Answering the narrow version, because the broad one does not have a single answer. The shortage clause is the answer to the second question and it is a subtraction rather than an addition. Both exemptions forbid compounding something that is essentially a copy of a commercially available approved product. A product FDA has listed as in shortage is not treated as commercially available, so listing removed the objection that otherwise blocked compounding. It never created a permission; it withdrew a prohibition, which is why it evaporated the moment the supply fact changed.
My pharmacy stopped supplying with three weeks notice and a letter that explained nothing, so I went and read the statute.
Two things anyone can check: a state licence number for a 503A, and an FDA outsourcing-facility registration for a 503B. Both are publicly searchable, and a pharmacy unwilling to give you either has answered the question.
What would genuinely help is knowing what actually distinguishes 503A from 503B, in terms of what each may make and from what starting material.
If the honest answer is that nobody knows, that is a useful answer and I would rather have it.
VendorMark said:The shortage clause is the answer to the second question and it is a subtraction rather than an addition.
That is correct as far as it goes, and here is where it stops going. Worth adding the genuine exception, because it is real and narrow: a change made for an identified patient where the prescriber determines it produces a significant clinical difference for that patient. A grid of fixed doses offered to everybody is not that, whatever the intake form says.
PeptideMeter — Independent Peptide Analytics
Community-driven peptide testing and vendor rating platform. Transparent results. Unbiased analysis. Trusted by thousands.
View Resultsalex_tucson said:My pharmacy stopped supplying with three weeks notice and a letter that explained nothing, so I went and read the statute.
This matches mine closely enough to be worth saying so. They are two different exemptions from the same federal requirements and they buy different things. A 503A pharmacy is regulated primarily by the state board, needs a patient-specific prescription, is exempt from CGMP, and may use a bulk substance that has a USP monograph, is a component of an approved drug, or appears on the 503A bulks list — three independent doorways. A 503B outsourcing facility registers with the FDA, is inspected on a risk basis, must comply with CGMP, may compound for office stock without a patient-specific prescription, and has one doorway to a permitted bulk substance: the 503B bulks list, or the drug shortage list.
Clinical perspective, offered as context rather than as advice.
Regarding compounded supply compounding legality: compounding pharmacies can legally produce semaglutide and tirzepatide while these drugs remain on the FDA shortage list. If/when the shortage resolves, the legal landscape may change.
Stay informed. The FDA shortage list is updated regularly. Current status as of my last check: semaglutide partially resolved shortage, tirzepatide still in shortage. This directly impacts compounding availability.