Laboratory guide
How to reconstitute research peptides
A laboratory procedure for dissolving lyophilised peptides in bacteriostatic water, calculating concentration and storing the resulting solution.
What you need
Preparation procedure
1. Prepare a clean workspace
Work in a clean laboratory area. Wipe the stoppers of both vials with a fresh alcohol swab and allow them to air-dry before the septum is pierced.
2. Let the peptide reach room temperature
Remove the lyophilised vial from cold storage and allow it to equilibrate to room temperature. Adding cold solvent to a cold vial encourages condensation and can degrade the powder.
3. Measure the diluent
Using a calibrated pipette or a sterile single-use transfer device, measure the volume of diluent the target concentration requires. Bacteriostatic water contains 0.9% benzyl alcohol, which suppresses microbial growth in a vial that will be accessed more than once.
4. Add the diluent slowly down the vial wall
Direct the diluent onto the inside glass wall so it runs down onto the powder rather than striking the lyophilised cake directly. A forceful stream onto the cake can cause foaming and aggregation.
5. Dissolve without shaking
Swirl or roll the vial gently until the solution is completely clear. Do not shake or vortex — agitation can cause aggregation. Full dissolution usually takes under a minute.
6. Label and refrigerate
Label the vial with the peptide, concentration and reconstitution date. Store at 2–8 °C and protect from light. Reconstituted solutions are typically consumed in laboratory work within a few weeks; aliquot if a study requires longer storage.
Dilution reference
Concentration is the vial mass divided by the diluent volume. The table below shows the concentrations produced by common vial-and-volume combinations.
| Vial | Water added | Concentration |
|---|---|---|
| 5 mg | 1 mL | 5000 mcg/mL |
| 5 mg | 2 mL | 2500 mcg/mL |
| 10 mg | 2 mL | 5000 mcg/mL |
| 10 mg | 3 mL | 3333 mcg/mL |
| 20 mg | 3 mL | 6667 mcg/mL |
| 40 mg | 5 mL | 8000 mcg/mL |
Storage and handling
Keep lyophilised vials in a freezer for long-term stock and reconstitute only what a study requires. Once in solution, refrigerate at 2–8 °C, keep the vial out of direct light, and avoid repeated freeze–thaw cycles, which cause aggregation and loss of activity. Discard any solution that becomes cloudy or shows particulates.
Frequently asked questions
- What water should be used to reconstitute research peptides?
- Bacteriostatic water is the standard solvent for multi-use laboratory vials because the 0.9% benzyl alcohol suppresses microbial growth. Sterile water can be used for single-use preparations but offers no preservative.
- How much bacteriostatic water should be added to a vial?
- Volume is chosen to give a convenient concentration rather than a fixed rule. Dividing the vial mass in micrograms by the millilitres of water added gives the concentration in mcg/mL.
- How long does a reconstituted peptide last?
- Once in solution, peptides are far less stable than the lyophilised powder. Stored at 2–8 °C and protected from light, most reconstituted research peptides remain suitable for laboratory use for a few weeks.
- Can a reconstituted peptide be frozen?
- Freezing solutions is generally avoided because freeze–thaw cycles cause aggregation. Long-term stock is best kept as the lyophilised powder in a freezer and reconstituted as required.
Research use only
This guide describes laboratory handling of research materials. Strand products are sold strictly for in vitro and controlled research purposes and are not for human consumption, diagnostic use, or therapeutic application.