Vasoactive intestinal peptide

Definition

Vasoactive intestinal peptide is a twenty-eight-amino-acid signaling peptide produced throughout the body, most densely in the gut and in the nerves supplying the airways and blood vessels. It relaxes smooth muscle, widens vessels and airways, and modulates inflammation, and it is a natural constituent of human physiology rather than a designed molecule.

The synthetic form used in medicine is called aviptadil. This index tracks the substance because it occupies a position almost nothing else here does: it is lawful for a pharmacy to compound, today, and it has no approved product behind it.

Evidence

Across three name variants PubMed returns 16,022 indexed records, of which 5,810 carry the Humans subject heading, 185 the clinical-trial publication type, and 105 the randomized-controlled-trial type ^[1]. That is a large literature and it is reported here as a magnitude rather than itemized; the twenty-five most relevant randomized records were read to characterize it, and the row on the human trial record says plainly that the individual records were not all opened ^[1]. The publication-type filter was proved live in the same run against a control term returning 8,906 records under the clinical-trial type and 6,115 under the randomized type, the invalid tag returned zero for that control term, and a deliberately invalid record identifier errored in the same run ^[1].

Most of that literature belongs to the endogenous peptide rather than to any product. It divides into headache provocation studies, in which the peptide is infused to see whether it triggers migraine; airway pharmacology, where an early controlled study found that it produced bronchodilation and protected against histamine-induced bronchoconstriction in asthmatic subjects ^[2]; and vascular work.

The largest and most recent randomized evidence concerns aviptadil in respiratory failure, and it is not favorable. A randomized controlled trial in patients with critical COVID-19 respiratory failure reported sixty-day outcomes ^[3]; the National Institutes of Health TESICO platform trial then tested intravenous aviptadil and remdesivir in COVID-19-associated hypoxemic respiratory failure in the United States and published in 2023 ^[4]. A separate randomized clinical trial tested whether the peptide provokes migraine headaches ^[5].

None of that literature concerns the indications the compounded preparation is marketed for. A reader should hold two facts at once: the compounding of this substance is lawful, and the published randomized record supporting the uses it is compounded for is not established here. Lawfulness under section 503A turns on a nomination and a category, not on efficacy, and this molecule is the clearest demonstration on the site that the two questions are separate.

Side effects

No approved product exists, so no FDA label lists the side effects of vasoactive intestinal peptide. The controlled safety data come from trials of its synthetic form, aviptadil, in critically ill patients, and from research infusions of the natural peptide ^{[3, 4, 5]}. No controlled study has examined the compounded preparations for the uses they are sold for.

In the NIH TESICO trial of intravenous aviptadil in COVID-19 respiratory failure, the primary safety outcome, a composite of death, serious adverse events, organ failure, serious infection or grade 3 or 4 adverse events by day 5, occurred in 146 of 231 patients given aviptadil (63%) and 129 of 230 given placebo (56%), a difference that was not statistically significant ^[4]. An earlier randomized trial in 196 patients reported no drug-related serious adverse events ^[3]. Both trials enrolled patients in respiratory failure, so their safety results say little about a healthy adult.

The peptide's action on blood vessels is itself a documented reaction. In a randomized, placebo-controlled crossover trial in 21 people with migraine, a two-hour infusion of the peptide provoked migraine attacks in 15 of them, against 1 after placebo, and widened the superficial temporal artery ^[5].

Educational summary of the cited sources, not medical advice; a prescriber weighs these risks against a person’s own history.

Lawful access

This is the unusual case on this index: there is a lawful route. The section 503A bulks list FDA published May 14, 2026 lists Vasoactive Intestinal Peptide in Category 1, the category for substances under evaluation, and a licensed pharmacy may compound with a Category 1 substance for an individual patient with a valid prescription while that review continues ^[6].

Category 1 is a permission during review, not an approval, and it can end. The same document shows how quickly a position moves: GHK-Cu left Category 1 in April 2026 when its nominators withdrew, and part of it was restored in May ^[6]. A reader relying on this molecule's status should check the date on this page rather than the fact of it.

No approved product exists. Drugs@FDA holds no record of vasoactive intestinal peptide or of aviptadil as the active ingredient of any drug product; in the same session and the same query form, bremelanotide returned one application and liraglutide returned fourteen, and a deliberately invented ingredient name returned none ^[7]. What a patient receives is therefore a pharmacy preparation, which is not reviewed by the FDA for safety, effectiveness or manufacturing quality — the compoundable page sets out what that distinction costs and what it preserves.

This index verifies no seller for this molecule and names none. A lawful status is a necessary condition for a supply route and it is not a sufficient one.

Related molecules

Vasoactive intestinal peptide and secretin are the index's gut peptides and belong to the same structural family, which is why their two records read as a matched pair: one is lawful to compound with no approved product, the other has an approved product and a nomination filed without adequate support. The other Category 1 molecules — sermorelin, NAD+ and glutathione — are collected on the compoundable page, and the nomination tracker shows how few substances reach that category at all.

Elsewhere in this index