From the other side of the consultation, briefly. It helps to ask what evidence would change your mind before you look at any. If nothing would, the discussion is not about evidence, and it is better to say so early than to spend nine posts discovering it.

Worth separating that from compounded supply, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

josh_phd_bmore said:

One practical note: write down what you did and when, before you need it.

Coming at josh_phd_bmore’s question from a different direction. 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.

One concrete data point for the thread. The boring version of this is the one that works, and the boring version is: measure a baseline, change one variable, wait, measure again under the same conditions. Nobody wants that answer and it is still the answer.

One thing that is still open after josh_phd_bmore’s answer:

Why a shortage listing created a legal pathway at all, since a shortage is a supply fact rather than a permission?

Moderator note: the sourcing question belongs in the vendor section and has been split out. Tagging this one for the weekly digest.