Peptide Reconstitution Calculator
Enter the amount of peptide in the vial and the volume of bacteriostatic water to add. The calculator returns the concentration in mg/mL and mcg/mL, the volume to withdraw on a U-100 insulin syringe for a target amount, and how many draws a vial contains.
By the Dynamite Research Team · Updated July 8, 2026
To measure 250 mcg, withdraw
5.0 units
on a U-100 insulin syringe · = 0.050 mL
A U-100 insulin syringe is graduated so that 100 units = 1 mL. This tool performs reconstitution arithmetic only, for laboratory reference. It is not medical or dosing advice.
How the math works
Concentration. Reconstitution concentration is simply the peptide mass divided by the diluent volume. Adding 10 mg of peptide to 2 mL of bacteriostatic water gives 5 mg/mL, which is 5,000 mcg/mL.
Draw volume. To measure a target amount, divide it by the concentration. A 250 mcg target at 5,000 mcg/mL is 0.05 mL.
Syringe units. A U-100 insulin syringe reads 100 units per mL, so 0.05 mL is 5 units. The amount of water changes the concentration and the units per draw, but never the total peptide in the vial.
Worked example: 10 mg vial
| Water added | Concentration | 250 mcg draw | Draws / vial |
|---|---|---|---|
| 1 mL | 10 mg/mL (10,000 mcg/mL) | 2.5 units (0.025 mL) | 40 |
| 2 mL | 5 mg/mL (5,000 mcg/mL) | 5 units (0.05 mL) | 40 |
| 3 mL | 3.33 mg/mL (3,333 mcg/mL) | 7.5 units (0.075 mL) | 40 |
Note that the number of draws per vial (40) is identical regardless of the water volume — only the draw size changes.
Frequently Asked Questions
How do you calculate peptide reconstitution?
Divide the peptide amount by the volume of bacteriostatic water to get the concentration. For example, 10 mg of peptide reconstituted with 2 mL of bacteriostatic water gives 5 mg/mL, which is 5,000 mcg/mL. To find the volume for a target amount, divide the target (in mcg) by the concentration (in mcg/mL).
How many units on an insulin syringe is my draw?
A U-100 insulin syringe is graduated so that 100 units equals 1 mL. Multiply the volume to withdraw (in mL) by 100 to get units. For example, 0.05 mL equals 5 units on a U-100 syringe.
How much bacteriostatic water should I add to a peptide vial?
The amount of bacteriostatic water is a matter of convenience — it changes the concentration but not the total amount of peptide in the vial. More water gives a lower concentration and larger, easier-to-measure draw volumes; less water gives a higher concentration. Common choices are 1–3 mL per vial. Use the calculator to see how each volume changes the concentration and the units per draw.
What is the concentration in mcg per mL?
Concentration in mcg/mL equals the concentration in mg/mL multiplied by 1,000. So 5 mg/mL is 5,000 mcg/mL. The calculator shows both automatically.
How many draws are in one vial?
Divide the total amount of peptide in the vial (in mcg) by the target amount per draw (in mcg). For example, a 10 mg (10,000 mcg) vial measured in 250 mcg draws yields 40 draws, regardless of how much water was used to reconstitute it.
Is bacteriostatic water the same as sterile water?
No. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows a multi-use vial to be accessed repeatedly over time. Sterile water has no preservative. In research handling, bacteriostatic water is the common diluent for multi-use reconstitution.
This calculator performs reconstitution arithmetic for laboratory reference only. It does not constitute medical, veterinary, or dosing advice. All products are sold strictly as research reference material for in-vitro laboratory research use only — they are not drugs, foods, or dietary supplements, are not for human or veterinary use, and are not FDA-approved for any medical use.