VIP (Vasoactive Intestinal Peptide)
28-amino-acid neuropeptide; synthetic VIP = aviptadil. Not FDA-approved; aviptadil/phentolamine intracavernosal injection approved in a few regions for erectile dysfunction; IV aviptadil failed in COVID-19 respiratory failure (TESICO).
60-Second Scientific Briefing
VIP (vasoactive intestinal peptide) is a natural 28-amino-acid neuropeptide that relaxes smooth muscle and widens blood vessels; its synthetic form is called aviptadil. It is not approved by the US FDA. An injection combining aviptadil with phentolamine is approved for erectile dysfunction in a few regions. For COVID-19 respiratory failure, the largest randomised trial (TESICO, 461 patients) was stopped for futility, with no improvement over placebo.
What is VIP (Vasoactive Intestinal Peptide)?
Pharmacological Classification & Molecular IdentityVasoactive intestinal peptide (VIP) is a naturally occurring 28-amino-acid neuropeptide; aviptadil is its synthetic form. In nonclinical studies it upregulates lung surfactant production and inhibits cytokine synthesis, which led to its testing in COVID-19 respiratory failure. [1] Crit Care Med, 2022 ↗
Verified Chemical & Regulatory Registry Identifiers
Mechanism of Action & Receptor Targets
Biological Pathway and Target BindingReceptor Selectivity: Acts on VIP receptors to relax smooth muscle and dilate blood vessels; in nonclinical lung studies it increased surfactant production and reduced cytokine release. [1] Crit Care Med, 2022 ↗
Regulatory & FDA Approval Status
Legal and Regulatory ClassificationsNot approved by the US FDA. A 2019 systematic review notes that approval of intracavernosal injection agents for erectile dysfunction is mainly limited to alprostadil, with the addition of an aviptadil/phentolamine combination in a select few geographical regions. [1] World J Urol, 2019 ↗
VIP (Vasoactive Intestinal Peptide) is not approved for commercial sale, prescription therapy, or compounded medication distribution. It exists strictly within authorized scientific and clinical research frameworks.
Human Evidence & Clinical Trials
Clinical Study Readouts and Evidence SynthesesCOVID-19 respiratory failure: TESICO (Lancet Respir Med 2023), 461 patients randomised to intravenous aviptadil or placebo; stopped for futility; odds ratio for a better outcome at day 90 was 1.11 (P=0.54), and 90-day mortality was 38% vs 36%. An earlier US trial (Crit Care Med 2022, 196 patients) missed its primary end point (alive and free of respiratory failure at day 60). Erectile dysfunction: a retrospective study of 308 men who had failed or could not tolerate alprostadil injections (J Sex Med 2025) found the aviptadil/phentolamine injection effective in 59%. [1] J Sex Med, 2025 ↗ [2] Lancet Respir Med, 2023 ↗ [3] Crit Care Med, 2022 ↗
Clinical Evidence
COVID-19 respiratory failure: TESICO (Lancet Respir Med 2023), 461 patients randomised to intravenous aviptadil or placebo; stopped for futility; odds ratio for a better outcome at day 90 was 1.11 (P=0.54), and 90-day mortality was 38% vs 36%. An earlier US trial (Crit Care Med 2022, 196 patients) missed its primary end point (alive and free of respiratory failure at day 60). Erectile dysfunction: a retrospective study of 308 men who had failed or could not tolerate alprostadil injections (J Sex Med 2025) found the aviptadil/phentolamine injection effective in 59%.
Safety Profile & Clinical Limitations
Documented Adverse Events and Known UncertaintiesIn TESICO, the early safety composite (death, serious adverse events, organ failure, serious infection or grade 3–4 events by day 5) occurred in 63% vs 56% with placebo (P=0.10). In the erectile dysfunction series, facial flushing occurred in 22.5% and ischaemic priapism in 0.3%. [1] J Sex Med, 2025 ↗ [2] Lancet Respir Med, 2023 ↗
Benefit for lung, immune or other conditions has not been shown in large randomised trials, and the largest trial was negative. Products sold outside regulated pharmacies have unknown content. [1] Lancet Respir Med, 2023 ↗
Dose Approval Status
Commercial Dosing Status and Policy DirectivesNo dose is approved in the US. Where the aviptadil/phentolamine injection is approved, it is used under specialist supervision according to its local product information. Amounts used in the studies are described in the linked papers and are not a recommendation. [1] J Sex Med, 2025 ↗
Under Egypt Peptides medical governance policies, no personal dosages, titration intervals, cycles, stacking recommendations, or self-injection instructions may be provided for unapproved investigational compounds. Clinical study protocols represent controlled experimental research parameters exclusively.
What is Known vs. What is Unknown
Evidence Comparison and Clinical Evidence Boundaries✓ Confirmed Scientific Evidence
- Vasoactive intestinal peptide (VIP) is a naturally occurring 28-amino-acid neuropeptide; aviptadil is its synthetic form. In nonclinical studies it upregulates lung surfactant production and inhibits cytokine synthesis, which led to its testing in COVID-19 respiratory failure.
- Targets & Selectivity: Acts on VIP receptors to relax smooth muscle and dilate blood vessels; in nonclinical lung studies it increased surfactant production and reduced cytokine release.
- COVID-19 respiratory failure: TESICO (Lancet Respir Med 2023), 461 patients randomised to intravenous aviptadil or placebo; stopped for futility; odds ratio for a better outcome at day 90 was 1.11 (P=0.54), and 90-day mortality was 38% vs 36%. An earlier US trial (Crit Care Med 2022, 196 patients) missed its primary end point (alive and free of respiratory failure at day 60). Erectile dysfunction: a retrospective study of 308 men who had failed or could not tolerate alprostadil injections (J Sex Med 2025) found the aviptadil/phentolamine injection effective in 59%.
- Safety considerations: In TESICO, the early safety composite (death, serious adverse events, organ failure, serious infection or grade 3–4 events by day 5) occurred in 63% vs 56% with placebo (P=0.10). In the erectile dysfunction series, facial flushing occurred in 22.5% and ischaemic priapism in 0.3%.
? Unknown / Under Ongoing Investigation
- Benefit for lung, immune or other conditions has not been shown in large randomised trials, and the largest trial was negative. Products sold outside regulated pharmacies have unknown content.
Verified Questions & Answers
10 Verified scientific answers with permanent anchor keysVIP is a natural 28-amino-acid neuropeptide that relaxes smooth muscle and widens blood vessels. Its synthetic form is aviptadil. It is not FDA-approved.
- The use of IV vasoactive intestinal peptide (aviptadil) in patients with critical COVID-19 respiratory failure: a 60-day randomized controlled trial (Crit Care Med, 2022-11-01)
- Erectile dysfunction: a global review of intracavernosal injectables (World J Urol, 2019-06-01)
It acts on VIP receptors to relax smooth muscle and dilate blood vessels; in laboratory lung studies it raised surfactant production and lowered cytokine release.
No. It is not approved by the US FDA. An aviptadil/phentolamine injection for erectile dysfunction is approved in a few regions.
- Erectile dysfunction: a global review of intracavernosal injectables (World J Urol, 2019-06-01)
In COVID-19 respiratory failure the largest trial (TESICO, 461 patients) was stopped for futility with no benefit; an earlier 196-patient trial missed its primary end point. For erectile dysfunction, a retrospective series of 308 men found the aviptadil/phentolamine injection effective in 59%.
TESICO (Lancet Respir Med 2023): 461 hospitalised adults with COVID-19 acute hypoxaemic respiratory failure (94% in intensive care) received intravenous aviptadil or placebo over 3 days; the data monitoring board stopped the aviptadil comparison for futility; odds ratio for a better day-90 outcome 1.11 (95% CI 0.80–1.55; P=0.54); 90-day mortality 38% vs 36%. Crit Care Med 2022: 196 patients in 10 US hospitals randomised 2:1; the primary end point (alive and free of respiratory failure at day 60) was not met (odds ratio 1.6, 95% CI 0.86–3.11); a secondary survival analysis was reported as favourable. J Sex Med 2025: retrospective single-centre study of 308 men referred after pain from or failure of alprostadil injections; overall 59% resumed penetrative sex (76% in the pain group, 36% in the failure group).
- Intracavernosal injection of aviptadil and phentolamine for refractory erectile dysfunction (308 men) (J Sex Med, 2025-05-10)
- Intravenous aviptadil and remdesivir for COVID-19-associated hypoxaemic respiratory failure (TESICO): a randomised, placebo-controlled trial (Lancet Respir Med, 2023-09-01)
- The use of IV vasoactive intestinal peptide (aviptadil) in patients with critical COVID-19 respiratory failure: a 60-day randomized controlled trial (Crit Care Med, 2022-11-01)
In TESICO the early safety composite occurred in 63% vs 56% with placebo (not statistically significant). With the erectile dysfunction injection, facial flushing occurred in 22.5% and ischaemic priapism in 0.3%.
What are the critical unknown safety aspects and clinical limitations of VIP (Vasoactive Intestinal Peptide)?
§No benefit for lung, immune or other conditions has been shown in large randomised trials; the largest trial was negative. Products sold outside regulated pharmacies have unknown content.
No dose is approved in the US. Where the aviptadil/phentolamine injection is approved, it is used under specialist supervision according to its local product information.
There is no US-approved label; storage of the regionally approved combination follows its local product information.
VIP (aviptadil) is not named on the 2026 WADA Prohibited List. Because approvals differ by region, athletes should confirm its status with their national anti-doping organisation before any use.
- WADA Prohibited List (World Anti-Doping Agency)
What is Egypt Peptides' official medical policy regarding VIP (Vasoactive Intestinal Peptide)?
§Egypt Peptides publishes reviewed scientific reference monographs for documentation and research. The site does not give individual medical advice, preparation or injection instructions, combination protocols or off-label use instructions. Decisions about any medicine belong to the treating physician.
Authoritative Sources & Literature Registry
Regulatory dossiers, clinical trial registries, and published studiesIntracavernosal injection of aviptadil and phentolamine for refractory erectile dysfunction (308 men) ↗
https://pubmed.ncbi.nlm.nih.gov/40192471/
Intravenous aviptadil and remdesivir for COVID-19-associated hypoxaemic respiratory failure (TESICO): a randomised, placebo-controlled trial ↗
https://pubmed.ncbi.nlm.nih.gov/37348524/
The use of IV vasoactive intestinal peptide (aviptadil) in patients with critical COVID-19 respiratory failure: a 60-day randomized controlled trial ↗
https://pubmed.ncbi.nlm.nih.gov/36044317/
Erectile dysfunction: a global review of intracavernosal injectables ↗
https://pubmed.ncbi.nlm.nih.gov/30895359/