What is the difference between a U-100 and U-40 syringe?

A U-100 syringe holds 100 units per mL (1 unit = 0.01 mL); a U-40 holds 40 units per mL (1 unit = 0.025 mL). The same volume reads a different number of units on each, so always match the calculator to your syringe.

Is there a U-50 syringe?

No. A "50-unit syringe" is simply a 0.5 mL U-100 syringe — it holds 50 units. There is no U-50 insulin concentration.

How much bacteriostatic water should I add?

Any amount works mathematically; more water means a larger, easier-to-measure draw but a more dilute solution. Use the reverse-solve mode to find the BAC water that lands your dose on a round number of units.

Free research tools

Free Peptide Reconstitution Calculator

Free·No sign-up·Instant

Turn vial strength, bacteriostatic water and your target dose into the exact volume and syringe units to draw — with reverse-solve and a visual syringe. Supports U-100 and U-40.

Peptide preset Vial amount

Bacteriostatic water (mL) Target to draw

Desired dose Unit IU

Syringe type Barrel size

Doses per day

Draw to

units

Concentration: /mL
Dose: mg ( mcg) IU
Add BAC water: mL
Doses per vial
Lasts ~: days

/ on a syringe

How to reconstitute a peptide

Enter your vial amount and its unit (mg or IU).
Enter the bacteriostatic water you will add, in millilitres.
Enter your desired dose and choose mg or mcg.
Select your syringe type and barrel size.
Read the millilitres and units to draw, shown on the visual syringe.

Frequently asked questions

What is the difference between a U-100 and U-40 syringe?: A U-100 syringe holds 100 units per mL (1 unit = 0.01 mL); a U-40 holds 40 units per mL (1 unit = 0.025 mL). The same volume reads a different number of units on each, so always match the calculator to your syringe.
Is there a U-50 syringe?: No. A "50-unit syringe" is simply a 0.5 mL U-100 syringe — it holds 50 units. There is no U-50 insulin concentration.
How much bacteriostatic water should I add?: Any amount works mathematically; more water means a larger, easier-to-measure draw but a more dilute solution. Use the reverse-solve mode to find the BAC water that lands your dose on a round number of units.

For research use only. Verify all calculations against current literature and use sterile technique.