Tools
Reconstitution calculator
Enter the vial and the amount you want per draw. It tells you how much bacteriostatic water to add and where that lands on the syringe, so the draw sits on a tick mark. Already mixed? Flip it around and check what a draw holds.
Reconstitution calculator
Pick the vial and the amount you want per draw. It works out the water to add and where that lands on the syringe.
In micrograms. 1 mg is 1,000 mcg.
Syringe
Add to the vial
2.5 mL bacteriostatic water
No volume lands 250 mcg exactly on a mark of this syringe — 2.5 mL comes closest, at 1 units.
Draw
1 units for 250 mcg
- Concentration
- 24 mg/mL
- Per unit
- 240 mcg
- Draws per vial
- 240
One vial lasts about 34.3 weeks (240 full draws) · $1.46 per draw at list price — longer than the typical 28-day in-use window for bacteriostatic mixes
Dose chart for this mix
| Dose | Draw |
|---|---|
| 50 mcg | 0.2 units |
| 100 mcg | 0.4 units |
| 250 mcg | 1 units |
| 500 mcg | 2.1 units |
| 1 mg | 4.2 units |
| 2.5 mg | 10.4 units |
| 5 mg | 20.8 units |
- Under 2 units is hard to measure. Add more water so each draw is larger.
- 24 mg/mL is a very concentrated mix. Check the peptide dissolves fully before drawing.
How the maths works
Everything comes from one relationship: the peptide mass divided by the water you add is the concentration.
Concentration
mg/mL = peptide (mg) ÷ water (mL)
Units to draw
units = amount (mg) ÷ concentration (mg/mL) × 100
What a draw holds
amount (mg) = units ÷ 100 × concentration (mg/mL)
On a U-100 insulin syringe, 100 units is 1 mL, so one unit is 0.01 mL. A 1 mL barrel prints a mark every 2 units; 0.3 and 0.5 mL barrels mark every unit.
Rather than asking how much water you plan to add, the calculator starts from what you know, the vial and the amount per draw, and picks a water volume that puts the draw on a printed mark of your syringe. Tick the override to try your own volume.
Common set-ups
A 250 mcg draw from the four most common vial and water combinations.
| Vial | Water | mg/mL | 250 mcg |
|---|---|---|---|
| 10 mg | 2.0 mL | 5 | 5 units |
| 10 mg | 1.0 mL | 10 | 2.5 units |
| 5 mg | 2.0 mL | 2.5 | 10 units |
| 5 mg | 1.0 mL | 5 | 5 units |
- Draws between 5 and 20 units are the easiest to read. Below 2 units, add more water. Above the syringe capacity, use less.
- Use bacteriostatic water, not plain sterile water, for any vial you will draw from more than once.
- Label the vial with the date and the concentration. The copy button writes that line for you, and the link button shares this exact set-up.
For in-vitro laboratory research only. Not for human or veterinary use. See the catalogue for bacteriostatic water and syringes.