Compounding Pharmacy Sourcing
Compounding pharmacy sourcing means obtaining a drug prepared by a compounding pharmacy or outsourcing facility rather than as an approved finished product, with no premarket review of that preparation.
United States law creates two compounding categories. A 503A pharmacy compounds for an identified patient against a prescription and is exempt from new drug approval, from good manufacturing practice and from adequate directions for use. A 503B outsourcing facility may compound without patient-specific prescriptions but registers with the FDA and must follow good manufacturing practice. Neither route yields an approved drug: no agency has reviewed the preparation for safety, efficacy or stability.
Compounding a copy of a commercially available drug is generally barred, with a shortage exception that made recent years unusual. Semaglutide and tirzepatide were listed as in shortage from 2022 and a large compounding sector grew around both; the FDA declared those shortages resolved in late 2024 and early 2025 respectively, closing the exception after defined wind-down periods. The agency separately warned in 2023 about compounded products made with semaglutide salt forms, which are not the same active ingredient as the approved base drug.
The distinction that matters clinically is between access and equivalence. A compounded preparation answers price and availability; it asserts no bioequivalence and usually differs in concentration, excipients and container. Those differences propagate: a strength expressed per millilitre rather than in pen units changes what a syringe marking means, and a beyond-use date is not a stability-tested expiry.
The commonest error is reading state pharmacy licensure as federal approval. A licensed pharmacy operating lawfully still produces an unapproved drug, and the licence speaks to the practice rather than the product. A second failure sits upstream: compounding depends on bulk substance bought from suppliers whose registration and testing vary, so a compounder's sterility record cannot vouch for the identity of what it started from.