RESEARCH USE ONLYAll information on this page is provided for laboratory research purposes only. These protocols are not medical instructions. Kern Research Laboratories products are not intended for human or animal consumption.
Overview
What is Reconstitution?
Lyophilization (freeze-drying) is the standard method for long-term peptide preservation. The process removes moisture while maintaining structural integrity, producing a stable white powder that can be stored for extended periods at low temperatures.
Reconstitution is the process of dissolving this lyophilized powder back into solution using a suitable aqueous solvent. The resulting solution is what is used in laboratory assays, cell culture work, and other research applications.
Proper reconstitution technique directly affects peptide stability, concentration accuracy, and experimental reproducibility. Errors at this stage — wrong solvent choice, mechanical agitation, incorrect concentration — can compromise an entire research run.
Protocol
Step-by-Step Reconstitution
Follow this protocol in sequence. Each step is critical. Skipping or reordering steps can introduce contamination or degrade the compound.
Gather Your Materials
Before handling the peptide vial, prepare your workspace. You will need: bacteriostatic water (BW) or sterile water for injection (SWFI), a 1 mL or 3 mL syringe with a 25–29 gauge needle, an alcohol swab, and a clean surface or laminar flow hood if available.
Calculate Your Dilution
Determine the concentration you require. The most common convention is 1 mg/mL or 2 mg/mL. Use the formula below to calculate the volume of solvent to add. For example: a 5 mg vial reconstituted with 2.5 mL of bacteriostatic water yields a 2 mg/mL solution.
Swab Both Septa
Using a fresh alcohol swab, wipe the rubber septum of both the solvent vial and the peptide vial. Allow to air-dry for 10–15 seconds. Do not blow on the septa or touch the swabbed area.
Draw the Solvent
Draw the calculated volume of bacteriostatic water into your syringe. Insert the needle through the septum at a slight angle to avoid coring the rubber. Pull back the plunger slowly to avoid introducing air bubbles.
Inject Solvent Into the Peptide Vial
Direct the stream of solvent against the inner wall of the vial — not directly onto the lyophilized powder. This minimizes mechanical disruption of the peptide structure. Add the solvent slowly.
Mix Gently — Do Not Vortex
Once the solvent is added, gently swirl the vial in slow circular motions until the powder is fully dissolved. The solution should appear clear. Never vortex or shake a peptide solution — this can cause aggregation and degradation.
Inspect and Label
Hold the vial up to light and inspect for particulate matter or cloudiness. A properly reconstituted peptide solution should be clear and colourless or slightly yellow depending on the compound. Label the vial with: compound name, batch number, concentration, date reconstituted, and your initials.
Store Correctly
Reconstituted peptide solutions should be stored at 2–8°C (refrigerated) and used within 28 days for bacteriostatic water preparations. Avoid freeze-thaw cycles of reconstituted solutions. Return the vial to refrigeration promptly after each use.
Calculations
Concentration Reference Table
Use the formula: Volume (mL) = Peptide Mass (mg) ÷ Desired Concentration (mg/mL)
| Vial Size | Target Concentration | Add Solvent |
|---|---|---|
| 5 mg | 1 mg/mL | 5.0 mL |
| 5 mg | 2 mg/mL | 2.5 mL |
| 5 mg | 5 mg/mL | 1.0 mL |
| 10 mg | 1 mg/mL | 10.0 mL |
| 10 mg | 2 mg/mL | 5.0 mL |
| 10 mg | 5 mg/mL | 2.0 mL |
Solvent Selection
Choosing the Right Solvent
Solvent choice affects peptide solubility, stability, and shelf life of the reconstituted solution. Most research peptides are soluble in bacteriostatic water. Exceptions are noted in the compound-specific CoA.
Bacteriostatic Water (BW)
0.9% benzyl alcohol in sterile water. The preferred solvent for most research peptides. The benzyl alcohol preservative allows multi-use of the reconstituted vial and extends in-use stability to approximately 28 days at 2–8°C.
Suitable for: Most peptides including BPC-157, TB-500, GHK-Cu, Epithalon
Sterile Water for Injection (SWFI)
Pyrogen-free, additive-free sterile water. Suitable for single-use reconstitution only. No preservative means the reconstituted solution should be used within 24 hours or discarded.
Suitable for: Single-use applications, compounds sensitive to benzyl alcohol
0.9% Sodium Chloride (Normal Saline)
Isotonic saline. Occasionally used for peptides with solubility issues in pure water. Not recommended as a default solvent — consult the specific compound's data sheet.
Suitable for: Specific compounds per data sheet guidance
Acetic Acid (0.1–1%)
Dilute acetic acid is used for peptides that are poorly soluble in neutral pH water, particularly growth hormone-releasing peptides (GHRPs) and some IGF variants. Prepare by diluting glacial acetic acid with sterile water.
Suitable for: GHRPs, GHRH analogues, some IGF peptides
Storage
Storage Requirements
Improper storage is the most common cause of peptide degradation. All KERN RESEARCH LABORATORIES products are shipped lyophilized and sealed under inert atmosphere. Once reconstituted, storage conditions change significantly.
| State | Temperature | Stability Window |
|---|---|---|
| Lyophilized (sealed) | −20°C or lower | 24+ months |
| Lyophilized (opened) | 2–8°C | 6–12 months |
| Reconstituted (bacteriostatic water) | 2–8°C | Up to 28 days |
| Reconstituted (sterile water) | 2–8°C | 24 hours max |
Important: Avoid repeated freeze-thaw cycles of reconstituted solutions. Each cycle introduces thermal stress and can cause aggregation or hydrolysis. If long-term storage of a reconstituted solution is required, aliquot into single-use portions before freezing.
Troubleshooting
Common Errors & How to Avoid Them
Vortexing or shaking the vial
Consequence: Causes peptide aggregation and potential degradation. The solution may appear cloudy.
Correction: Swirl gently only. If cloudiness appears, discard the solution.
Adding solvent directly onto the powder
Consequence: Mechanical disruption can damage tertiary structure in larger peptides.
Correction: Always aim the solvent stream at the inner glass wall of the vial.
Using tap or distilled water
Consequence: Non-sterile water introduces microbial contamination. Distilled water lacks the osmolarity balance of SWFI.
Correction: Use only bacteriostatic water or sterile water for injection.
Reconstituting and storing at room temperature
Consequence: Accelerated degradation. Most peptides have a half-life of hours at room temperature in solution.
Correction: Return to refrigeration (2–8°C) within minutes of use.
Incorrect concentration calculation
Consequence: Errors in dilution will invalidate experimental dosing.
Correction: Double-check using the formula: Volume (mL) = Mass (mg) ÷ Concentration (mg/mL).
Contents
What is Reconstitution?
Step-by-Step Protocol
Concentration Reference
Solvent Selection
Storage Requirements
Common Errors
Materials Checklist
Lyophilized peptide vial
Bacteriostatic water (BW)
1 mL or 3 mL syringe
25–29 gauge needle
Alcohol swabs
Permanent marker / labels
Refrigerator (2–8°C)
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All products sold by KERN RESEARCH LABORATORIES, LLC are intended for research use only. They are not for human consumption, are not FDA approved, and are not supplements or pharmaceutical drugs. These products are not intended to diagnose, treat, cure, or prevent any disease or medical condition. By purchasing from Kern Peptides, you confirm that you are a qualified researcher purchasing these compounds for legitimate in vitro or laboratory research purposes only. You must be 18 years of age or older to purchase.