Research-use calculator
Reconstitution Dose Calculator
For peptides supplied as lyophilized vials you reconstitute yourself. Working with a prefilled retatrutide pen instead? Use the pen-clicks calculator.
How to use this calculator
- Let the lyophilized vial reach room temperature (15–20 minutes out of the refrigerator).
- Wipe the stoppers of the bacteriostatic-water vial and the peptide vial with an alcohol swab.
- Pick the water volume for the vial strength — 1 mL for 10 mg, 2 mL for 40 mg, 2.5 mL for 50 mg — and confirm the mg/mL and syringe units with this calculator.
- Inject the water slowly down the inner wall of the vial, not onto the powder.
- Swirl gently until fully dissolved — never shake.
- Store the reconstituted vial at 2–8 °C and use within the compound-specific stability window (typically 28 days).
- Discard used syringes in a sharps container; never recap or reuse.
Tap a quick amount above, type a decimal such as 0.25, or use the steppers (0.25 mg steps below 2.5 mg).
Use this when you know the syringe line and want to see the mg amount delivered by the selected mix.
Units to draw
10 units
on a U-100 insulin syringe
Draw 10 units on a U-100 insulin syringe to deliver 1 mg per draw.
Pull the plunger back to the 10-unit mark.
How we calculated this
- Vial strength: 10mg / 1mL = 10mg/mL
- Target amount: 1mg
- Syringe units: 1mg / 10mg/mL x 100 = 10 units
Other amounts using this same mix
These examples use the selected vial strength and water amount above.
| Amount | Syringe line |
|---|---|
| 250 mcg | 2.5 units |
| 500 mcg | 5 units |
| 1 mg | 10 units |
| 2 mg | 20 units |
Reconstitution FAQ
How do I reconstitute a peptide vial?
Add the selected volume of bacteriostatic water to the lyophilized research peptide vial, direct the liquid down the inner wall, then swirl gently until the powder dissolves. Do not shake. The calculator above converts the vial strength and water volume into U-100 syringe units.
How much bacteriostatic water do I add to a peptide vial?
The reference logic auto-recommends 1 mL for 10 mg vials, 2 mL for 40 mg vials, and 2.5 mL for 50 mg vials. Those volumes map common research amounts cleanly onto U-100 syringe marks: 10 mg + 1 mL gives 10 mg/mL, 40 mg + 2 mL gives 20 mg/mL, and 50 mg + 2.5 mL gives 20 mg/mL. You can override to 3 mL when a more dilute mix is needed.
What is a U-100 insulin syringe?
A U-100 syringe is a 1 mL syringe with 100 unit markings. One unit equals 0.01 mL. The calculator assumes this format so the syringe line can be read directly from the concentration math.
How do I calculate mg per unit after reconstitution?
Concentration in mg/mL equals vial strength divided by water volume. Mg per unit equals concentration divided by 100. Example: a 10 mg vial plus 1 mL water is 10 mg/mL, so each U-100 unit contains 0.1 mg, or 100 mcg.
What if the result is more than 100 units?
More than 100 units is more than one full 1 mL U-100 syringe. Recheck the vial strength, water volume, and target research amount before relying on the output. A more concentrated mix uses fewer units for the same mg amount.
How long does a reconstituted vial last?
Bacteriostatic water's 0.9% benzyl alcohol typically supports a 28-day lab-handling window when the reconstituted vial is refrigerated at 2-8 C. Stability varies by compound, so cross-reference the peptide stability and storage guide.
Where can I verify the peptide content of a vial?
Open the COA library to review published certificates, batch IDs, HPLC purity, and verification notes. For a walkthrough, read how to verify a Janoshik COA.