Dr.AddMedPHL said:

Resolution therefore closed the doors unevenly, and the asymmetry follows from the bulks lists.

I read this differently from Dr.AddMedPHL, on substance rather than tone. A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to. It is a different legal universe with no pharmacy oversight, no patient relationship and no content guarantee, and conflating the two in these threads helps nobody.

carl_compliance said:

My pharmacy stopped supplying with three weeks notice and a letter that explained nothing, so I went and read the statute.

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 shortage ongoing, tirzepatide partially resolved. This directly impacts compounding availability.

amsterdam_pete said:

A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to.

Coming at amsterdam_pete’s question from a different direction. The trade-off is reversibility against privacy and there is no option that gives you both. Card payments are reversible and disclose the most; crypto discloses least and is irreversible, which is precisely why pressure toward it is a warning sign when it comes from a seller rather than a buyer. Escrow only means anything where the escrow agent is independent of both parties, which is rarely the case in practice.

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

What actually distinguishes 503A from 503B, in terms of what each may make and from what starting material?

Reporting back.

The bulks-list asymmetry was the piece I had missed entirely. It explains why one of my two pharmacies is still arguing it can supply and the other simply stopped.