Reconstitution guide

Concentration is vial amount divided by diluent volume. A 10 mg vial reconstituted with 2 ml of bacteriostatic water gives 5 mg/ml. Change the water and you change every number downstream — the vial contents never change, only how dilute they are.

A U-100 insulin syringe is marked in units, not millilitres. One hundred units is 1 ml, so ten units is 0.1 ml. Almost every reported dosing error in this space comes from confusing the two scales.

Bacteriostatic water is directed down the inside wall of the vial rather than sprayed onto the powder, and the vial is swirled rather than shaken. Peptides are fragile molecules and mechanical agitation can degrade them.