Ground Truth Peptides
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VIP (Vasoactive Intestinal Peptide)

Aviptadil, RLF-100, ZYESAMI, vasoactive intestinal polypeptide, VIP 28

The Ground Truth Score

four plain questions, never one number

Real human RCTs exist, but they're negative, and the popular nasal-spray use is a different, near-unproven story

Bottom line

VIP is an endogenous peptide with a genuine drug-development history (the IV form, aviptadil, ran through Phase 3 RCTs that mostly failed), but the intranasal/subcutaneous "CIRS / mold-recovery" use that drives consumer interest rests almost entirely on one clinic's small, uncontrolled studies and should be treated as unproven.

Does the science back it?

BHuman-trial signal

Do real people feel it?

Mixed

Is it safe?

CThinly characterized

Could it be placebo?

Likely placebo

"Do real people feel it?" is anecdote, not proof, weighted up because the science is thin, never because it beats a trial. And "could it be placebo?" is not an insult: if you feel better, that's real to you. The point is only to know whether you're paying peptide prices for an expectation.

Why is the evidence this thin? It's mostly economics →

Dose at a glance

full dosing ↓

REPORTED, not prescribed.

Reported, not prescribed. Verify your vial and your math.

First documented human use

Human pharmacokinetic and physiologic studies of infused VIP date to the late 1970s (e.g., a 1978 study of VIP in man characterizing its metabolic and circulatory effects). The synthetic form aviptadil entered formal FDA-authorized human trials beginning ~2001. So unlike most gray-market peptides, controlled human trials HAVE been completed, but the largest and most rigorous ones (COVID-19 respiratory failure) were negative on their primary endpoints. No controlled human trial supports the popular intranasal CIRS/anti-aging use specifically beyond small open-label cohorts.

Immune / anti-inflammatoryCIRS / mold recoveryLung & respiratory
The deep dive

The pitch

What people claim it does

Stated plainly and neutrally, exactly as you'll hear it. I grade each one below.

  • A 28-amino-acid peptide naturally produced in the human body (gut, nerves, immune cells) that signals through VPAC1/VPAC2 receptors to raise cAMP, broadly producing vasodilation and anti-inflammatory effects.
  • Marketed in compounding/wellness circles mainly as an intranasal spray to 'reset' chronic inflammation in mold-illness / CIRS, and to normalize biomarkers like TGF-beta1, MMP-9, C4a and VEGF.
  • The intravenous form, aviptadil (RLF-100/ZYESAMI), was developed as a pharmaceutical and tested in large COVID-19 respiratory-failure trials and earlier in pulmonary hypertension and sarcoidosis.
  • Investigated for its immunoregulatory effect on cytokines such as TNF-alpha and IL-6 in inflammatory lung disease.

The data behind each bullet

What actually backs it

B

The largest, most rigorous human trial, the NIH-run TESICO/ACTIV-3b RCT (28 US sites), found NO benefit of IV aviptadil for COVID-19 hypoxaemic respiratory failure versus placebo. This is the single most important data point and it is negative.

Randomized, placebo-controlled multicenter RCT published in The Lancet Respiratory Medicine (Sept 2023); explicitly concluded no evidence aviptadil improved clinical outcomes.

PubMed: TESICO aviptadil remdesivir COVID-19 RCT ↗
B

An earlier sponsor-affiliated Phase 2b/3 RCT (196 patients, 2:1 IV aviptadil vs placebo) MISSED its primary endpoint (alive and free from respiratory failure at day 60; OR 1.6, 95% CI 0.86-3.11). It reported a secondary survival signal (OR ~2.0) and reduced IL-6, but a missed primary endpoint plus sponsor involvement makes this hypothesis-generating, not confirmatory.

Randomized, double-blind, placebo-controlled trial published in Critical Care Medicine (2022); primary endpoint not statistically significant by the authors' own report.

PubMed: IV aviptadil critical COVID-19 60-day RCT (PMID 36044317) ↗
B

The FDA twice DECLINED Emergency Use Authorization for aviptadil (ZYESAMI) in critical COVID-19 (Nov 2021 and again mid-2022), citing insufficient benefit/risk data; aviptadil has never been FDA-approved for any indication.

FDA EUA decisions; company press releases and trade coverage. Confirms regulators did not find the human efficacy data adequate.

DailyMed / FDA search: aviptadil ↗
B

For pulmonary arterial hypertension, a Phase II RCT of inhaled VIP was NEGATIVE on both acute hemodynamics and after 3 months, and development was abandoned.

Phase II randomized controlled trial; reported negative and not advanced. Demonstrates failed efficacy in a second indication.

PubMed: inhaled vasoactive intestinal peptide pulmonary hypertension trial ↗
C

In sarcoidosis, a small open-label Phase II study (20 patients, 4 weeks nebulized VIP) was safe and reduced TNF-alpha in bronchoalveolar lavage, a real but early immunoregulatory signal, not an efficacy outcome.

Open-label human pilot study; biomarker change only, no controlled clinical-outcome endpoint.

PubMed: inhaled VIP immunoregulatory sarcoidosis ↗
C

The popular intranasal CIRS / 'gray-matter restoration' use rests on small (~20-patient), open-label, UNCONTROLLED studies from a single clinical network (Shoemaker), reporting biomarker normalization and MRI changes. No independent replication or controlled trial exists for this indication.

Open-label case series without control groups, largely from one research ecosystem; flagged as a key limitation. This is the weakest evidence in the profile and underlies the most common consumer use.

PubMed: vasoactive intestinal polypeptide chronic inflammatory response syndrome ↗

Mechanism

How it's assumed to work

Assumed mechanism (well-characterized for the endogenous peptide, but efficacy for the marketed uses is not established): VIP binds the G-protein-coupled receptors VPAC1 and VPAC2, raising intracellular cAMP. This drives smooth-muscle relaxation and vasodilation (including pulmonary and systemic vessels) and shifts immune cells toward an anti-inflammatory profile, lowering pro-inflammatory cytokines (TNF-alpha, IL-6) and modulating regulatory T cells. In CIRS theory it is claimed to re-regulate a dysfunctional innate-immune/neuroendocrine axis (TGF-beta1, MMP-9, C4a, VEGF, MSH), but that downstream clinical claim is theoretical, not proven.

Dosing & handling

What users and clinicians report

Reported, not prescribed

REPORTED, not prescribed. The most common consumer protocol is intranasal compounded spray, 50 mcg per metered spray, often up to ~4 sprays/day, run for an initial ~30 days and sometimes extended 12+ weeks. Some practitioners report subcutaneous protocols (e.g., ~50 mcg AM/PM). The pharmaceutical IV form (aviptadil) used very different, weight-based infused dosing in a monitored hospital setting, those numbers do not translate to at-home use.

Do not equate the supervised IV aviptadil doses from trials with at-home intranasal/subQ microdosing, they are different routes, formulations, and risk settings. Because VIP drops blood pressure, dose escalation should be conservative and any lightheadedness, flushing, or palpitations is a signal to stop. Intranasal CIRS dosing in the literature is prescriber-directed and sequenced after other treatments; using it first, or sourcing it gray-market, departs from even the limited evidence that exists.

Timing & food

Reported intranasal CIRS dosing is typically split through the day (e.g., morning and later doses, up to ~4x/day) rather than a single bolus, because the peptide's half-life is minutes. It is generally used independent of food. In the CIRS protocol the more important "timing" is sequence, not time-of-day: it is intended only after binders, MARCoNS eradication and environmental remediation, on the theory that giving it before the inflammatory drivers are removed wastes it. A first-dose blood-pressure check is prudent given the vasodilatory effect.

Half-life

Very short, roughly 1 to 2 minutes in plasma, cleared by rapid enzymatic degradation (and shortened further in inflammatory states by complement and protease activity) plus renal clearance. This extremely brief half-life is why the IV drug required continuous/repeated infusion and why intranasal or sustained-release approaches are pursued; it also undercuts simple assumptions about how long any systemic effect lasts.

Reconstitution sensitivity

As a peptide, VIP is heat- and protease-sensitive and prone to degradation. Lyophilized product should be stored cold; reconstituted with bacteriostatic or sterile water, kept refrigerated, protected from light, freeze-thaw cycles and agitation avoided. Compounded nasal sprays are similarly perishable and short-dated. Gray-market lyophilized vials carry real risk of degraded or mis-identified peptide, since the molecule does not tolerate poor handling.

Real-world signal

What people actually report

Anecdote, not proof, weighted because the science is thin. Here's the record, graded on volume, consistency, and how credible the sources are.

Mixed signal· Reports exist but contradict each other.

Volume

Moderate but niche and concentrated. Online discussion clusters heavily in the mold-illness/CIRS community (where it is the protocol's capstone) and in longevity/peptide forums; it is far less broadly discussed than BPC-157 or GLP-1 peptides. Much of the visible "information" is vendor and clinic marketing rather than independent user reports.

Consistency

Mixed and polarized. Within the CIRS community some users report meaningful gains in energy, cognition and inflammation; others report little change, intolerance (headache, BP drops, nasal irritation), high cost, or symptom return after stopping. Because it is always given last in a long protocol, even enthusiastic reports rarely isolate VIP itself.

Source credibility

Low to moderate. The most favorable claims trace back to a single clinical ecosystem (Shoemaker/SurvivingMold) and to vendors selling the product, both of which have incentives. Independent, skeptical, hard-outcome reports are sparse. The credible human evidence that does exist (the IV RCTs) is largely negative and is about a different route and indication than what consumers buy.

  • Anecdote, not proof: within the mold-illness/CIRS community, a subset describe a noticeable lift in energy, mental clarity and reduced 'inflamed' feeling once VIP nasal spray is added as the final protocol step, but typically after months of binders and remediation, so attribution is muddy.
  • Anecdote: many users report the vasodilatory effects directly, flushing, warmth, lightheadedness or a blood-pressure dip, headache, and nasal irritation/runny nose, especially on early doses; some find this limits how much they can use.
  • Anecdote: a recurring theme is cost and access frustration (prescription compounding, short shelf life) and reports that benefits fade after stopping, fueling debate over whether it is 'replacement' or just transient.
  • Anecdote: outside CIRS, longevity/peptide users tend to report it as subtle or unremarkable compared with the hype, and more skeptical voices note the failed COVID and pulmonary-hypertension trials when pushing back on marketing claims.

Placebo risk, High

Rated High for the popular intranasal/wellness use because the headline benefits people chase, more energy, clearer thinking, "less inflamed," better mood, are subjective and expectancy-prone, the product is expensive and effortful (raising commitment/justification bias), and it is administered at the emotional finish line of a long, hard recovery protocol when people most expect to feel better. The objective biomarker and MRI claims come from uncontrolled studies, so they cannot offset the placebo concern. (Placebo risk is lower in the supervised IV trial setting, where outcomes were hard and measured, and there the drug largely failed.)

Risk panel

What could go wrong

Adverse events

VIP is a potent vasodilator, so the consistent acute adverse effects are dose-dependent hypotension (sometimes with compensatory tachycardia), facial flushing/warmth, headache, dizziness, and GI effects (nausea, cramping, diarrhea). Intranasal use commonly causes nasal irritation and rhinorrhea. In the IV COVID and sarcoidosis trials these were generally mild and transient, and no drug-related SERIOUS adverse events were reported, a genuinely reassuring signal for short-course supervised IV use.

Theoretical concerns

Mechanistically, broad VPAC-receptor agonism affects vasculature, immune signaling, secretion and smooth muscle well beyond any single target tissue. The blood-pressure-lowering effect is the main acute hazard (caution with hypotension, hypovolemia, or concurrent vasodilators/antihypertensives). VIP also has growth/proliferative and pro-secretory signaling roles, so chronic unsupervised dosing in people with hormone-sensitive or proliferative conditions is a theoretical concern. Because the gut-hormone VIPoma tumor causes severe secretory diarrhea via VIP excess, very high or sustained exogenous exposure is biologically non-trivial.

Contraindications

Avoid or use only under close supervision in anyone with low baseline blood pressure, hemodynamic instability, hypovolemia, or significant cardiovascular disease, and be cautious with antihypertensives, nitrates, PDE5 inhibitors, or other vasodilators (additive hypotension). The IV form is an ICU/monitored drug for a reason. Pregnancy, breastfeeding, active malignancy, and pediatric use are uncharacterized for the wellness/intranasal context and should be treated as contraindications absent a prescriber's judgment.

Honest unknowns

The single biggest unknown is long-term safety of repeated intranasal/subcutaneous self-dosing over months, there is no controlled dataset for the CIRS/anti-aging pattern of use, only one clinic's open-label follow-up claiming durability. Product identity and purity from gray-market sources is unverified (real content, endotoxin, correct sequence). Whether nasal-delivered VIP reaches the brain or systemic targets at claimed doses, and whether the reported MRI/biomarker changes replicate independently, are open. Drug-interaction and chronic-use data outside short supervised IV courses are essentially absent.

Confound watch

In CIRS/mold protocols VIP is deliberately the LAST step, taken only after binders (cholestyramine/welchol), MARCoNS nasal antibiotic eradication, antifungals, correction of MSH/ADH and removal from the moldy environment. That means almost everything a user attributes to VIP is layered on top of months of other interventions plus environmental remediation, making clean attribution nearly impossible. Wellness users also frequently stack VIP with BPC-157, thymosin/TA1, NAD+, methylation support, and lifestyle changes. The strong subjective, energy/cognition-based nature of the reported benefits compounds this.

History

Discovery → first use → status

  1. 1970VIP isolated from porcine small intestine (Said & Mutt); a 28-amino-acid peptide of the secretin/glucagon superfamily.
  2. 1978Pharmacokinetic/physiologic studies of infused VIP in humans characterize its very short plasma half-life and circulatory effects.
  3. ~2001Synthetic VIP (aviptadil) granted FDA authorization for human trials; later studied in pulmonary hypertension and sarcoidosis.
  4. ~2008-2010Inhaled VIP Phase II trials in pulmonary arterial hypertension (negative) and open-label sarcoidosis (biomarker signal).
  5. 2013Shoemaker open-label case series popularizes intranasal VIP (50 mcg/spray) as the final step of the CIRS / water-damaged-building protocol.
  6. 2020-2021Aviptadil (RLF-100/ZYESAMI) fast-tracked for COVID-19 respiratory failure; sponsor reports a met primary endpoint in one Phase 2b/3 readout amid controversy.
  7. Nov 2021 & 2022FDA declines Emergency Use Authorization for ZYESAMI in critical COVID-19 (twice).
  8. Sept 2023NIH TESICO/ACTIV-3b RCT published in Lancet Respiratory Medicine: no benefit of IV aviptadil, the definitive negative result.
  9. 2026VIP swept up in broader FDA peptide-compounding review; PCAC scheduled to evaluate nominated peptides for the 503A bulk list (July 23-24, 2026).

Verification

The COA standard, applied

Cross-checked the PubMed-indexed Critical Care Medicine RCT (PMID 36044317, primary endpoint NOT significant, OR 1.6, CI 0.86-3.11) and the Lancet Respiratory Medicine TESICO RCT (negative) directly; confirmed FDA twice declined EUA and there is no FDA approval; confirmed half-life via the 1978 human PK study; confirmed the CIRS evidence is small open-label single-network work. Discounted vendor/affiliate peptide sites (peptide catalogs, clinic marketing pages), which uniformly overstate efficacy and omit the negative Phase 3 results.

The full verification standard →

Sources

Where this comes from

The four lenses reflect the evidence and the real-world record as of the last review and will change as data arrives. Real-world signal and reported feedback are anecdote, not proof. Nothing here is medical advice or a prescription.

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