Peptide education
VIP
Vasoactive intestinal peptide
VIP is vasoactive intestinal peptide, a 28-amino-acid signaling molecule your own body makes, active in blood vessels, gut, immune cells, and lung. The synthetic version, aviptadil, has been tested in pulmonary hypertension, sarcoidosis, and COVID respiratory failure, and one UK product combines it with phentolamine for erectile dysfunction. None of that is what most buyers meet. The mass-market version is a compounded nasal spray sold into CIRS and mold-illness circles, a use resting on one small open-label paper and a great deal of clinic testimony.
VIP's lung and immune biology is real and small pulmonary studies back it, but the human evidence is narrow while the claims are not. The COVID program ended without a mortality benefit, the one authorized product is a UK erectile-dysfunction combination, and CIRS nasal-spray use still rests on an open-label paper plus anecdotes.
Overview
Quick answer
VIP, aviptadil, Invicorp, and compounded or gray-market VIP nasal spray refer to different settings. Native VIP is the body peptide. Aviptadil is the synthetic peptide used in studies. Invicorp combines aviptadil with phentolamine for erectile dysfunction in the UK. CIRS and mold-illness discussions usually involve compounded or clinic-supplied nasal spray, where the human evidence, product oversight, and quality controls are very different.
What is VIP?
An endogenous 28-amino-acid peptide that signals mainly through VPAC1 and VPAC2 receptors, raising cAMP in target cells. Aviptadil is the synthetic drug form used in studies and in one authorized combination product.
What do people use it for or talk about?
Researchers have tested it in pulmonary hypertension, pulmonary sarcoidosis, checkpoint-inhibitor pneumonitis, and severe COVID. Clinics and forums mostly talk about something else: intranasal VIP for CIRS, mold illness, neuroinflammation, and chronic inflammatory symptoms.
What route and dose patterns appear in published sources?
Published work spans three-day IV infusions in COVID protocols, a single 100-mcg inhaled dose during heart catheterization, four weeks of nebulized VIP in sarcoidosis, 67 mcg nebulized three times daily in one COVID registry, and Invicorp's 25 mcg aviptadil plus 2 mg phentolamine injection. CIRS nasal use has no comparable published standard.
How do route and claim affect the evidence?
They decide everything. VIP is vasoactive and unstable, so a hospital infusion, a nebulizer, an intracavernosal injection, and a compounded nasal spray behave like four different drugs, and evidence from one cannot be spent on another.
Reported practice
Commonly reported protocol
Clinic intranasal protocols. Community-reported patterns, not verified by controlled human trials and not a use recommendation. Full use-pattern detail
Evidence
Evidence snapshot
VIP has a credible receptor and cAMP signaling rationale, with lung-centered effects involving vascular tone, bronchial smooth muscle, alveolar type II cells, surfactant biology, and inflammatory cytokines.
Pulmonary sarcoidosis and checkpoint-pneumonitis studies create early human interest, but they are too small or case-level for broad immune or inflammation claims.
Pulmonary hypertension studies reported acute physiologic effects, such as pulmonary vasodilation and improved cardiac output measures, in small study settings.
Early COVID aviptadil work generated exploratory findings, but a later NIH platform trial did not show a mortality benefit.
CIRS and mold-illness discussion is visible in clinic and forum settings, but the evidence points mainly to one small open-label nasal-spray paper plus anecdotal reports rather than blinded confirmatory trials.
VIP can adsorb to surfaces and show stability problems. For nasal, inhaled, or injectable products, identity, concentration, sterility, endotoxin, handling, storage, and delivered dose all matter.
Claims
Common claims vs evidence
| Claim | Human evidence | Mechanistic evidence | Anecdotal evidence | Verdict |
|---|---|---|---|---|
| VIP is a real anti-inflammatory peptide. | The human evidence is small, condition-specific pulmonary work rather than a general anti-inflammatory treatment record. The sarcoidosis phase II study reported reduced TNF-alpha production in BAL cells after nebulized VIP, and a checkpoint-pneumonitis case report described local inhaled use. | The mechanism is credible. VIP signals through VPAC1 and VPAC2, raises cAMP in target cells, and is described in immune literature as affecting macrophages, dendritic cells, microglia, inflammatory cytokines, and tolerance-associated immune responses. | Clinic and online discussions often turn that biology into broad immune reset or inflammation claims, especially around nasal spray. Those reports show what people use VIP for, not whether the effect holds up in controlled care. | Fair as mechanism language. Too broad as a clinical efficacy claim unless the claim names the condition, route, dose, duration, and outcome. |
| VIP treats CIRS or mold illness. | CIRS and mold-illness use appears mostly in public clinic and forum discussion, with one open-label 20-patient nasal-spray paper often cited in that setting. A small open-label report cannot tell what would happen in a blinded, replicated trial. | VIP's immune and lung biology gives the claim a biological rationale, but evidence that this biology improves a broad, mixed symptom cluster in patients is lacking. | Clinic pages and Reddit-style discussions describe compounded VIP nasal spray for CIRS, mold illness, neuroinflammation, and related symptoms. The same online material includes mixed reports, side effects, no clear benefit for some users, and high out-of-pocket cost. | Clinics and forums discuss this use, but the public evidence is still mostly open-label, clinic, and anecdotal. |
| VIP helps pulmonary hypertension or pulmonary inflammation. | Small pulmonary hypertension studies reported acute hemodynamic effects with inhaled aviptadil, and the sarcoidosis phase II study reported biomarker changes after four weeks of nebulized VIP. The checkpoint pneumonitis case report is a single-patient observation. | The lung is a direct place to study VIP because available protocol materials describe VIP binding in pulmonary tissue, including alveolar type II cells, plus bronchodilation, vasodilation, surfactant-related biology, and immune modulation. | The respiratory trial literature is more directly relevant here than consumer anecdotes. Online use usually talks about immune symptoms and CIRS rather than measured pulmonary hemodynamics. | A legitimate research area with small human findings. It is not a settled respiratory treatment claim. |
| Aviptadil was a COVID rescue treatment. | Expanded-access and early COVID materials reported exploratory findings, but the later TESICO/NIH platform trial reported no day-90 mortality benefit. The later trial reported 38% mortality with aviptadil versus 36% with placebo. | The COVID rationale came from lung VIP biology, alveolar type II cell protection, surfactant effects, vasodilation, and proposed immune modulation. That rationale was reasonable to test, but it did not become a clear survival claim. | COVID-era sponsor and emergency-use interest amplified the narrative. The later negative platform-trial result now has to sit beside those early findings. | Later COVID trial results undercut the rescue-treatment story that grew out of early aviptadil interest. |
| VIP is already an approved medicine. | There is an approved-product example, but it is narrow and different from the immune discussion. UK materials describe Invicorp, a combination of aviptadil and phentolamine, for erectile dysfunction. FDA orphan designation for sarcoidosis is not FDA approval for that use. | Erectile dysfunction use depends on local vasoactive effects in a combination product. Those ED data do not settle whether VIP helps immune, lung, CIRS, or nasal spray uses. | Some marketing turns "VIP is approved somewhere" into broad legitimacy language. The product, jurisdiction, route, and indication still have to stay attached to the claim. | The product and use case matter. Invicorp is erectile-dysfunction context; it does not make VIP a broad immune, lung, CIRS, or nasal-spray therapy. |
| Compounded or gray-market VIP can be trusted if it has a COA. | This is a product-risk question, not an efficacy question. FDA says compounded drugs are not FDA-approved and are not pre-verified by FDA for safety, effectiveness, or quality before marketing. | VIP is especially quality-sensitive because analytical work reports adsorption to surfaces and stability problems. That can affect measured concentration and delivered dose before sterility or endotoxin questions are even considered. | Online products and clinic offerings may emphasize purity, vial identity, or nasal-spray access. A single HPLC purity number does not verify sterile quality, correct concentration, storage integrity, or appropriate route. | A COA can be one limited document. For nasal, inhaled, or injectable confidence, concentration, sterility, endotoxin, storage, and delivered-dose details still matter. |
Bottom line
Main takeaway
VIP is a real body peptide with genuine lung and immune pharmacology, but its most popular use, nasal spray for CIRS or mold illness, sits on the thinnest evidence on the page.
Do not average this record: a catheterization-lab hemodynamic study, a negative COVID mortality trial, a UK ED combination, and a clinic nasal spray are different products answering different questions.
Anchor on the TESICO protocol and mortality result, the pulmonary hypertension and sarcoidosis studies, the Invicorp product materials, and the LC-MS/MS characterization paper showing why VIP's adsorption and instability make product claims fragile.
Identity
What it is
VIP belongs to the glucagon-secretin peptide family and acts through VPAC1 and VPAC2 receptors. It raises cAMP, relaxes vascular and bronchial smooth muscle, and modulates immune cells. The lung holds all three targets in one organ, which is why serious VIP research is lung research.
The published human record is small but real: temporary selective pulmonary vasodilation after a single inhaled dose, reduced TNF-alpha output from lung immune cells after four nebulized weeks in sarcoidosis, one striking pneumonitis case report. Then COVID tested the idea at scale, and the TESICO platform trial found no day-90 mortality benefit, 38% on aviptadil versus 36% on placebo.
The consumer record is a different animal. CIRS and mold-illness clinics built intranasal VIP into multi-month protocols, citing one open-label study of 20 patients and years of accumulated testimony. That is a demand story with a plausible mechanism attached, not a controlled evidence base.
The molecule itself is uncooperative. VIP sticks to container surfaces, degrades readily, and clears from blood within minutes, so what a label says and what a spray delivers can part company quickly.
How people talk about it online
CIRS owns the VIP conversation online. Mold-illness clinics present intranasal VIP as a late step in long protocols, forums trade titration stories, and the one 20-patient open-label paper gets cited well past its weight.
The user reports are genuinely mixed, which is itself information: alongside people who credit the spray with turning a corner there are no-effect reports, side-effect complaints, and sticker shock. That spread is what an uncontrolled market looks like.
Product talk is the quiet hazard. The same three letters appear on compounded sprays, research vials, and clinic programs, for a molecule documented to adsorb to surfaces and degrade in storage. A purity number on a COA does not say how much VIP survives the bottle.
Use context
Routes, doses, and cycle patterns
VIP route and protocol details change sharply by setting. Published respiratory sources include IV infusion, inhaled or nebulized aviptadil, and short study durations. Invicorp uses intracavernosal injection in an erectile dysfunction combination product. CIRS and mold-illness sources mainly discuss compounded nasal spray, but public sources leave the dose, frequency, and cycle standard unresolved for that use.
Human studies and product labels
Invicorp authorized product
- Purpose
- Erectile dysfunction
- Context
- UK product-review and product-material context
- Route
- Intracavernosal injection
- Amount
- 25 micrograms aviptadil plus 2 mg phentolamine
- Frequency
- Product materials describe maximum limits, including not more than once daily or three times weekly
- Duration
- Used per episode in the product context, not a chronic immune protocol
Invicorp is an erectile-dysfunction combination product. It does not answer VIP nasal spray, CIRS, immune-modulation, or pulmonary-inflammation claims.
Expanded-access and TESICO IV aviptadil studies
- Purpose
- Critical COVID-19 respiratory failure or ARDS research
- Context
- Protocol-level COVID research materials
- Route
- Intravenous infusion
- Amount
- 50, 100, then 150 pmol/kg/hr
- Frequency
- Three 12-hour daily infusions
- Duration
- Days 1 to 3
These hospital protocols tested escalating IV exposure in severe respiratory illness. Later platform-trial mortality data did not turn this into a COVID survival treatment.
NCT04536350 inhaled COVID study
- Purpose
- COVID-19 respiratory research
- Context
- Trial registry and protocol-publication summary
- Route
- Nebulized or inhaled aviptadil
- Amount
- 67 mcg
- Frequency
- Three times daily
- Duration
- 10 days
This inhaled schedule comes from a COVID trial design. It does not describe consumer inhalation products or chronic outpatient immune use.
NCT04844580 inhaled aviptadil study
- Purpose
- COVID-19 respiratory research
- Context
- Trial registry summary
- Route
- Inhaled aviptadil
- Amount
- Not reported publicly in the registry summary
- Frequency
- Twice daily, with doses 30 minutes apart
- Duration
- Minimum 7 days and maximum 14 days in the registry summary
Another inhaled-regimen example exists, but public details are too limited to compare dose exposure with other inhaled or nebulized sources.
Acute pulmonary hypertension study
- Purpose
- Pulmonary hemodynamic testing
- Context
- Primary abstract and citation-database listing
- Route
- Inhaled aviptadil during right-heart catheterization
- Amount
- Single 100-mcg dose
- Frequency
- Single acute exposure
- Duration
- Acute physiology study
The study reported temporary, selective pulmonary vasodilation and improved stroke volume and mixed venous oxygen saturation. It was not a long-term pulmonary hypertension outcome trial.
Pulmonary sarcoidosis phase II study
- Purpose
- Pulmonary inflammatory disease signal
- Context
- Open phase II study
- Route
- Nebulized VIP
- Amount
- Exact dose not publicly reported
- Frequency
- Not publicly reported
- Duration
- 4 weeks
The study was described as safe and well tolerated and reported reduced TNF-alpha production in BAL cells. Exact dose and device details remain public gaps.
Real-world discussion
Clinic intranasal protocols
- Purpose
- Mold-illness and inflammatory discussion
- Context
- CIRS-style clinics and community reports
- Route
- Intranasal spray, usually pharmacy-compounded
- Amount
- Clinic protocols in the Shoemaker lineage commonly describe around 50 mcg per spray, one to four sprays daily, titrated upward under monitoring.
- Frequency
- One to four times daily in clinic descriptions
- Duration
- Multi-week to multi-month in clinic programs
VIP is a vasoactive peptide with real hypotension risk, which is why the clinic lineage that uses it pairs it with blood-pressure and lipase monitoring. Community use without that monitoring inherits the risk without the guardrails. Reported as context, not a recommendation.
What varies
- Goal: pulmonary hemodynamics, sarcoidosis biomarkers, COVID respiratory failure, ED, CIRS, and wellness use are different claims.
- Route: IV, inhaled, nebulized, intranasal, and intracavernosal routes do not imply the same exposure or risk.
- Amount: published materials provide concrete amounts for several study and product contexts, but not a reliable CIRS nasal-spray standard.
- Duration: study durations range from acute single exposure to 3 hospital infusion days, 10 to 14 inhaled-study days, and 4 weeks in sarcoidosis.
- Product quality: VIP adsorption and instability make identity, concentration, container contact, storage, sterility, and endotoxin harder to ignore.
Human data
Human evidence
VIP has genuine human pharmacology: receptor-level plausibility plus small studies in pulmonary hypertension and sarcoidosis with measurable acute effects. What it lacks is a controlled treatment win in the settings people actually buy it for. The largest controlled test, the NIH TESICO platform trial in COVID ARDS, found no day-90 mortality benefit. The only authorized product in the cited record is Invicorp, an aviptadil-phentolamine erectile-dysfunction combination with no bearing on immune or nasal use. CIRS and mold-illness nasal spray, the most visible consumer use, rests on one small open-label study and accumulated clinic and forum reports.
Evidence maturity
VIP has real human pharmacology and one narrow approved combination product, but the loudest consumer claims sit on the thinnest evidence.
VIP signals through VPAC1 and VPAC2 receptors with credible lung, vascular, and immune pharmacology.
Acute pulmonary-hypertension hemodynamic studies, a sarcoidosis phase II biomarker study, and a single-patient pneumonitis case provide early signals.
Early exploratory findings gave way to the NIH TESICO platform trial, which found no day-90 mortality benefit.
Invicorp, an aviptadil-plus-phentolamine combination, is authorized in the UK for erectile dysfunction only; there is no U.S. approval.
Compounded CIRS and mold-illness nasal spray rests mainly on one small open-label paper plus clinic and forum reports.
| Study / evidence area | Population | Design | Product context | Main outcome | Limitations | Weight |
|---|---|---|---|---|---|---|
| Pulmonary sarcoidosis phase II study | 20 people with pulmonary sarcoidosis | Open phase II study | Nebulized VIP in a research context | The study was described as safe and well tolerated and reported reduced TNF-alpha production in BAL cells after four weeks. | Small, open-label, biomarker-heavy, and exact nebulized dose or device details were not verified. | Weak to moderate |
| Pulmonary hypertension acute inhalation study | 20 patients in an acute pulmonary hemodynamic study | Acute physiology study | Inhaled aviptadil during right-heart catheterization | A single 100-mcg inhaled dose caused small, temporary, selective pulmonary vasodilation and improved stroke volume and mixed venous oxygen saturation. | Acute physiology does not settle long-term clinical outcomes or routine pulmonary hypertension treatment benefit. | Weak to moderate |
| Earlier primary pulmonary hypertension study | 8 patients with primary pulmonary hypertension | Small early clinical study | VIP or aviptadil pulmonary research context | VIP decreased mean pulmonary artery pressure and increased cardiac output and mixed venous oxygen saturation in the published report. | Very small and older; the published report did not include enough regimen detail for dose comparisons. | Weak |
| Checkpoint-inhibitor pneumonitis case report | 1 patient | Case report | Inhaled VIP or aviptadil for local pulmonary inflammation | Authors supported inhaled VIP as local anti-alveolar-inflammatory therapy in this case. | One case is a weak basis for efficacy, safety, dose selection, or broad use. | Anecdotal |
| Critical COVID-19 expanded-access experience | 21 aviptadil patients in an open expanded-access program with concurrent controls | Open-label expanded access | Hospital IV aviptadil during critical COVID-19 respiratory illness | Expanded-access reporting described four-week survival of 90% in the aviptadil cohort, with hypotension in 5 of 21 and diarrhea in 4 of 21. | Non-randomized, confounded by co-treatments, and later controlled evidence was less favorable. | Weak |
| NCT04311697 randomized COVID study | 196 patients reported in the published summary | Randomized COVID study | IV aviptadil | Preliminary summary reported about 71 to 72% survival at 28 days in both groups, with exploratory time-to-recovery finding in a subgroup. | Exploratory and not a decisive survival result. | Weak to moderate |
| TESICO hospitalized COVID-19 ARDS platform trial | Hospitalized COVID-19 ARDS patients | NIH platform trial | Aviptadil versus placebo | TESICO reported day-90 mortality of 38% with aviptadil versus 36% with placebo, with a hazard ratio of 1.04. | This later negative result weighs against broad COVID efficacy claims. | Moderate |
| Invicorp erectile dysfunction product materials | Men with erectile dysfunction in product-review materials | Product-review and randomized-study context | Aviptadil plus phentolamine combination product | The product materials support clinical activity for the combination product and describe a UK authorization context. | ED combination-product evidence describes local erectile-dysfunction use, not immune, pulmonary, CIRS, nasal-spray, or gray-market VIP claims. | Moderate |
Cautions
Safety and unknowns
- Hypotension is a central safety issue because VIP is vasoactive. COVID protocol materials, older physiology studies, and product reviews repeatedly point to blood-pressure and vascular effects.
- Diarrhea, flushing, tachycardia, bradycardia, and injection-site bruising appear in reported safety materials, depending on route and product.
- VIP has a very short circulating half-life in older human PK sources, which makes delivery route, formulation, and exposure assumptions especially important.
- Chronic outpatient use of compounded nasal or inhaled VIP is not characterized like a published product program.
- FDA compounding materials state that compounded drugs are not FDA-approved and are not pre-verified by FDA for safety, effectiveness, or quality before marketing.
- CIRS and mold-illness use has large public interest but weak confirmatory evidence. It requires more convincing blinded human trials before treatment claims are credible.
Product quality
A vial label is only a starting point
VIP is quality-sensitive. A 2025 LC-MS/MS characterization paper described adsorption to surfaces, instability, and the importance of mass spectrometry for peptide identification. For nasal, inhaled, or injectable use, a purity percentage alone leaves too many questions open.
FDA sterility and endotoxin guidance matters here because VIP discussion often involves nasal, inhaled, or injectable products outside an approved immune or pulmonary drug label.
Identity
A label saying VIP does not verify the peptide identity, salt form, degradation profile, or that aviptadil and native VIP are being handled consistently.
Concentration and adsorption
VIP can stick to surfaces and show stability problems, so the delivered amount may not match the vial, spray, or COA number unless the method is shown for that product.
Sterility and endotoxin
Nasal, inhaled, and injectable routes raise microbial and endotoxin questions that are not answered by a simple HPLC purity result.
Storage and handling
Temperature, container contact, reconstitution, shipping, and time after preparation can matter for a short-lived peptide with stability concerns.
Mechanism
How it is proposed to work
VIP acts like a signaling messenger. By binding VPAC1 and VPAC2 receptors, it tends to raise cAMP inside target cells, which can change vascular tone, bronchial smooth muscle behavior, epithelial function, immune-cell activity, and cytokine release.
Lung biology is central because protocol sources describe VIP binding in pulmonary tissue, including alveolar type II cells, with proposed effects on surfactant production, bronchodilation, vasodilation, platelet activation, and inflammatory injury.
Immune sources describe VIP effects on macrophages, dendritic cells, microglia, inflammatory cytokines, chemokines, and tolerance-associated phenotypes. That explains the interest in sarcoidosis, pneumonitis, and CIRS-like claims.
Translation is difficult here: a short half-life, route-dependent exposure, adsorption, and stability problems can keep a mechanistically relevant peptide from producing consistent outpatient clinical effects.
The same vasodilatory pharmacology that makes VIP interesting in inflammatory models is what makes unmonitored use a blood-pressure risk.
FAQ
Common questions
What is VIP used for in clinics?
VIP appears mainly in CIRS-style (mold-illness) clinic protocols, usually as compounded intranasal sprays around 50 mcg per spray, one to four times daily, titrated under monitoring.
Is VIP safe to self-administer?
VIP is vasoactive — it can drop blood pressure, which is exactly why the clinic lineage that uses it pairs it with blood-pressure and lipase monitoring. Unmonitored use inherits the risk without the guardrails.
Does VIP have real drug research behind it?
Yes, as aviptadil it reached human trials for lung and inflammatory indications, though none matured into an approved product for those uses. That history is separate from the mold-illness protocol rationale.
Details
Technical details
Sources
References
- 1.
TESICO protocol appendix. TESICO/ACTIV-3b aviptadil protocol appendix
- 2.
FDA orphan designation. FDA orphan-drug designation page for aviptadil in sarcoidosis
- 3.
FDA compounding Q&A. FDA compounding Q&A
- 4.
FDA 503A bulks document. FDA 503A bulk substances document
- 5.
FDA USApeptide warning letter. FDA warning letter to USApeptide.com
- 6.
FDA peptide-seller warning letters. FDA warning letters to peptide sellers including Summit Research Peptides and Gram Peptides
- 7.
FTC COVID-claim warnings. FTC COVID-claim warning materials
- 8.
Invicorp product materials. AWTTC / NHS Wales / SMC Invicorp materials
- 9.
Dinsmore 1999 study. Dinsmore 1999 PubMed abstract
- 10.
Sandhu 1999 study. Sandhu 1999 PubMed abstract
- 11.
Prasse 2010 sarcoidosis study. Prasse 2010 sarcoidosis abstract
- 12.
Leuchte 2008 pulmonary study. Leuchte 2008 pulmonary-hypertension abstract and ERJ citation page
- 13.
Petkov 2003 JCI/PMC article. Petkov 2003 JCI/PMC article and later VIP review citation
- 14.
Frye 2020 case report. Frye 2020 NEJM case report
- 15.
NCT04311697 registry and publication. NCT04311697 registry record and sponsor-era publication
- 16.
Brown 2023 TESICO result. Brown 2023 TESICO PubMed abstract
- 17.
NCT04536350 inhaled study. NCT04536350 and protocol-publication abstract
- 18.
NCT04844580 registry record. NCT04844580 trial registry record
- 19.
Domschke 1978 PK source. Domschke 1978 PK and related references
- 20.
Frase 1987 human study. Frase 1987 healthy-human cardiovascular study
- 21.
VIP LC-MS/MS characterization. Koyuturk and Sener 2025 LC-MS/MS VIP characterization
- 22.
VIP immunology reviews. VIP immunology reviews and summaries
- 23.
CIRS nasal-spray discourse. Clinic, Reddit, and gray-market discourse around VIP nasal spray and CIRS
- 24.
FDA endotoxin and aseptic guidance. FDA endotoxin and aseptic-processing guidance