How to Reconstitute and Store Peptides: Complete Step-by-Step Guide

Peptides are sold lyophilised (freeze-dried) as a white powder. Before use, they must be reconstituted with sterile liquid. How you do this — and how you store the result — determines whether the peptide remains active. Mistakes at this stage waste your investment and can affect research validity.

What You Need

• Bacteriostatic Water (BAC water) — sterile water with 0.9% benzyl alcohol. The benzyl alcohol prevents bacterial growth, giving reconstituted peptides a 28-day shelf life. Do not use plain sterile water — it has no preservative and spoils rapidly.
• Insulin syringes — 1ml, 29–31 gauge. Precise dosing. Use a new syringe for each injection.
• Alcohol swabs — wipe the vial septum before every needle insertion
• Refrigerator — 2–8°C for reconstituted peptide storage

Step-by-Step Reconstitution

Step 1: Let the lyophilised vial reach room temperature (15–20 min if stored in fridge). Cold powder + cold liquid can cause aggregation.

Step 2: Wipe the vial septum and BAC water vial septum with alcohol swabs. Let dry.

Step 3: Draw your desired volume of BAC water into the insulin syringe. For most peptides, 1ml–2ml is appropriate (see calculation below).

Step 4: Insert the needle into the lyophilised vial and push it to the inside of the glass wall. Let the BAC water run down the inside of the vial slowly — do not squirt it directly onto the powder.

Step 5: Do NOT shake. Gently swirl until powder fully dissolves. The solution should be clear and colourless. If cloudy, it has not fully dissolved — continue swirling gently.

Step 6: Label the vial with the reconstitution date and concentration.

How Much BAC Water to Use

The amount of BAC water determines the concentration:

• 5mg peptide + 1ml BAC water = 5mg/ml (5,000mcg/ml). Each 0.1ml = 500mcg
• 5mg peptide + 2ml BAC water = 2.5mg/ml. Each 0.1ml = 250mcg
• 5mg peptide + 5ml BAC water = 1mg/ml. Each 0.1ml = 100mcg

Choose a concentration that makes your dosing syringe measurements convenient and accurate.

Storage Rules

• Lyophilised (unreconstituted): Room temperature for months, refrigerated for years. Freeze for very long-term storage.
• Reconstituted: Refrigerate at 2–8°C. Use within 28 days. Never freeze reconstituted peptide — ice crystals damage the peptide structure.
• During use: Keep out of direct light. Heat degrades peptides rapidly — never leave in a hot car or near a heat source.

Visual Quality Check

Before each use, inspect the reconstituted solution:

• Should be clear to very slightly yellow — normal
• Visible particles or cloudiness — discard
• Pink or brown colour — degraded, discard