Vasoactive intestinal peptide is an unapproved drug in the United States, and every practical question about obtaining it follows from that single fact. No finished VIP product has cleared FDA review for any indication, and the synthetic form, aviptadil, has only ever been studied under an open investigational new drug application. What keeps the peptide available at all is an interim enforcement policy on bulk drug substances rather than an approval, and that footing is provisional.
No FDA-approved drug product containing vasoactive intestinal peptide exists in the United States, and its only routine outpatient route is compounding under section 503A while the peptide remains in category 1 of the FDA's interim bulk drug substances policy.
No approved VIP product has ever existed, and the designations that appear in marketing copy do not change that. Sponsor programs for aviptadil have all run under investigational new drug applications, which authorize study in humans rather than sale. The distinction decides what a physician can lawfully write, because off-label prescribing presupposes an approved product to prescribe from in the first place.
Aviptadil has been developed only under investigational new drug applications and holds no FDA marketing authorization, so no lawful off-label use of vasoactive intestinal peptide exists in the United States.
The line is definitional rather than scientific: FDA regulations treat any alpha amino acid polymer of defined sequence longer than 40 residues as a protein, and therefore a biologic, while anything at or below 40 stays on the drug side. At 28 residues, counted along the amino acid backbone rather than by molecular weight, VIP falls on the drug side, which is the only reason the compounding statute reaches it at all.
| Criteria | 40 or fewer amino acids | More than 40 amino acids |
|---|---|---|
| Regulatory class | Drug | Biological product |
| Review pathway | New drug application | Biologics license application |
| Bulk compounding under 503A | Eligible for consideration | Effectively outside the framework |
| Where VIP sits at 28 residues | Here | Not applicable |
Vasoactive intestinal peptide is 28 amino acids long, below the FDA's 40 amino acid threshold, so it is regulated as a drug reviewed through a new drug application rather than as a biologic.
Section 503A gives a bulk active ingredient three ways in, and VIP clears none of them: no approved product contains it, no USP or NF monograph covers it, and it was not placed on the eligible list. What holds the supply open is the interim policy the agency runs while it works through nominated substances. VIP sits in category 1 of that policy, which is enforcement discretion during an open review rather than a settled place on the list.
Vasoactive intestinal peptide meets none of section 503A's three gates for a bulk drug substance and remains compoundable only through category 1 of the FDA's interim policy, a placement the agency can revise on new safety information.
Nothing about the molecules changed in 2023. The FDA finished a long backlog of substances nominated for the 503A list and published its determinations, and a striking number of the peptides that had become staples of integrative practice landed in the category reserved for significant safety concerns. VIP was not caught in that sweep, but the agency's reasoning ran across the class rather than molecule by molecule, which is why category 1 placement reads as provisional rather than safe.
Vasoactive intestinal peptide held its category 1 placement through the 2023 determinations, but the FDA's September 2019 proposed rule had already proposed leaving it off the final 503A list, citing reports of severe immunologic reactions and insufficient evidence of effectiveness.
Two kinds of route exist and they behave nothing alike: one runs through a compounding pharmacy on an ordinary patient-specific prescription, the others through a sponsor that controls the investigational supply and can decline for any reason. Which one is realistic depends far less on the prescriber than on the patient's condition and on a company's willingness to release product.
The only routine outpatient route to vasoactive intestinal peptide is a patient-specific prescription compounded under section 503A, since trial enrollment, expanded access, and right to try all depend on a sponsor's agreement and personal importation is a discretionary FDA policy rather than a lawful supply channel.
The research use only label is a declaration by the seller that the material is not intended for diagnostic or therapeutic use in humans, which makes it a liability shield rather than a quality claim. Vendors operating under it are not registered drug establishments, so current good manufacturing practice requirements, facility inspection, and identity, potency, and impurity testing do not apply to them. Independent testing of peptides bought through these channels has repeatedly turned up product that was underdosed, overdosed, degraded, contaminated with bacterial endotoxin, or not the labeled peptide at all.
A research use only label is the seller's disclaimer of human use rather than a quality standard, and material sold under it carries no sterility assurance, no verified potency, and no lawful pathway into human use.
Aviptadil's development record is the only place VIP has faced sustained regulatory scrutiny, and the result was not a clean one. Larger controlled trials in critical COVID-19 respiratory failure, including a government-sponsored platform trial against placebo in hospitalized patients, did not demonstrate a benefit on the primary endpoint, and no emergency use authorization followed.
The controlled trials of aviptadil in critical COVID-19 respiratory failure did not demonstrate benefit on the primary endpoint and produced no emergency use authorization, leaving VIP without an adequate and well-controlled trial capable of supporting an approval.
Ordering a compounded preparation is legally distinct from writing for a manufactured drug. Section 503A's exemption depends on a valid prescription for an identified individual patient within an established prescriber-patient relationship, which is why office stock ordering and anticipatory batching sit outside the traditional pharmacy exemption and belong to outsourcing facilities instead. Oversight is layered rather than unified, with the FDA governing the substance, state boards of pharmacy licensing and inspecting the compounder, and state medical boards judging the prescriber's conduct.
| Criteria | Approved drug used off label | Never-approved substance |
|---|---|---|
| Legal basis | An existing FDA approval | No approval for any indication |
| Safety profile | Established through review | Not established |
| Literature base | Published body of use data | Thin or absent |
| Consent standard | Routine informed consent | Explicit disclosure of unapproved status and alternatives |
| Liability coverage | Generally covered | Frequently excluded as experimental |
The section 503A exemption holds only for a valid prescription written for an identified individual patient within an established prescriber-patient relationship, and a never-approved substance carries none of the legal scaffolding that supports off-label use of an approved drug.
Educational use only. This article describes what the published scientific and clinical literature reports about Vasoactive Intestinal Peptide. It is not medical advice, and it does not recommend, prescribe, or tell anyone to use anything described here. The regulatory status shown at the top of this page reflects what the record showed on the date given there and can change. mdpep.com does not sell any substance described here, does not endorse human use of it, and does not direct anyone to obtain it.
Talk to a licensed prescriber. Whether a treatment described here is appropriate for you depends on your medical history, your current medications, and the monitoring you may need. A licensed healthcare provider can evaluate your situation.
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Every claim here ties to a named primary source and a date, written as plain documentation with nothing for sale. That is how MD PEP covers the whole peptide market.
