Peptide Reconstitution

Research peptides are shipped as a lyophilized (freeze-dried) powder inside a sealed glass vial. In this state they are chemically stable for months at refrigerator temperature. Before they can be drawn into a syringe for laboratory work, the powder must be dissolved into a sterile diluent. This process is called reconstitution.

The diluent of choice is bacteriostatic water (BAC water) — sterile water containing 0.9% benzyl alcohol. The benzyl alcohol suppresses microbial growth, allowing the reconstituted vial to be drawn from multiple times over 28 days without contamination. Sterile water for injection (no preservative) can be used only for single-day work; plain distilled or tap water must never be used.

Gather everything before opening the vial. Work on a clean, flat, non-porous surface.

• Lyophilized peptide vial (sealed)
• Bacteriostatic water — 30 mL multi-dose vial
• U-100 insulin syringes (0.5 mL, 29–31G × 8 mm)
• One 1–3 mL syringe with 21G needle (for BAC transfer, optional)
• Alcohol prep pads (70% isopropyl)
• Sharps disposal container
• Nitrile or latex gloves
• Clean paper towel or absorbent pad

1. 1

   Wash hands

   Warm water, soap, 20 seconds. Dry with a clean towel. Put on gloves.

2. 2

   Prepare surface

   Wipe the work area with a fresh 70% isopropyl pad. Lay down a clean paper towel.

3. 3

   Bring vials to room temperature

   Cold vials can crack when pierced and cause condensation. Allow refrigerated vials to sit at ambient temperature for 10–15 minutes.

4. 4

   Wipe every stopper

   Both the peptide vial and BAC water vial. Fresh alcohol pad on each rubber stopper. Let air-dry — do not blow on it.

5. 5

   Never touch the needle

   Once uncapped, the needle touches only sterile rubber. If it contacts anything else, discard and use a new syringe.

The example below reconstitutes a 10 mg vial with 2 mL of BAC water, yielding a final concentration of 5 mg/mL. Adjust volumes for your specific vial using the math in Section 05.

1. 01

   Inspect the peptide vial

   Confirm the lyophilized cake is intact — a small, dry, disc-shaped puck at the bottom of the vial. If it appears melted, discolored, or the vial seal is compromised, do not use.

2. 02

   Draw the BAC water

   Using a fresh insulin syringe (or a 3 mL syringe with 21G needle), invert the BAC vial and draw the required volume — 2.0 mL for this example. Tap the barrel to bring bubbles to the top, then expel them slowly.

3. 03

   Angle the needle against the vial wall

   Insert the needle into the peptide vial through the center of the stopper. Angle it so the tip touches the inside wall of the glass, above the powder — do NOT squirt water directly onto the cake. Direct impact denatures fragile peptide chains.

4. 04

   Release the water slowly

   Depress the plunger over 5–10 seconds, letting the water run down the glass wall onto the powder. Withdraw the needle.

5. 05

   Dissolve — do NOT shake

   Gently swirl or roll the vial between your palms for 30–60 seconds. Vigorous shaking creates foam and can shear peptide bonds. For stubborn peptides (e.g. GHK-Cu, some GLP-1 analogs), allow the vial to rest for 5–10 minutes; the cake will fully dissolve on its own.

6. 06

   Verify

   Hold the vial to the light. The solution should be clear, colorless (except GHK-Cu which is bright blue), and free of undissolved particles. Any cloudiness, floating debris, or persistent foam means the vial should be discarded.

7. 07

   Label & date

   Write the reconstitution date and final concentration on the vial label with a permanent marker. This is the start of your 28-day storage window.

The concentration after reconstitution is fixed by two numbers: the mg of peptide in the vial and the mL of BAC water you add.

An insulin syringe barrel is marked in units (IU), not mL. On a U-100 syringe, 100 IU = 1.0 mL, so 10 IU = 0.10 mL.

For product-specific tables (Retatrutide, Tirzepatide, GHK-Cu, BPC-157, etc.) refer to each product page — the recommended reconstitution volume and dose range are listed under the specifications panel.

• Never recap a used needle by hand — drop directly into a rigid sharps container.
• One syringe per draw. Insulin syringes are single-use; reusing them dulls the needle and risks contaminating the vial.
• Keep all supplies out of the reach of children and pets.
• Full sharps containers are disposed of at pharmacies, GP surgeries, or via your local council's clinical-waste route (UK).
• Expired or discarded peptide vials should be sealed and placed into clinical/hazardous waste — not household bins.