Explainers
10 pages in this section, most recently updated September 4, 2026.
- 01
503A versus 503B: the two kinds of compounder, in plain English
What sections 503A and 503B of the Food, Drug, and Cosmetic Act actually say, who inspects each kind of compounder, what each may ship and to whom, and why neither produces an FDA-approved drug.
Updated September 4, 2026
- 02
What "essentially a copy" means, and why it decides whether a compounded GLP-1 is lawful
The statutory phrase that separates lawful patient-specific compounding from copying an approved drug: the identical-or-nearly-identical test, the significant-difference exception, the four-prescriptions-a-month reading, and what a prescriber has to document.
Updated September 4, 2026
- 03
The GLP-1 shortage timeline, with every date from an FDA source
When semaglutide and tirzepatide went on FDA's shortage list, when each came off, the October 2024 remand, the 60- and 90-day enforcement discretion windows, and the April 24, 2025 court decision that closed the semaglutide window early.
Updated September 4, 2026
- 04
What a compounding pharmacy may and may not do with GLP-1s now
After the shortage resolutions: the three things FDA says 503A compounders can still do, the things they cannot, the tighter position for 503B facilities, and the questions that tell you which side of the line an offer is on.
Updated September 4, 2026
- 05
What a certificate of analysis shows, and how to read one line by line
A COA is a lab report for one lot. Here is what each section means, which tests matter for an injectable compounded drug, how to match the document to your vial, and the things a COA cannot tell you.
Updated September 4, 2026
- 06
PCAC, the 503A bulks list, and the Category 1 and 2 status of peptides people ask about
How a substance gets onto the 503A bulks list, what Category 1, 2 and 3 meant under the interim policy, which peptides FDA placed in Category 2 in 2023, which were later withdrawn, and what the July 2026 advisory committee did and did not decide.
Updated September 4, 2026
- 07
Salt forms and "research use only": two labels that change what you are buying
Why semaglutide sodium and semaglutide acetate are not the drug in Ozempic, what FDA has said about them, and why a vial marked research use only is a chemical sale with no pharmacy, no prescriber and no exemption behind it.
Updated September 4, 2026
- 08
Who inspects a compounding pharmacy, and how to read what they found
State boards, FDA, and the documents each produces: inspection reports, Form 483 observations, warning letters, recalls, consent decrees. What each one means, where it is published, and how to search for a specific pharmacy.
Updated September 4, 2026
- 09
How to report a problem with a compounded drug to FDA MedWatch
Which form to use (3500B is the one written for patients), where the online form is, the phone line, what to have ready before you start, and who else to tell: the pharmacy, the prescriber and the state board.
Updated September 4, 2026
- 10
How to use the pharmacy vetting checklist
Ten answers in, a printable list of verification steps out. What each question is really asking, why the tool never scores an offer, and how to work through the list in an afternoon.
Updated September 4, 2026