Research resource
Step-by-step laboratory protocol for reconstituting lyophilised research peptides with bacteriostatic water. Includes worked examples for common vial sizes (5 mg, 10 mg, 30 mg) at multiple target concentrations, the on-site Reconstitution Volume Calculator, and storage best practice. For in-vitro and laboratory research only.
Bacteriostatic water is the standard diluent for research peptides because the benzyl alcohol prevents bacterial growth in the reconstituted solution, extending shelf life. Sterile (non-bacteriostatic) water is also acceptable but the resulting solution should be used more rapidly.
Allow the lyophilised vial to equilibrate to room temperature for 5–10 minutes before opening. This prevents condensation on the cold vial surface, which would introduce moisture into the dry powder.
Wipe the rubber stopper of both the peptide vial and the diluent vial with a 70% isopropanol swab. Allow to air-dry briefly.
Determine the volume of diluent that yields your target concentration. The formula is:
Volume of diluent (mL) = Mass of peptide (mg) ÷ Target concentration (mg/mL)
For convenience use the on-site Reconstitution Volume Calculator - enter the vial mass and target concentration, get the diluent volume directly.
Draw the calculated volume of bacteriostatic water with a sterile syringe. Insert the needle into the peptide vial and inject the diluent slowly down the side wall of the vial - not directly onto the lyophilised cake. Direct impact can cause foaming and degradation of sensitive peptides.
Swirl the vial gently in a circular motion until the lyophilised material is fully dissolved. Do not vortex or shake. Peptide foam exposes the molecule to the air-water interface, which denatures sensitive peptides. Most lyophilised peptides dissolve fully within 30–60 seconds of gentle swirling.
Store the reconstituted solution at 2–8 °C (standard refrigerator temperature). Use within the compound-specific shelf life (typically 14–30 days; light-sensitive compounds like GHK-Cu and melatonin should be stored in amber containers and protected from light).
Diluent volume = 10 mg ÷ 5 mg/mL = 2 mL bacteriostatic water.
Result: a 2 mL stock solution at 5 mg/mL. Each 0.1 mL of the resulting stock contains 0.5 mg of peptide.
Diluent volume = 5 mg ÷ 1 mg/mL = 5 mL bacteriostatic water.
Result: a 5 mL stock solution at 1 mg/mL. Each 0.1 mL contains 0.1 mg of peptide.
Diluent volume = 30 mg ÷ 10 mg/mL = 3 mL bacteriostatic water.
Result: a 3 mL stock solution at 10 mg/mL. Each 0.1 mL contains 1 mg of peptide.
Diluent volume = 60 mg ÷ 20 mg/mL = 3 mL bacteriostatic water.
Result: a 3 mL stock at 20 mg/mL. Useful when more concentrated stocks are needed for downstream serial dilution.
Tip: Higher concentrations (smaller diluent volumes) extend usable shelf life by minimising hydrolysis exposure but make precision pipetting harder. Most laboratory protocols use stock concentrations between 1–10 mg/mL, then serially dilute to working concentrations as needed.
Always check the individual compound page for compound-specific reconstitution and storage notes (each peptide reference page includes a Laboratory Handling section with shelf-life data).
For step 3 of the protocol, the on-site calculator handles the maths automatically.