VIP: uses, evidence and status | Inside Your Peptides

compound file

The answer, first. A 28-amino-acid neuropeptide of the gut, lung and nervous system, first isolated from intestinal extract in the 1970s. The synthetic form is aviptadil. The strongest evidence is for erectile dysfunction, injected into the penis, graded A — approval or replicated trials.

Aviptadil 25 micrograms with phentolamine is a licensed intracavernosal product in a small number of countries ⁷⁹.

In 308 men who had failed other injections, 59% resumed penetrative sex ⁸. The other use — cOVID-19 respiratory failure — grades D or E: a claim the human trials have already tested and not supported.

What it is used for

Every use graded on its own evidence, not the compound as a whole. 4 outcomes, ranked by what the human record supports.

#outcome · human · animal · gradewhat the best evidence actually shows

01Erectile dysfunction, injected into the penislicensed product plus a 308-man series · not the basisgrade AAviptadil 25 micrograms with phentolamine is a licensed intracavernosal product in a small number of countries ⁷⁹. In 308 men who had failed other injections, 59% resumed penetrative sex ⁸.

02Sarcoidosis lung inflammationopen phase 2, n=20 · rodent modelsgrade CFour weeks of nebulised VIP cut tumour necrosis factor alpha production by lavage cells and raised regulatory T cells in 20 patients ³. Open-label, immune markers only, no clinical endpoint measured.

03Pulmonary hypertension2 small studies, n=8 and n=20 · not the basisgrade CInhaled VIP lowered mean pulmonary artery pressure and raised cardiac output in 8 patients ⁴. A 20-patient single-dose study found the vasodilation modest and short-lived ⁵.

04COVID-19 respiratory failurephase 3, n=461 · not the basisgrade EStopped for futility. Day-90 mortality 38% on aviptadil against 36% on placebo, odds ratio 1.11 on the primary ordinal outcome ¹. An earlier 196-patient trial also missed its primary endpoint ².

gradewhat it means

ARegulatory approval, or multiple adequately-powered trials agreeing with each other

BAt least one well-powered human randomised trial, with the direction replicated

CSmall or open-label human trials only

DAnimal or mechanism data only, with no controlled human outcome

EA claim the human trials have already killed

How it works

The proposed mechanism, in three steps. A mechanism is a reason to run a trial, never a substitute for one.

1targetBinds the VPAC1 and VPAC2 G-protein-coupled receptors, carried by airway and vascular smooth muscle and by immune cells ¹⁰.

2signalReceptor coupling raises cyclic AMP, which relaxes smooth muscle and suppresses pro-inflammatory cytokine production ¹⁰.

3effectIn sarcoid lung, four weeks of inhalation cut lavage tumour necrosis factor alpha and expanded CD4 regulatory T cells ³.

What it does not do

Claims the current record does not support. Worth knowing before you set expectations.

not supported by the evidence

Treats mould illness or chronic inflammatory response syndrome. No controlled trial exists. The nasal-spray protocol circulating for this has no randomised evidence behind it at all.
Rescues COVID lungs. A 461-patient phase 3 was stopped for futility ¹, and the inhaled programme was terminated or withdrawn before finishing ¹¹.
Works by mouth or under the skin. Plasma half-time is about one minute ⁶. Every systemic protocol has been intravenous infusion or nebulised, never oral.

How it is used

What published protocols administered, and what the community reports doing. Descriptive on both counts, and never a recommendation.

routeIntravenous infusion and nebulised inhalation in trials. Intracavernosal injection in the licensed product ¹³⁷.

formatSolution for injection or for nebulisation.

published dosesThe licensed erectile-dysfunction product is 25 micrograms aviptadil with 1 or 2 mg phentolamine, injected per episode ⁷. The COVID trial infused 600, then 1200, then 1800 picomoles per kilogram over 12 hours on three consecutive days ¹. Sarcoidosis used nebulised VIP for 4 weeks ³.

human pharmacokineticsPlasma half-disappearance time about one minute after infusion stops, clearance roughly 9 mL per kg per minute ⁶.

reported conventionsAs reported on peptide forums and functional-medicine protocol sheets, 2018-2026: intranasal spray in the microgram range, several doses daily, sustained over months. No published trial has used the intranasal route. Convention, not guidance.

This site does not publish protocols to follow. The doses above are what studies administered or what users report, stated as facts about the literature and the market. How protocols are structured, mixing and storage and the reconstitution calculator cover the arithmetic.

What to expect

Where a trial measured it, the trial. Where only the community reports it, that is said out loud.

onsetIntracavernosal injection works within minutes, which is the whole point of the licensed product ⁷. Inhaled vasodilation in pulmonary hypertension was measured during a single catheterisation and was short-lived ⁵. The sarcoidosis readout came at 4 weeks ³.

most common reportAs reported: flushing. Facial flushing was the commonest adverse event in the 308-man injection series, at 22.5% ⁸.

adverse effectsFacial flushing 22.5% and ischaemic priapism 0.3% across 308 men on intracavernosal aviptadil ⁸. In the COVID phase 3 the composite safety outcome hit 63% on drug against 56% on placebo, not a significant difference ¹.

the stop signalThe licensed product is used per episode, not continuously ⁷. No stop rule exists for the routes the research market uses, because no trial has used them.

Approval and status

What regulators and sport bodies have actually said, separately from what the evidence shows.

approvalLicensed with phentolamine for erectile dysfunction in a few countries. No US approval ⁷⁹.

FDANo US approval. Not named on the FDA list of bulk substances flagged for compounding safety risks ¹².

sport [WADA]Not on the 2026 Prohibited List ¹³.

sold asresearch chemical

Check the vial

The grade above describes a molecule studied under controlled conditions. It says nothing about the powder in a particular vial.

That gap is the one part of this market a reader can actually close. How to read a certificate of analysis covers the five measures in five minutes, and the 2026 audit grades vendors on the documents they publish against a rubric printed in full.

Questions we get

What is VIP used for?

One licensed use: injected into the penis with phentolamine for erectile dysfunction, in a small number of countries ⁷⁹. In research it has been given intravenously for COVID-19 respiratory failure.

That 461-patient phase 3 was stopped for futility ¹. It has also been nebulised in sarcoidosis and pulmonary hypertension, in small studies ³⁴. The research market buys it as a nasal spray, a route no trial has tested.

How is VIP used?

Descriptively, from published protocols. The licensed product is 25 micrograms with phentolamine, injected intracavernosally per episode ⁷. The COVID trial used escalating 12-hour intravenous infusions over three days ¹.

Sarcoidosis used nebulised VIP daily for 4 weeks ³. Plasma half-time is about a minute, which is why every published route is either local or a continuous infusion ⁶.

How long does VIP take to work?

Depends on the route and the target. Injected into the penis it works within minutes ⁷. Inhaled, the pulmonary vasodilation was measurable during a single procedure and faded quickly ⁵.

The sarcoidosis immune changes were read at 4 weeks ³. For the intranasal use the market favours, no trial has measured anything, at any timepoint.

Is VIP an approved drug?

Partly. Aviptadil combined with phentolamine holds marketing approval for erectile dysfunction in a few countries ⁷⁹.

It has no United States approval, and no approval for any lung, immune or fatigue indication. On our index it is graded human [other] on clinical evidence and niche on community adoption. The COVID-19 programme, its highest-profile use, failed in phase 3 ¹.

References

Brown SM, et al. Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA [TESICO]: a randomised, placebo-controlled trial. Lancet Respir Med. 2023. PMID 37348524
Youssef JG, et al. The Use of IV Vasoactive Intestinal Peptide [Aviptadil] in Patients With Critical COVID-19 Respiratory Failure: Results of a 60-Day Randomized Controlled Trial. Crit Care Med. 2022. PMID 36044317
Prasse A, et al. Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosis. Am J Respir Crit Care Med. 2010. PMID 20442436
Petkov V, et al. Vasoactive intestinal peptide as a new drug for treatment of primary pulmonary hypertension. J Clin Invest. 2003. PMID 12727925
Leuchte HH, et al. Inhalation of vasoactive intestinal peptide in pulmonary hypertension. Eur Respir J. 2008. PMID 18978135
Domschke S, et al. Vasoactive intestinal peptide in man: pharmacokinetics, metabolic and circulatory effects. Gut. 1978. PMID 730072
Dinsmore WW, Wyllie MG. Vasoactive intestinal polypeptide/phentolamine for intracavernosal injection in erectile dysfunction. BJU Int. 2008. PMID 18485029
Al-Mitwalli A, et al. Intracavernosal injection of aviptadil and phentolamine for refractory erectile dysfunction. J Sex Med. 2025. PMID 40192471
Duncan C, et al. Erectile dysfunction: a global review of intracavernosal injectables. World J Urol. 2019. PMID 30895359
Dickson L, Finlayson K. VPAC and PAC receptors: From ligands to function. Pharmacol Ther. 2009. PMID 19109992
ClinicalTrials.gov. Registered studies of aviptadil. Accessed 24 August 2026. clinicaltrials.gov
US Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Category 2 lists. fda.gov
World Anti-Doping Agency. The 2026 Prohibited List. In force 1 January 2026. wada-ama.org

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