Peptides 101: How to Open and Reconstitute Peptides

If you’ve just received your first peptide vials, you might be wondering exactly how to prepare them for research use. This straightforward guide will walk you through the process of safely opening and reconstituting lyophilized (freeze-dried) peptide vials.

What You’ll Need

Before starting, gather these supplies:

  • The peptide vial (lyophilized powder)
  • Bacteriostatic water (0.9% sodium chloride with 0.9% benzyl alcohol)
  • Alcohol swabs
  • Insulin syringes (typically 0.5ml or 1ml with 29-31 gauge needles)
  • Optional: larger syringe for bacteriostatic water
  • Clean surface to work on
  • Refrigerator for storage

Step 1: Prepare Your Workspace

Start with a clean, flat surface. Wash your hands thoroughly or use gloves to avoid contamination.

Important: Peptides are delicate compounds. Work in a clean environment away from direct sunlight and heat.

Step 2: Opening the Peptide Vial

Peptide vials typically come with a flip-off cap and a crimp-sealed top. Here’s how to open vials from Simple Peptide:

Flip-Off Cap Vials:

  1. Locate the small plastic cap on top of the vial
  2. Hold the vial firmly on a flat surface or firmly in your hand
  3. Flip the cap off using your thumb (it’s designed to come off easily) – put your thumb under the edge and push up using the meaty part of your thumb
  4. This will expose the rubber stopper underneath
  5. The rubber stopper has a small circle that you’ll inject through
  6. Do not remove the entire metal crimped edge 

Step 3: Reconstituting Your Peptide

Now you’ll add bacteriostatic water to dissolve the peptide powder:

  1. First, determine how much bacteriostatic water to add based on your designed concentration and research needs
  2. Clean the rubber stopper with an alcohol swab and let it dry
  3. Draw the appropriate amount of bacteriostatic water into your syringe
  4. Slowly inject the water INTO THE SIDE of the vial, letting it run down the glass
    • IMPORTANT: Do not inject directly onto the peptide powder as this can damage the peptide structure
  5. Remove the needle, gently swirl or roll the vial (don’t shake vigorously)
    • Shaking creates foam and can damage peptide bonds
    • Swirling/rolling helps the powder dissolve gradually
  6. Continue gently swirling until the solution is completely clear
    • Some peptides dissolve immediately
    • Others may take 5+ minutes of occasional gentle swirling
    • The solution should be clear when fully dissolved

Step 4: Storage After Reconstitution

Once reconstituted:

  1. Store your peptide vial in the refrigerator (2-8°C/36-46°F)
    • Not the freezer – freezing after reconstitution can damage peptides
    • Not at room temperature – this accelerates degradation
  2. Most reconstituted peptides remain stable for about 4-8 weeks when refrigerated
  3. Always check the vial before each use – the solution should remain clear
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