Class
Secretin and vasoactive intestinal peptide belong to the same structural family of gut and neuroendocrine signaling peptides, and between them they hold almost every regulatory position this index tracks. One has approved products and a bulk nomination filed without adequate support. The other has no approved product at all and is nonetheless lawful for a pharmacy to compound today.
Read together they answer a question the rest of the site keeps raising: what actually determines whether a peptide can reach a patient lawfully. It is not the size of the literature, and it is not whether the molecule is endogenous. It is which list the substance is on, and on what date.
Molecules in this class
| Molecule | Class | US status | Position |
|---|---|---|---|
| Vasoactive intestinal peptideVIP; aviptadil | Gut peptides | Compoundable (503A) | Category 1 of the interim 503A bulks list; a pharmacy may compound it while FDA review continues. No approved product containing it exists. |
| SecretinSynthetic human secretin; ChiRhoStim | Gut peptides | FDA-approved | An approved diagnostic drug since 2004, and separately a bulk substance nominated to the 503A list without adequate support; the nomination sits in Category 3. |
VIP; aviptadil
Category 1 of the interim 503A bulks list; a pharmacy may compound it while FDA review continues. No approved product containing it exists.
Synthetic human secretin; ChiRhoStim
An approved diagnostic drug since 2004, and separately a bulk substance nominated to the 503A list without adequate support; the nomination sits in Category 3.
The records are at secretin, approved as a diagnostic agent since 2004, and vasoactive intestinal peptide, the one molecule this index added in 2026 that a 503A pharmacy may lawfully compound. The compoundable and approved pages carry the wider sets.
The 2026 WADA Prohibited List names no member of this class. It does not name Vasoactive intestinal peptide, and that is not the same as permitted: the relevant sections are expressly non-exhaustive, and section S0 covers any substance with no current approval for human therapeutic use.
The vote ledger and the WADA table carry the sources.
Evidence reviews
Reference tables
Definitions