Research Peptide Reconstitution & Storage Guide

Research-grade peptides are supplied in lyophilised (freeze-dried) form for good reason: the removal of water significantly extends shelf life and chemical stability. Peptide bonds and secondary structures are susceptible to hydrolysis and oxidation in aqueous solution; in lyophilised form, these degradation pathways are essentially arrested. Proper reconstitution and storage of the resulting solution is critical to preserving the compound's integrity for research use.

• Bacteriostatic water (BW) — 0.9% benzyl alcohol in sterile water. The preservative inhibits microbial growth, extending reconstituted solution stability to 4–6 weeks at refrigeration temperature. Do not use plain sterile water for multi-use vials as it lacks antimicrobial protection.
• Insulin syringes — for accurate small-volume withdrawal (typically 29–31G, 0.5–1mL capacity)
• Alcohol swabs — clean vial stoppers before and after insertion
• Cold storage — a dedicated section of a standard laboratory refrigerator (2–8°C) for reconstituted vials; −20°C freezer for lyophilised stock

1. Allow lyophilised vial to reach room temperature before opening (reduces condensation risk)
2. Wipe the rubber stopper with an alcohol swab and allow to air dry
3. Draw the desired volume of bacteriostatic water into a syringe
4. Insert the needle at an angle and inject slowly along the glass wall of the vial — do not aim directly at the lyophilised cake, as this causes foaming and potential peptide denaturation
5. Remove the syringe and gently swirl the vial in a circular motion until fully dissolved — this may take 30–60 seconds
6. Do not vortex, shake vigorously, or apply heat
7. The solution should be clear and colourless; discard if cloudy or particulate matter is visible
8. Label the vial with compound name, concentration, reconstitution date, and expiry date (4–6 weeks)

To determine the volume of bacteriostatic water required for your target concentration:

Formula: Volume (mL) = Peptide mass (mg) ÷ Target concentration (mg/mL)

Examples:

• 10mg peptide at 2mg/mL → add 5mL bacteriostatic water
• 20mg peptide at 5mg/mL → add 4mL bacteriostatic water
• 30mg peptide at 3mg/mL → add 10mL bacteriostatic water

Higher concentrations reduce injection volumes but increase the osmolality of the solution. Most GLP-1 class peptides in research protocols are reconstituted at 1–5mg/mL. Confirm the appropriate concentration for your specific protocol before proceeding.

Avoid storing peptide solutions near the refrigerator door (temperature fluctuation) or in proximity to strong oxidising agents. Repeated freeze-thaw cycles accelerate degradation and should be avoided.