Understanding Lyophilized Peptides
lyophilized" class="wiki-gloss-link">Lyophilization (freeze-drying) removes water from peptide solutions under vacuum at low temperature, leaving a dry powder that is stable for long-term storage. Lyophilized peptides are far more stable than liquid solutions, most last 1-3 years frozen in powder form versus 28-30 days reconstituted at 4°C.
What You'll See
Most research peptides arrive as a white or off-white cake or powder in a sealed vial under vacuum or inert gas. Some high-purity peptides are barely visible in the vial. Do not confuse a near-empty vial with a product issue, 5 mg of peptide occupies very little volume.Supplies Required
Before starting, assemble all supplies to avoid mid-process contamination:
- Bacteriostatic water for injection (30 mL vial) - Insulin syringes (U-100 or U-50, 29-31 gauge) - Alcohol swabs (70% isopropyl alcohol) - The peptide vial(s) - Clean surface or sterile gauze to work on
Do NOT use: tap water, drinking water, normal saline (for storage), multi-use syringes, previously used needles.
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Step-by-Step Reconstitution
Step 1: Calculate Your Target Concentration
Decide how many mL of BAC water to add based on your desired concentration. Common convention: 1 mL BAC water per 1 mg peptide = 1 mg/mL solution.Example: 5 mg BPC-157 vial + 2 mL BAC water = 2.5 mg/mL solution. Each 0.1 mL (10 units on U-100 syringe) = 250 mcg.
Step 2: Clean Vial Tops
Swab the rubber septum of both the BAC water vial and peptide vial with a fresh alcohol swab. Allow to air dry 15-30 seconds before inserting needle.Step 3: Draw BAC Water
Using a fresh insulin syringe, draw up the desired volume of BAC water. If adding 1 mL, draw 1 mL into the syringe.Step 4: Inject BAC Water Slowly
This is the most critical step. Insert the needle into the peptide vial at an angle so the BAC water runs down the inside glass wall, do NOT shoot it directly onto the peptide powder. Injecting forcefully onto the powder can physically damage fragile peptide structures. Release the plunger slowly.Step 5: Let It Dissolve, Do Not Shake
Gently swirl or roll the vial between your palms. Do NOT shake, vigorous agitation can denature peptides. Most peptides dissolve within 1-5 minutes. Some (GHK-Cu, Follistatin) may take 10-15 minutes of gentle rolling. The solution should be clear. Mild cloudiness that clears on gentle warming to room temperature is acceptable for some peptides.Step 6: Label and Store
Label the vial with peptide name, concentration, reconstitution date, and expiry (28 days from today). Store at 2-8°C, protected from light. Do not freeze reconstituted peptides.Concentration Calculations
Formula
Concentration (mcg/mL) = [Peptide amount (mcg)] ÷ [BAC water added (mL)]Common Examples
- 5 mg vial + 2 mL BAC water = 2,500 mcg/mL. 100 mcg dose = 0.04 mL = 4 units (U-100 syringe) - 5 mg vial + 2.5 mL BAC water = 2,000 mcg/mL. 100 mcg dose = 0.05 mL = 5 units - 10 mg vial + 2 mL BAC water = 5,000 mcg/mL. 500 mcg dose = 0.1 mL = 10 units - 2 mg vial + 1 mL BAC water = 2,000 mcg/mL (2 mg/mL). 200 mcg dose = 0.1 mL = 10 unitsU-100 Syringe Reference
On a U-100 insulin syringe: 1 unit = 0.01 mL = 10 microliters. 10 units = 0.1 mL. 100 units = 1.0 mL (full syringe).Troubleshooting
Peptide Won't Dissolve
Try: gentle warming in palm for 5-10 min, then slow rolling. If still not dissolving after 15 min: some peptides require a few drops of 0.1% acetic acid added first (IGF-1, Follistatin-344). Check peptide-specific reconstitution guidance.Cloudy Solution
Mild temporary cloudiness that clears, acceptable. Persistent cloudiness or particulate - discard. Aggressive shaking can aggregate proteins; swirl gently.Very Small Amount of Powder Visible
Normal for high-purity peptides. 5 mg of a small peptide (BPC-157, 1,419 Da) occupies minimal volume. Add BAC water as calculated and proceed normally.Powder Sticking to Sides / Cap
This is freeze-drying residue. BAC water will dissolve it from all surfaces with gentle rolling, gently tip the vial to let the solution reach all interior surfaces.References
- [1]United States Pharmacopeia. "Injections and Implanted Drug Products." USP General Chapter <1>.
- [2]ICH Q1A(R2). "Stability Testing of New Drug Substances and Products." International Conference on Harmonisation, 2003.
Key Terms
Bacteriostatic water (BAC water) is sterile water for injection containing 0.9% benzyl alcohol as a preservative. It is …
Subcutaneous injection is the standard administration route for most lyophilized research peptides. The technique is str…
Proper storage is the single biggest factor controlling peptide potency over time. A well-stored lyophilized peptide las…
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