is

VIP stands for vasoactive intestinal peptide.

It was first isolated from porcine small intestine in 1970 by Sami Said and Viktor Mutt.¹

The original Science paper described it as a polypeptide with broad biological activity and identified it as a 28-amino-acid peptide.¹

Despite the name, VIP is not just an intestinal signaling molecule.

Later receptor and pharmacology reviews describe VIP as a widely distributed neuropeptide with actions across:

the gastrointestinal tract
the lungs
the cardiovascular system
the immune system
and the central nervous system²³

The receptor story is also important.

VIP and PACAP act through three class-B GPCRs:

VPAC1
VPAC2
PAC1

but VPAC1 and VPAC2 are the main receptors that respond to both VIP and PACAP with high affinity, while PAC1 is more selective for PACAP.²

That is why VIP gets described as:

a vasodilator
a bronchodilator
a neuropeptide
and an immune modulator

all at the same time.

The cleanest human clinical signal: sarcoidosis

The strongest conventional clinical paper behind VIP is not from CIRS.

It is the 2010 sarcoidosis study in the American Journal of Respiratory and Critical Care Medicine.⁴

That study evaluated inhaled VIP in 20 patients with sarcoidosis.

The authors reported that inhaled VIP produced immunoregulatory effects in the pulmonary compartment, including a reduction in TNF-alpha production by bronchoalveolar lavage cells.⁴

That is not a large phase 3 program.

But it is real human interventional evidence published in a mainstream respiratory journal.

That already puts VIP in a different category than many peptides that circulate almost entirely on theory or anecdote.

Where VIP became a clinical niche product: the Shoemaker CIRS protocol

The place VIP gained the most sustained real-world use was not sarcoidosis.

It was the Shoemaker protocol for chronic inflammatory response syndrome (CIRS), especially in the context of water-damaged-building exposure.

This is the part of the story where the evidence base becomes much more controversial.

The key published papers are mostly from the same research / clinical network:

a 2013 open-label VIP paper in Health⁵
a 2016 RNA-seq paper in Medical Research Archives⁶
later gray-matter / transcriptomic follow-up work in less mainstream publication venues⁷⁸

The 2013 paper is the one most often cited as the starting point for intranasal VIP use in CIRS.

It reported on 20 patients with refractory CIRS associated with water-damaged buildings who self-administered 50 mcg VIP nasal spray four times per day and were followed over time.⁵

The paper described improvements in symptoms and multiple biomarkers in that small cohort.⁵

The problem is not that nothing was published.

The problem is that:

the studies are small
the designs are not randomized controlled trials
and most of the literature comes from a single clinical ecosystem rather than broad independent replication

That is why VIP in CIRS still sits in a gray zone:

clearly more than pure internet lore
but also not close to mainstream clinical validation

What about the “10,000 patients” claim?

This is one of the most repeated numbers in the VIP conversation.

The Surviving Mold advocacy materials around VIP state that since first use in nasal-spray form in 2008, VIP has been used in over 10,000 patients, and they frame that as evidence of both access needs and safety experience.⁹

That is important context, but it needs to be described honestly.

As far as we found, that 10,000+ figure is best understood as a practice-community / advocacy claim, not as the result of a large published multicenter registry in the conventional drug-development sense.

So the fairest version is:

there is a substantial real-world CIRS practice claim around VIP use
but the highest-quality published evidence remains far smaller than the number suggests

That distinction matters a lot.

The FDA history is older and more complicated than most people realize

VIP did not suddenly become relevant in 2026.

Its FDA compounding history goes back years.

2016: PCAC review

In FDA’s November 3, 2016 briefing document for the Pharmacy Compounding Advisory Committee, VIP appeared as one of the substances nominated for inclusion on the 503A bulks list.¹⁰

That document is explicit that FDA was proposing not to include VIP on the 503A bulks list at that time:

FDA is proposing that vasoactive intestinal peptide NOT be included on the 503A Bulks List.¹⁰

So VIP’s compounding fight predates the current peptide wave by almost a decade.

2019: proposed federal rule

FDA’s September 2019 proposed rule on amendments to the 503A bulks list again identified VIP among the substances the agency proposed not to place on the list.¹¹

That is the formal source behind a lot of the “FDA tried to restrict VIP” language that still circulates today.

2026: the part most people miss

Here is the twist.

As of the FDA’s Updated April 22, 2026 PDF for bulk drug substances nominated for use in compounding under section 503A, Vasoactive Intestinal Peptide appears in 503A Category 1 – Bulk Drug Substances Under Evaluation.¹²

That matters because FDA’s own 503A page explains that substances in Category 1 are under evaluation and that FDA does not intend to take action against a compounder for using those substances, provided the conditions in the guidance are met.¹³

So the cleanest current regulatory summary is not:

VIP is outside FDA review

It is:

VIP has already been through FDA compounding review history, was proposed against in 2016 and 2019, and as of April 2026 is still sitting in 503A Category 1 under evaluation.

That is a much more unusual status than either “fully cleared” or “fully banned.”

Why VIP is still a regulatory outlier in 2026

Even though VIP is in Category 1, it is also notably absent from the currently published peptide-heavy PCAC agendas.

FDA’s July 23-24, 2026 PCAC meeting is set to discuss:

BPC-157-related substances
KPV-related substances
TB-500-related substances
MOTs-C-related substances
emideltide / DSIP-related substances
Semax-related substances
Epitalon-related substances¹⁴

VIP is not on that list.

And FDA’s early announcement for the meeting before the end of February 2027 names:

LL-37
GHK-Cu
Dihexa acetate
Melanotan II
PEG-MGF¹⁵

VIP is not on that list either.

That is what actually makes VIP unusual right now.

It is not that the FDA has never touched it.

It is that:

FDA touched it years ago
VIP remains in Category 1 under evaluation
and yet it is not part of the currently published 2026–2027 peptide agenda cycle

That is a very different story than the usual “currently under active PCAC review” compounds.

The practical takeaway

If you want the shortest honest version:

VIP is a real 28-amino-acid endogenous neuropeptide
it has real receptor biology through VPAC1 and VPAC2
it has a small but legitimate human interventional literature, especially in sarcoidosis
it also has a controversial but persistent role in the Shoemaker CIRS protocol
the CIRS evidence base is much weaker and more internally sourced than the raw usage claims imply
FDA proposed against including VIP on the 503A bulks list in 2016 and again in 2019
but as of April 22, 2026, VIP still appears in 503A Category 1 under evaluation
and it is not on the currently published July 2026 or February 2027 PCAC peptide agendas

So VIP is not best understood as:

a mainstream approved peptide
or a typical gray-market peptide
or a peptide currently front-and-center in the 2026 FDA review cycle

It is a long-running clinical niche peptide with a real evidence base, a controversial practice community, and one of the strangest compounding histories in the space.