Reconstitution guide
Reconstitution is the process in which a lyophilized (freeze-dried) peptide is mixed with bacteriostatic water (BAC water) to obtain a liquid form ready for laboratory work. It is an inseparable part of preparing research peptides and requires a sterile environment, correct technique and accurate calculation of the solvent volume for the intended concentration.
5 reconstitution steps
The procedure is summarised in five steps; for the complete guide with an explanation of each phase, see the detailed article.
- 1 Sterile workspace preparation. Wipe the working surface with 70% isopropyl alcohol. Tools: lyophilized vial, BAC water, sterile syringe with needle, isopropyl alcohol swab.
- 2 Stopper disinfection. Wipe the rubber stoppers of both vials (peptide + BAC water) with the swab and let dry for 10 seconds — wet alcohol would be pushed inside with the needle.
- 3 Drawing BAC water. Using a sterile syringe, draw the calculated volume of BAC water. Without air bubbles.
- 4 Adding to the peptide vial. Insert the needle at an oblique ~45° angle and let the liquid run down the wall of the vial, not directly onto the peptide pellet. This prevents foaming and denaturation.
- 5 Dissolution. Rotate the vial gently between your fingers (do not shake). The lyophilizate dissolves within 30–60 seconds. After dissolution store in the refrigerator at 2–8 °C.
Most common mistakes
- Shaking instead of rotating. Mechanical shaking can denature peptide structure.
- Adding BAC water too quickly. Liquid hitting the pellet directly causes foaming and degradation of part of the peptide.
- Using sterile water (0.9% NaCl) instead of BAC water. Sterile water has no preservative effect; a peptide in it lasts only 24 hours compared with approximately 28 days in BAC water.
- Storing in the freezer after reconstitution. Repeated freezing and thawing degrades the peptide. After reconstitution it belongs in the refrigerator at 2–8 °C.
- A sealed lyophilized vial stored at room temperature. Even the lyophilizate loses stability — it belongs in the refrigerator at 2–8 °C (short term) or freezer at −20 °C (long-term storage).
Storage
| State | Optimal temperature | Stability duration |
|---|---|---|
| Lyophilizate (sealed vial) | −20 °C long-term / 2–8 °C short-term | 24–36 months at −20 °C |
| After reconstitution with BAC water | 2–8 °C, protect from light | ~28 days (peptide dependent) |
| After reconstitution with sterile water (no BAC) | 2–8 °C | 24 hours |
Note: actual stability duration varies by peptide. Always consult the technical documentation of the specific batch.
BAC water volume
For the prepared concentration a simple relation applies:
BAC water volume (mL) = peptide amount (mg) ÷ desired concentration (mg/mL) Example: 5 mg of peptide dissolved in 2 mL of BAC water gives a concentration of 2.5 mg/mL.
For quick error-free calculation use the Peptide calculator — an interactive tool that computes the solvent volume and per-dose amount based on your experimental protocol.
Continue reading
- Complete guide to lyophilizate reconstitution Deep-dive version of this guide with detailed scientific context (~3,000 words).
- What peptides are and how they are used in research Pillar guide — structure, categorisation, mechanisms and use cases.
- Peptide calculator Interactive calculation of solvent volume and concentration.
- BPC-157 vs TB-500 Comparison of two regenerative peptides — when to choose which.
Frequently asked questions
What is bacteriostatic water?
BAC water is sterile water with 0.9% benzyl alcohol as a preservative. It prevents microbial growth in the reconstituted peptide and extends stability to approximately 28 days.
How long does a peptide last after reconstitution?
In BAC water at 2–8 °C a peptide is typically stable for 28 days. The exact duration depends on the peptide and is stated in the batch technical documentation.
What if I see flakes or cloudiness in the vial after reconstitution?
Discard from further use. Cloudiness indicates aggregation or microbial contamination. Record the batch number and contact the supplier.
Can I freeze a reconstituted peptide?
Not recommended. Repeated freeze-thaw cycles reduce peptide activity. If long-term storage is necessary, aliquot into smaller volumes and freeze once.
What if I do not have BAC water?
Sterile water (0.9% NaCl) is an alternative but stability drops to approximately 24 hours. For longer experimental protocols BAC water is the standard.