Evidence review
VIP (Vasoactive Intestinal Peptide): What the Evidence Actually Shows
VIP is a real human neuropeptide under active FDA review — but its best-known use, the Shoemaker CIRS protocol, has no independent efficacy trial behind it.
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VIP — vasoactive intestinal peptide — is a naturally occurring human neuropeptide with genuine, decades-old physiological research behind it, best known in the compounding-pharmacy market today as the final step of the "Shoemaker protocol" for chronic inflammatory response syndrome (CIRS), a mold-illness framework. Those two facts sit in real tension: VIP itself is a legitimate research molecule, but its most commercially visible current use has a much thinner evidence base than its broader physiology literature might suggest.
What it actually is
VIP is a naturally occurring 28-amino-acid neuropeptide, part of the glucagon/secretin peptide family, with broad, well-established physiological roles: vasodilation, gut motility and secretion regulation, and immunomodulation. It is not a research-chemical-market invention — it is an endogenous human signaling molecule that has been studied since the 1970s. That basic-science legitimacy is real, and it is also separate from the question of whether any specific product sold as "VIP" today is backed by a clinical trial for the use it's marketed for.
What VIP actually is
VIP: a 28-amino-acid human neuropeptide
Glucagon/secretin peptide family — naturally occurring, not a lab invention
Physiological roles: vasodilation, gut motility, immunomodulation
Well-established basic-science research base
Marketed today as: Shoemaker CIRS protocol nasal spray
A specific, non-consensus clinical application — distinct from the broader physiology literature
Three real, distinct research and clinical threads
VIP's actual research and clinical-use history splits into three genuinely different applications, each with its own evidence base. Pulmonary hypertension: a 2008 study administered a single 100-microgram inhaled dose of aviptadil (synthetic VIP) to 20 patients with pulmonary hypertension during right-heart catheterization, reporting a "small and temporary but significant selective pulmonary vasodilation" — the study's own authors describe the effect as "modest and short-lived," calling for further research at higher doses1. Erectile dysfunction: a 2024 comprehensive history of ED injection therapy confirms a real, still-referenced combination product — "a mixture of a vasoactive intestinal polypeptide (aviptadil) and phentolamine" — among the agents used in self-injection ED therapy since the 1980s2, a genuinely more established clinical application than either of the other two. COVID-19: aviptadil was tested in ARDS trials during the pandemic with results contested enough that a 2022 published commentary is titled "Aviptadil for COVID-19: A Case Study and Call to Action About the Challenges of Research During a Global Pandemic3" — this article reports that controversy as unresolved rather than picking a side.
Three distinct research threads, not one
| Application | Evidence |
|---|---|
| Pulmonary hypertension (inhaled aviptadil) | One 20-patient dose-finding study — "modest and short-lived" vasodilation, per its own authors |
| Erectile dysfunction (aviptadil + phentolamine injection) | A real, still-referenced combination product in ED self-injection therapy since the 1980s |
| COVID-19 ARDS (aviptadil) | Tested, results contested — described in a 2022 published commentary as facing "challenges of research during a global pandemic" |
| Shoemaker CIRS protocol (intranasal VIP) | A named, specific clinical use with no independent peer-reviewed efficacy trial located |
The Shoemaker CIRS protocol: a real, named, but non-consensus use
VIP's best-known current market use — the final step of Dr. Ritchie Shoemaker's CIRS ("chronic inflammatory response syndrome") mold-illness protocol, dosed intranasally — is worth separating clearly from VIP's broader research base. A direct PubMed author search for Shoemaker's own published work combined with VIP returns exactly one paper: a 2010 case/control study of chronic ciguatera poisoning (a different biotoxin illness, not mold specifically) that uses REDUCED VIP levels as a diagnostic biomarker distinguishing cases from controls — not a trial of VIP nasal spray as a treatment4. A broader search for peer-reviewed evidence of VIP nasal spray specifically treating CIRS or mold-related illness, checked paper-by-paper for this article, did not locate an independent, peer-reviewed treatment-efficacy trial. Read this plainly: Shoemaker's framework does have a peer-reviewed publication measuring VIP as a marker of illness in a related biotoxin condition — that much is real — but the specific "VIP replacement/nasal spray" treatment step popularized in the CIRS/mold-illness community does not have independent randomized-trial support behind it, distinct from the physiological legitimacy of VIP itself.
A real naming trap: DailyMed's only listing is for cattle, not people
DailyMed's structured-product-label search for "vasoactive intestinal peptide" returns exactly one result. Fetching that label's own structured data directly — not just its search-result title — shows its FDA approval code is literally "bulk ingredient for animal drug compounding5." This is a veterinary bulk-chemical filing, unrelated to any human product — the same shape of naming trap this site's Gonadorelin calculator page already documented for "Factrel" (a discontinued human drug name later reused for an unrelated cattle product). There is no human-labeled VIP product on DailyMed of any kind.
What's actually been tested, by specific application
- Basic physiology (vasodilation, gut motility, immunomodulation)STRONG evidence
Decades of established research — VIP is a naturally occurring, well-characterized human neuropeptide.
- Pulmonary hypertension (inhaled)WEAK evidence
One real dose-finding study, 20 patients, effect described by its own authors as modest and short-lived.
- Erectile dysfunction (injection, with phentolamine)MODERATE evidence
A real, established combination therapy referenced in a 2024 comprehensive clinical history.
- Shoemaker CIRS protocol (intranasal, as a treatment)NONE evidence
No independent peer-reviewed efficacy trial located — Shoemaker's own published VIP work measures it as a biomarker, not as a tested treatment.
The regulatory picture: genuinely different from the rest of this batch
VIP's U.S. regulatory status is meaningfully different from every other compound in this five-article batch. Checked live for this article, VIP appears on FDA's CURRENT 503A Bulks List (updated May 14, 2026) under Category 1 — "Bulk Drug Substances Under Evaluation6" — meaning it is under active, ongoing FDA compounding review right now, not absent from consideration (like Cerebrolysin and Noopept) and not stuck in the safety-page-only limbo Selank and Thymosin Alpha-1 occupy elsewhere in this batch. openFDA's FAERS database returns 6 total reports for "VASOACTIVE INTESTINAL PEPTIDE" and 20 for "AVIPTADIL," the synthetic drug-candidate name used in its clinical trials7 — small numbers, but non-zero, consistent with genuine if limited clinical use.
What this means if you're considering it
None of the 31 providers this site's own reviews cover sell VIP — this site's own identity-layer research confirms it is not tagged to any reviewed seller. The real-world market and research form for VIP is nasal spray or inhalation, not an injectable vial, which is why this site does not carry a VIP reconstitution calculator. VIP itself is a legitimate, decades-studied human neuropeptide, actively under FDA compounding review — a genuinely different regulatory posture than most of this corpus. Its use in erectile-dysfunction injection therapy and its modest inhaled pulmonary-hypertension signal are both real, if limited. Its best-known current market application, the Shoemaker CIRS protocol, is a specific, named clinical framework without an independent peer-reviewed efficacy trial behind the nasal-spray step specifically — a distinction worth holding onto rather than treating VIP's broader physiological legitimacy as evidence for that particular use. If you're researching other immune-modulatory peptides this site covers, our Thymosin Alpha-1 evidence review covers a different immunomodulatory peptide with a much longer international approval history and a genuinely larger human trial base.
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Frequently asked questions
Is VIP a real, studied compound?
Yes — VIP (vasoactive intestinal peptide) is a naturally occurring 28-amino-acid human neuropeptide with decades of established physiological research (vasodilation, gut motility, immunomodulation). It is also currently under active FDA compounding review, listed in Category 1 ("Bulk Drug Substances Under Evaluation") on FDA's current 503A Bulks List.
Does the Shoemaker CIRS protocol's use of VIP have clinical trial support?
Not independently, as far as this article could locate. A direct search of Dr. Ritchie Shoemaker's own published work combined with VIP found one paper — a biomarker study in chronic ciguatera poisoning, not a treatment trial. A broader search for peer-reviewed evidence of VIP nasal spray treating CIRS or mold-related illness specifically did not locate an independent efficacy trial. This is a real, named clinical protocol without independent randomized-trial support behind that specific step.
Is VIP sold as an injectable?
Its real-world market and research forms are nasal spray (the Shoemaker CIRS protocol, intranasally at 200-400 mcg/day per multiple independent sources) and inhalation (the pulmonary-hypertension research, and one erectile-dysfunction combination product that IS injected). No standalone injectable VIP vial product for general reconstitution was found, which is why this site does not carry a VIP reconstitution calculator.
Is VIP FDA-approved?
No FDA-approved human drug product exists — DailyMed's only listing for "vasoactive intestinal peptide" is coded as a bulk ingredient for animal (cattle) drug compounding, not a human product. VIP is, however, genuinely under active FDA review as a compounding bulk substance, listed in Category 1 of FDA's current 503A Bulks List.
References
- Leuchte HH, Baezner C, Baumgartner RA, Bevec D, Bacher G, Neurohr C, Behr J (2008). Inhalation of vasoactive intestinal peptide in pulmonary hypertension. European Respiratory Journal. https://pubmed.ncbi.nlm.nih.gov/18978135/
- Porst H, Lewis R, Virag R, Goldstein I (2024). A comprehensive history of injection therapy for erectile dysfunction, 1982-2023. Sexual Medicine Reviews. https://pubmed.ncbi.nlm.nih.gov/38644056/
- Auld SC (2022). Aviptadil for COVID-19: A Case Study and Call to Action About the Challenges of Research During a Global Pandemic. Critical Care Medicine. https://pubmed.ncbi.nlm.nih.gov/36227034/
- Shoemaker RC, House D, Ryan JC (2010). Defining the neurotoxin derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: a case/control study. Neurotoxicology and Teratology. https://pubmed.ncbi.nlm.nih.gov/20685390/
- National Library of Medicine (2026). DailyMed structured-product-label search for "vasoactive intestinal peptide" — one result, coded "bulk ingredient for animal drug compounding" (a veterinary filing, not a human product). DailyMed — U.S. National Library of Medicine (official archive of FDA-approved drug labeling). https://dailymed.nlm.nih.gov/dailymed/services/v2/spls.json?drug_name=vasoactive%20intestinal%20peptide
- U.S. Food and Drug Administration (2026). Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act — "Vasoactive Intestinal Peptide" listed in Category 1 (Bulk Drug Substances Under Evaluation). FDA.gov — Human Drug Compounding, updated May 14, 2026. https://www.fda.gov/media/94155/download?attachment
- U.S. Food and Drug Administration (2026). FDA Adverse Event Reporting System (FAERS) — 6 total reports for "VASOACTIVE INTESTINAL PEPTIDE" and 20 for "AVIPTADIL", data last updated July 30, 2026. openFDA — drug/event public API. https://api.fda.gov/drug/event.json?search=patient.drug.medicinalproduct:%22VASOACTIVE+INTESTINAL+PEPTIDE%22
Medical disclaimer: This content is for general educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a licensed healthcare professional before starting, stopping, or changing any treatment.
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