VIP: research

A blood-vessel and immune signal studied in lung disease; nasal CIRS benefits remain unproven.

Also called: Vasoactive intestinal peptide, Vasoactive intestinal polypeptide, Aviptadil, RLF-100, Zyesami.

Immune peptides · VPAC1 and VPAC2 receptor agonist.

The largest COVID-19 infusion trial found no benefit; small nasal studies lack blinded placebo comparisons. Reports may include the same participants.

Studies

VIP dosage

Typical reported dose: One 50 mcg spray in one nostril, four times a day

  • Three monitored IV infusion days: Day 1: 50 pmol/kg/hour for 12 hours, then Day 2: 100 pmol/kg/hour for 12 hours, then Day 3: 150 pmol/kg/hour for 12 hours one 12-hour infusion daily for 3 successive days, into a vein. Studied in a trial. Studied in: Adults in the cited study. (source)
  • Three monitored IV infusion days: Day 1: 50 pmol/kg/hour for 12 hours, then Day 2: 100 pmol/kg/hour for 12 hours, then Day 3: 150 pmol/kg/hour for 12 hours one 12-hour infusion daily for 3 successive days, into a vein. Studied in a trial. Studied in: Adults in the cited study. (source)
  • India trial: three infusion days: Day 1: 0.166 mcg/kg/hour for 12 hours, then Day 2: 0.332 mcg/kg/hour for 12 hours, then Day 3: 0.498 mcg/kg/hour for 12 hours one 12-hour infusion daily for 3 successive days, into a vein. Studied in a trial. Studied in: Adults in the cited study. (source)
  • Two inhalations 30 minutes apart: 100 mcg in 1 mL, then another 100 mcg in 1 mL after 30 minutes; total 200 mcg/day one daily session with two inhalations, inhaled. Studied in a trial. Studied in: Adults in the cited study. (source)
  • Sarcoidosis: 50 mcg four times daily: 50 mcg by ultrasonic nebulizer four times daily four times daily, inhaled. Studied in a trial. Studied in: Adults in the cited study. (source)
  • Pulmonary hypertension: four inhalations: 50 mcg per inhalation, four times daily; total 200 mcg/day four times daily, inhaled. Studied in a trial. Studied in: Adults in the cited study. (source)

These are doses reported in labels, trials or user reports, not a personal plan. Check the source behind each one.

Work out syringe units with the dosing calculator

VIP side effects and risks

Reported side effects

  • Low blood pressure: IV TESICO: 58.4% versus 41.3% placebo during infusions. Nasal frequency is unknown., serious. Fainting or chest pain needs urgent care; IV trials used infusion pauses or slower rates. (source)
  • Diarrhea: IV TESICO: 39.8% versus 11.3% placebo. US trial: 32.8% versus 1.5%., moderate. Persistent watery stools, poor fluid intake or dizziness need prompt assessment. (source)
  • Flushing: IV TESICO: 14.7% versus 6.1% placebo during infusions., mild (source)
  • Fast heart rate: IV TESICO: 9.5% versus 4.8% placebo during infusions., moderate. A sustained racing or irregular heartbeat, chest pain or faintness needs care. (source)
  • Migraine or headache: Two hour IV challenge in migraine: 15/21, 71%, versus 1/21, 5%, with placebo. Nasal rate is unknown., moderate (source)
  • Raised pancreatic enzyme: Nasal CIRS study: 1/20 had a transient lipase rise without belly pain. This is not a reliable population rate., moderate (source)
  • Nasal fatigue, lightheadedness or no benefit: Mixed forum reports; no denominator or verified product identity., moderate (source)
  • Priapism with the ED combination: VIP–phentolamine cohort: 1/308, 0.3%. This risk concerns penile injections., serious. An erection lasting 4 hours needs emergency care. (source)
  • Severe immune or allergic reactions: FDA’s 2019 review noted severe immune reactions; no reliable rate or route specific denominator was supplied., serious. Swelling of the mouth or throat, wheezing or breathing trouble needs emergency care. (source)

Stop and get help if

  • Fainting, chest pain or severe breathlessness: Stop exposure and seek emergency care.
  • Face or tongue swelling, wheezing or trouble breathing: Seek emergency care for a possible severe allergic reaction.
  • Severe persistent belly pain, repeated vomiting or inability to keep fluids down: Stop exposure and get urgent assessment.
  • An erection lasting 4 hours after penile injection: Seek emergency care immediately; delayed care can damage penile tissue.
  • A sudden severe headache, weakness, speech trouble or vision loss: Seek emergency care immediately.

Who should avoid it

  • pregnant: Pregnancy safety is unproven; trials excluded pregnancy. One favorable case report cannot establish fetal safety.
  • breastfeeding: Breast-milk transfer and infant effects are unknown; clinical trial eligibility excluded breastfeeding.
  • tryingToConceive: Conception safety is unproven. A planned sarcoidosis trial excluded planned pregnancy and required contraception; no tested washout interval is established.
  • under18: Adult trial evidence does not establish child safety. A small CIRS cohort including a minor is insufficient.
  • other: Do not repeat dosing after a serious allergic reaction to VIP or its formulation.
  • other: VIP can lower blood pressure. Existing symptomatic low pressure, fainting or dehydration raises immediate risk.
  • heartCondition: Low blood pressure and faster heart rate can stress the heart; review cardiac status and medicines.
  • uncontrolledBloodPressure: Large blood-pressure changes and interacting medicines need assessment before exposure.
  • pancreatitisHistory: One nasal-study patient had raised lipase. Pancreatitis risk and safe use after pancreatitis are unknown.
  • activeCancer: VIP supports blood-vessel and tumor signaling in lab models. This is a precaution; human cancer risk is unknown.
  • cancerHistory: Discuss prior cancer with the treating team; human recurrence data for added VIP are lacking.
  • other: Two-hour IV exposure provoked migraine; nasal and subcutaneous headache risk is not quantified.
  • kidneyDisease: Dose adjustments are not established. Low pressure or diarrhea may worsen fluid and kidney problems.
  • liverDisease: Formal dose-adjustment studies in liver impairment were not identified.
  • diabetes: VIP can alter glucose and insulin signaling. Glucose response to community schedules is unpredictable.
  • testedAthlete: No VIP-specific anti-doping decision was found; obtain a ruling for the exact substance and product.
  • other: For intracavernosal VIP–phentolamine only: block with sickle-cell disease or trait, multiple myeloma, leukemia, or another condition predisposing to prolonged erections.
  • other: For intracavernosal VIP–phentolamine only: block with penile angulation, cavernosal fibrosis or Peyronie's disease.
  • other: For intracavernosal VIP–phentolamine only: a penile implant is a label contraindication.
  • other: For intracavernosal VIP–phentolamine only: block when an underlying physical disease makes sexual activity inadvisable or contraindicated.
  • other: TESICO IV exclusion: end-stage liver disease prevented enrollment. This trial restriction does not establish a contraindication for nasal or subcutaneous VIP.
  • other: TESICO IV exclusion: severe diarrhea prevented enrollment. Infusion was withheld with more than 3 liquid stools in 24 hours; this restriction is not established for other routes.
  • other: TESICO IV exclusion: current C. difficile infection prevented enrollment. This trial restriction does not establish a contraindication for nasal or subcutaneous VIP.

Interactions

  • Blood-pressure medicines and vasodilators: Nasal VIP interactions are unstudied. Additive blood-pressure lowering is a theoretical concern; intracavernosal VIP–phentolamine has a separate label prohibition on other ED medicines.
  • Insulin and sulfonylureas: VIP affects glucose and insulin biology. A clinical interaction size or routine adjustment is unknown; review glucose monitoring.
  • Anticoagulants: The ED-combination label cautions about bleeding with penile injections. A systemic interaction with nasal VIP has not been established.
  • Other VIP products or analogues: Duplicate VIP exposure can add vascular effects. Long-acting analogues have different kinetics; no dose conversion is established.
  • Other ED medicines with intracavernosal VIP–phentolamine: For intracavernosal VIP–phentolamine only: do not combine with other ED medicines, including oral PDE5 inhibitors or penile injections, because erections may be prolonged.

Product quality risks

  • No independent survey of online VIP products was found. General unauthorized-peptide warnings cannot establish a VIP-specific contamination rate.
  • Unauthorized peptides may contain the wrong amount, the wrong ingredient, microbes, endotoxin or residual chemicals.
  • A research-use label and a high purity percentage do not establish identity, dose accuracy or injection quality.
  • The 2017 authors reported HPLC purity, stability, sterility and endotoxin testing of their nasal formulation; this does not certify other products.
  • FDA’s 2019 review noted risks from wrong-length or wrong-sequence peptides when VIP synthesis is poorly controlled.

How VIP works

VIP attaches to VPAC1 and VPAC2 receptors. It raises a cell signal called cAMP, relaxes some blood vessels and airways, and changes immune-cell activity. These effects explain both its research interest and risks such as low blood pressure.

  • VPAC1 and VPAC2: Activate cAMP signaling in nerve, blood-vessel and immune cells.
  • Blood-vessel and airway muscle: Relaxes muscle; effects depend on the route and exposure.
  • Immune cells: Can lower inflammatory signals and increase regulatory T-cell activity.

Half-life: About 1 minute in plasma after IV infusion in four healthy volunteers.

Gaps: No blinded, independently replicated nasal CIRS efficacy trial was found. The 2013 paper said a blinded study had begun, but a result could not be located. CIRS cohort overlap is unclear. Gene activity and MRI volume changes do not establish cognitive recovery or prevention of dementia. The 2017 paper describes higher dosing both as >7 and >12 sprays/day. No exact maximum or reproducible later titration can be extracted. No controlled human subcutaneous VIP dosing study was found. Long-acting VIP analogues do not validate native VIP injection schedules. Nasal and subcutaneous absorption, long-term rare harms, pregnancy, breastfeeding and child safety remain poorly defined. One pregnancy report and a CIRS cohort including a 14-year-old do not establish safety for pregnancy or minors. The schema has no intracavernosal route. ED label schedules are preserved in regulatory notes and study arms, not misclassified as subcutaneous protocols. The schema lacks molar dose units and day steps. IV trial rates remain in native pmol/kg/hour text; day 1–3 steps all fall in week 1. Published infusion doses and community injections are not interchangeable. There is no validated route-conversion rule. The 196-person US RCT registry and publication differ in enrollment, primary timepoint and outcome counts; publication and registry results were kept distinct. The 2025 ARDS meta-analysis pooled only two RCTs and omitted the 196-person US trial. It also contains invalid-looking reference DOIs and arithmetic errors. Historical endocrine, skin and digestive physiology papers were not exhaustively counted. humanStudies counts the primary human records profiled, not all VIP papers. The 1983 and 1984 seven-person asthma reports appear to overlap; only one was counted. Cohort overlap elsewhere may also inflate report counts. Terminated inhaled trials lack posted numerical results. I-SPY has preliminary sponsor-reported arm counts and futility, but no full peer-reviewed VIP-arm report was verified. The 2010 pulmonary-hypertension conference abstract was located, but exact arm doses and outcome tables were not recovered. The three-person ARDS report contains a 0.98 mcg/kg/hour dose inconsistent with its other case schedules. No protocol was derived from that passage. No standard community cycle, drug holiday or home escalation interval was verified. Relative commonness is qualitative and does not estimate population prevalence. A reported sixteen-spray nasal schedule is secondhand. Since the study maximum is unspecified, whether it exceeds all human exposure cannot be established. No independent marketplace VIP potency, contamination or poison-center dataset was found. VIP-specific 503B eligibility, final-rule follow-through after the 2019 proposal, a relevant FDA warning letter and definitive Canadian or Australian product approval were not verified. No VIP-specific 2026 anti-doping ruling was found. Absence by name is not a clearance decision. Nasal shelf life depends on its formulation and device. The 2017 60-day limit must not be applied to unknown vials or home mixtures. AVISARCO II has a public final report but enrolled no one. It cannot establish safety, efficacy or an inhaled studied maximum. The 2023 five-case ARDS report switches from mcg/kg/hour to mcg/kg/day in one narrative. The discrepancy was retained and no dosing protocol derived. The externally controlled 45-person report has inconsistent diarrhea percentages; raw case counts were retained instead.

Related to VIP

VIP: the short version

Sources

Sources checked: 2026-10-18.

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