Peptide Reconstitution Calculator
Peptides come as lyophilised (freeze-dried) powder. Before injecting, you dilute the powder with bacteriostatic water (BAC water) — this is reconstitution. The ratio of powder to water sets your concentration, which determines exactly how many millilitres you draw for each dose.
How to use
- Enter the total amount of peptide in your vial (check the label).
- Enter how much BAC water you plan to add (or already added).
- Enter your target dose per injection.
Results update instantly. All calculations assume a standard U-100 insulin syringe (100 units = 1 mL).
Your vial
Your dose
Results
Fill in all three fields to see your results
Turn this into a usable protocol
Reconstitution math is step one.
Once you know your draw volume, Staqk helps you keep the rest straight with dose logs, reminders, vial inventory, and compound guides built for peptide and GLP-1 protocols.
What is reconstitution?
Lyophilisation (freeze-drying) extends peptide shelf life and stability during shipping. Before use, you inject bacteriostatic water directly into the vial to dissolve the powder back into a solution — this is reconstitution. The resulting liquid is what you draw into a syringe for subcutaneous injection.
Why does the water volume matter?
The concentration of your reconstituted peptide depends entirely on how much water you add. Less water = higher concentration = smaller injection volumes. More water = lower concentration = larger injection volumes. Most people aim for a concentration that gives a comfortable, easy-to-measure draw — typically 10–30 units on a U-100 syringe.
Understanding syringe units
Insulin syringes are marked in "units" (U). A standard U-100 syringe holds 100 units per mL, so 10 units = 0.1 mL, 50 units = 0.5 mL, and so on. This calculator converts your dose directly to units so you can read the syringe without additional math.
Common peptide reconstitution examples
BPC-157 (5mg vial): add 2.5mL BAC water → 2000mcg/mL. A 250mcg dose = 12.5 units. TB-500 (5mg vial): add 1mL BAC water → 5000mcg/mL. A 2.5mg dose = 50 units. CJC-1295 (2mg vial): add 2mL BAC water → 1000mcg/mL. A 100mcg dose = 10 units. Ipamorelin (2mg vial): add 2mL BAC water → 1000mcg/mL. A 200mcg dose = 20 units. Always use bacteriostatic water — not sterile water — as the benzyl alcohol acts as a preservative, keeping the reconstituted peptide stable for up to 30 days refrigerated.
Frequently asked questions
What is bacteriostatic water? Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol as a preservative. It prevents bacterial growth in multi-dose vials and is the correct diluent for peptide reconstitution. Do not substitute sterile saline or plain sterile water for multi-dose vials.
How much BAC water should I add? This is a personal preference based on your target concentration and injection volume comfort. Most protocols call for enough water to produce a draw volume of 10–30 units per dose on a U-100 syringe — small enough to be comfortable, large enough to measure accurately. Use this calculator to find the water volume that achieves your target.
How long does reconstituted peptide last? Refrigerated reconstituted peptides are generally stable for 28–30 days. Freeze unconstituted powder for long-term storage. Never freeze reconstituted peptide.