How to Reconstitute Peptides

Reconstitution is the process of dissolving a lyophilised (freeze-dried) peptide powder into a liquid solvent to create a solution suitable for laboratory use. Research peptides are supplied in lyophilised form because this maximises stability and shelf life during storage and transport. Before use in any laboratory application, the powder must be reconstituted correctly to preserve the peptide's integrity and ensure accurate concentration calculations.

• Lyophilised peptide vial • Bacteriostatic water (BAC water) — available from UK Peptide Lab • Sterile insulin syringe (1ml) • Alcohol swabs • Clean, dust-free work surface Bacteriostatic water contains 0.9% benzyl alcohol as a preservative and is the recommended solvent for most research peptides. It prevents bacterial growth and allows the reconstituted solution to be stored at +4°C for up to 4 weeks.

1. Allow both the peptide vial and the bacteriostatic water to reach room temperature. 2. Wipe the rubber stopper of both vials thoroughly with an alcohol swab and allow to air dry for 30 seconds. 3. Draw the required volume of bacteriostatic water into a sterile syringe. For a standard 5mg vial, 2ml is a common starting point (giving 2.5mg/ml). 4. Insert the needle into the peptide vial at an angle and slowly inject the bacteriostatic water down the inner side of the glass vial wall. Do not inject directly onto the powder. Inject slowly over 10–15 seconds. 5. Gently swirl the vial in a slow circular motion. Never shake — shaking introduces air bubbles and can break peptide bonds. Allow 1–2 minutes for full dissolution. 6. Once reconstituted, store the vial at +4°C (standard refrigerator temperature). Label the vial with the reconstitution date. Use within 4 weeks. Use the UK Peptide Lab reconstitution calculator for instant concentration calculations.

Reconstituted peptides remain stable at +4°C for up to 4 weeks. For longer term storage, draw the solution into multiple small syringes or vials (aliquots) and store at -20°C. This prevents repeated freeze-thaw cycles which degrade peptide quality over time. Never refreeze a vial that has already been thawed and partially used.