My vial looks cloudy - throw it out?? — 6 month update

Dr.SportsMedIN said:

The shortage clause is the answer to the second question and it is a subtraction rather than an addition.

This is where I part company with the consensus forming above. 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.

A1cHero_PHX said:

Two pharmacies quoted me last year, one describing itself as 503A and one as 503B, and I assumed 503B just meant bigger until both stopped within…

Price comparison for compounded supply across sources I've used:

I use the 503B option — best balance of quality, cost, and legality. The brand price is insane but insurance can help if you qualify.

PharmacoVig_BOS said:

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

I have been on both brand and compounded, and in the context of compounded supply, my experience has been equivalent with both. The key is finding a reliable 503B pharmacy with independent testing.

Following on from andrew_nyc — and this may be the naive question:

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

Closing the loop on my own question.

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.