Why Peptides Come as Powder
Most injectable therapeutic peptides are supplied in lyophilized (freeze-dried) form — a white powder in a sealed vial. Lyophilization extends shelf life significantly compared to liquid formulations. The peptide must be reconstituted (dissolved) in sterile liquid before injection.
What Is Bacteriostatic Water
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol inhibits bacterial growth, allowing the reconstituted peptide to remain stable for up to 28-60 days under refrigeration. Using regular sterile water is not appropriate for multi-dose vials because it does not inhibit bacterial contamination after the vial is first opened.
The Reconstitution Process
Your physician or support team will walk you through the complete process before you begin. The general steps involve drawing a specific volume of bacteriostatic water into an insulin syringe, injecting it slowly down the side of the vial (not directly onto the powder), allowing the powder to dissolve without shaking, and then calculating your dose based on the resulting concentration.
Storage After Reconstitution
Reconstituted peptides must be stored refrigerated (2-8°C / 36-46°F). They should not be frozen. Stability varies by compound — your physician will advise on the specific stability window for your medication. Protect from light by keeping in the original box or wrapping in foil.