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How-to · 4 min read

Mixing a vial

Reconstitution, step by step — then let the calculator do the math.

Most peptides arrive as a dry powder (it is far more stable that way). Before use, the powder is dissolved in bacteriostatic water — sterile water with a little benzyl alcohol that keeps the mixed vial clean in the fridge for weeks. This is called reconstitution.

You will need

  • The peptide vial
  • Bacteriostatic (BAC) water
  • Alcohol swabs
  • A syringe to draw the water (a 1ml or 3ml syringe is easiest)

Step by step

  1. Wash your hands and work on a clean surface.
  2. Swab both rubber stoppers — the peptide vial and the water — and let them air-dry.
  3. Draw the water. 2ml is the common default; anywhere from 2ml to 3ml is fine. More water doesn’t mean more compound — it spreads the same amount over more liquid, which makes small doses easier to measure and stings less.
  4. Add it slowly, down the inside wall of the peptide vial — never straight onto the powder.
  5. Swirl gently or roll the vial between your palms until clear. Never shake — it can damage the peptide.
  6. Label it with the date and how much water you added.
  7. Refrigerate (2–8°C / 36–46°F).

The math

Strength = vial size ÷ water added. A 10mg vial with 2ml of water is 5mg per ml. On a standard U-100 insulin syringe, 100 units = 1ml — so the calculator turns any dose into the exact units to draw.

If the solution is cloudy or has particles after mixing, don’t use it.

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