What is the dead space volume in a typical peptide vial and how does it affect dosing?

Standard peptide vials have approximately 0.1-0.2mL dead space that cannot be withdrawn. When calculating total doses, subtract dead space from reconstitution volume. For a 2mg vial in 2mL water (1mg/mL), usable volume is ~1.8-1.9mL, yielding 1.8-1.9mg actual available peptide. USP preparation guidelines address dead volume calculations.