503B Outsourcing Facility
Definition
A compounder registered under section 503B, added by the Drug Quality and Security Act in 2013. Unlike a 503A pharmacy it must follow cGMP, is inspected by the FDA on a risk basis, reports adverse events, and may supply without a patient-specific prescription.
Terms used in this definition
Other entries this definition refers to.
What this means for research sourcing
Regulatory status varies by jurisdiction and applies to research supply, not human use. Volta sells to researchers only.
Related Terms in Regulatory
Bulk Drug Substance
The active pharmaceutical ingredient used as a starting material in compounding. Under 503A it may be used only if it meets a USP or NF monograph, is a component of an approved drug, or appears on the FDA's 503A bulks list, and it must arrive with a certificate from a registered manufacturer.
FDA Category 1
In the FDA's review of substances nominated for compounding, the list of those evaluated and found eligible for use as bulk drug substances by 503A and 503B compounders.
FDA Category 2
The list of nominated substances the FDA has flagged with significant safety risks, which are therefore not eligible for compounding while the nomination stands. BPC-157 was placed in this category.
PCAC (Pharmacy Compounding Advisory Committee)
The FDA advisory committee that reviews substances nominated for the compounding bulks lists, weighing the physicochemical characterisation, safety data and historical use before recommending for or against inclusion under 503A and 503B.
Drug Shortage Declaration
An FDA finding that a drug is in shortage, which temporarily widens what compounders may prepare. The GLP-1 SM shortage was declared resolved in February 2025 and GLP-2 TZ in October 2024, which closed that allowance for both.
Class II Recall
The FDA recall class for a product whose use may cause temporary or medically reversible harm, with a remote probability of serious consequences. Every peptide-related recall to date has fallen in this class.
FDA Warning Letter
A published notice telling a company the agency believes it has broken the law, and requiring a written response. Warning letters are public and searchable, which makes them usable primary evidence about a supplier rather than hearsay.
USP (United States Pharmacopeia)
The non-governmental body that publishes public quality standards, called monographs, for drug substances and preparations. US law makes compliance with an applicable monograph a condition of several compounding pathways, and USP <797> covers sterile compounding.
