AmyNC_wife said:

Do it in two steps and it stops being confusing.

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.

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

How much material I am losing to dead space, and whether that explains why a 10mg vial gives me nine usable draws rather than ten?

Dr.PulmRoch said:

Bacteriostatic water quality matters for dosing arithmetic reconstitution.

Just received my dosing arithmetic order — packaging review:

• Outer box: plain brown, no medication identifiers (discreet) ✅
• Inner insulation: Styrofoam with 2 gel ice packs ✅
• Temperature: vials were cold to touch on arrival ✅
• Labeling: lot number, BUD, compound name, concentration ✅
• Included: COA, reconstitution instructions, dosing card ✅

This is what professional compounding pharmacy shipping looks like. If your order arrives without these basics, reconsider your vendor.

OP back with an update, since a thread like this is useless without one.

Follow-up: it was dead space. Switching to a low-dead-space fixed-needle syringe gave me the tenth dose back.

Dr.AddMedPHL said:

Just received my dosing arithmetic order — packaging review: Outer box: plain brown, no medication identifiers (discreet) ✅ Inner insulation:…

Agreeing with Dr.AddMedPHL, and the qualification matters more than the agreement. The arithmetic is right and one caveat matters: a U-40 syringe changes the markings, not the volumes. If someone hands you U-40 and you read it as U-100 you will be 2.5 times out, and that error has a direction — it is always an overdose.

Correct me if the detail matters more than I have assumed.