How peptide reconstitution works
Most research peptides ship as a freeze-dried (lyophilized) powder inside a sealed vial. Before you can dose, you mix the powder with bacteriostatic water (BAC water) — sterile water with 0.9% benzyl alcohol that suppresses bacterial growth during multi-use storage. The amount of BAC water you add determines the concentration, and the concentration determines how many units on an insulin syringe equal a single dose.
For example: a 5 mg BPC-157 vial reconstituted with 2 mL of BAC water yields 2.5 mg/mL. A 250 mcg dose is 0.1 mL — 10 units on a U-100 insulin syringe.
BAC water vs sterile water
BAC water is preferred for peptides used over several days or weeks because the preservative keeps the reconstituted solution stable. Plain sterile water has no preservative and is suitable only for single-use reconstitution.
Dose conversion (mg ↔ mcg ↔ IU)
1 mg = 1,000 mcg. International units (IU) only apply to specific peptides such as HGH— the IU-to-mg ratio varies by product. For mass-based peptides like BPC-157, TB-500, or Semaglutide, stick to mg or mcg.
Storage
Refrigerate reconstituted vials at 2–8 °C. Most peptides are stable for 4–8 weeks once mixed; verify the specific peptide's stability profile on its individual page.