From the other side of the consultation, briefly.

Bacteriostatic water quality matters for dosing arithmetic reconstitution. Not all BAC water is created equal:

• Should contain 0.9% benzyl alcohol as preservative
• Must be sterile and pyrogen-free
• Should come in a sealed, intact vial
• Check expiration date — yes, BAC water expires
• Store at room temperature, protected from light

I buy from a reputable medical supply company, not Amazon marketplace sellers. The $3 savings isn't worth the infection risk from unverified BAC water.

kate.chem said:

Comparison of compounded dosing arithmetic delivery formats I've tried: Format Pros Cons Lyophilized vial Longest shelf life, lowest cost Requires…

Coming at kate.chem’s question from a different direction. Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion. Synthesis, testing, and cold-chain shipping have floors. A price well under the floor means something was skipped, and the two things that get skipped are testing and content.

kate.chem said:

Comparison of compounded dosing arithmetic delivery formats I've tried: Format Pros Cons Lyophilized vial Longest shelf life, lowest cost Requires…

Regarding dosing arithmetic multi-dose vial contamination prevention: after reconstituting, I wipe the vial stopper with a fresh alcohol swab before EVERY single draw. I also never touch the stopper with my fingers and use a new needle for each draw.

Even with bacteriostatic water preservative, contamination is cumulative. One sloppy draw can introduce bacteria that multiply over days. Aseptic technique isn't optional — it's essential for injectable medications.

Following on from kate.chem — and this may be the naive question:

How people are distinguishing a supplier having a bad batch from a supplier on the way out?

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful.