Reconstitution
The process of mixing a lyophilized (freeze-dried) peptide powder with bacteriostatic water to create an injectable solution.
Overview
Peptides are typically shipped as lyophilized (freeze-dried) powder because this form is chemically stable at room temperature for weeks to months. Before use, the powder must be dissolved into a liquid solution — this process is called reconstitution.
The standard solvent is bacteriostatic water (sterile water containing 0.9% benzyl alcohol), which prevents bacterial growth in multi-use vials.
Why Lyophilized Form?
Peptides in aqueous solution are vulnerable to:
- Hydrolysis — water molecules cleave peptide bonds over time
- Oxidation — oxygen degrades certain amino acid residues
- Microbial growth — water is a growth medium for bacteria
Lyophilization removes water entirely, dramatically extending shelf life. Once reconstituted, the peptide is in its active, injectable form but must be refrigerated and used within a few weeks.
The Reconstitution Process
See the full step-by-step guide: How to Reconstitute Peptides.
The key principle: add bacteriostatic water slowly along the vial wall, then swirl gently. Never inject directly onto the powder or shake the vial.
Concentration Calculation
After reconstitution, concentration is expressed in micrograms per milliliter (mcg/mL) or units on an insulin syringe:
- A 5 mg vial reconstituted with 1 mL BAC water = 5,000 mcg/mL = 50 mcg per 10 units on a U-100 syringe
- A 5 mg vial reconstituted with 2 mL BAC water = 2,500 mcg/mL = 25 mcg per 10 units
Use the VialBase Reconstitution Calculator to determine the exact volume for your target dose.
Storage After Reconstitution
| State | Temperature | Stability |
|---|---|---|
| Lyophilized (powder) | Room temperature | Weeks–months |
| Reconstituted | 2–8°C (refrigerated) | 2–4 weeks typical |
| Reconstituted | Frozen | Not recommended — degrades on freeze/thaw cycles |