How do I calculate peptide concentration?

Divide the amount of peptide in the vial by the volume of water added. A 5 mg vial with 2 mL of water is 2.5 mg/mL, which is 2,500 mcg per mL.

How many units are in 1 mL on an insulin syringe?

A U-100 insulin syringe holds 100 units per mL, so 1 unit is 0.01 mL. A 0.3 mL syringe is marked to 30 units and a 0.5 mL syringe to 50 units.

How do I convert mcg to units?

Work out how many mcg are in one unit (concentration in mcg/mL divided by 100), then divide the amount you want by that figure. At 2,500 mcg/mL one unit holds 25 mcg, so 250 mcg is 10 units.

Does adding more water change the amount of peptide?

No. The total amount in the vial stays the same; more water only makes each unit weaker, so the same amount takes more units to draw.

1 mg is 1,000 mcg (micrograms).

Tool · Reconstitution arithmetic

Peptide calculator

Enter the peptide in the vial, the bacteriostatic water added and the amount per draw. The calculator gives the concentration and how many units that is on a U-100 insulin syringe. It does arithmetic only and does not suggest an amount.

U-100 syringes · 100 units = 1 mL · 1 mg = 1,000 mcg

Draw to

10 units

0.1 mL on a U-100 syringe

Concentration: 2.5 mg/mL
Per unit: 25 mcg
Per 0.1 mL: 250 mcg
Draws per vial: 20

Not medical advice

This tool converts between amounts, volumes and syringe units. It is not a recommendation to use any substance or a guide to how much to use, and it cannot tell you whether a product is what its label says. Check your own figures, and speak to a qualified clinician about anything you intend to take. Disclaimer

How the numbers are worked out

Concentration = peptide in the vial ÷ water added. Multiply mg by 1,000 for mcg.
Per unit = concentration in mcg/mL ÷ 100, because a U-100 syringe has 100 units in 1 mL.
Units to draw = amount per draw ÷ mcg per unit.
Draws per vial = total mcg in the vial ÷ amount per draw, rounded down.

Worked example

A 5 mg vial with 2 mL of water is 2.5 mg/mL (2,500 mcg/mL). Each unit holds 25 mcg, so 250 mcg is 10 units (0.1 mL), and the vial holds 20 draws of that size.

Concentration by vial size and water added

mcg per unit on a U-100 syringe. Read across for more water, down for a larger vial.

Vial	1 mL water	2 mL water	3 mL water
2 mg	20 mcg/unit · 2 mg/mL	10 mcg/unit · 1 mg/mL	6.7 mcg/unit · 0.67 mg/mL
5 mg	50 mcg/unit · 5 mg/mL	25 mcg/unit · 2.5 mg/mL	16.7 mcg/unit · 1.67 mg/mL
10 mg	100 mcg/unit · 10 mg/mL	50 mcg/unit · 5 mg/mL	33.3 mcg/unit · 3.33 mg/mL
15 mg	150 mcg/unit · 15 mg/mL	75 mcg/unit · 7.5 mg/mL	50 mcg/unit · 5 mg/mL
20 mg	200 mcg/unit · 20 mg/mL	100 mcg/unit · 10 mg/mL	66.7 mcg/unit · 6.67 mg/mL

Questions

How do I calculate peptide concentration?: Divide the amount of peptide in the vial by the volume of water added. A 5 mg vial with 2 mL of water is 2.5 mg/mL, which is 2,500 mcg per mL.
How many units are in 1 mL on an insulin syringe?: A U-100 insulin syringe holds 100 units per mL, so 1 unit is 0.01 mL. A 0.3 mL syringe is marked to 30 units and a 0.5 mL syringe to 50 units.
How do I convert mcg to units?: Work out how many mcg are in one unit (concentration in mcg/mL divided by 100), then divide the amount you want by that figure. At 2,500 mcg/mL one unit holds 25 mcg, so 250 mcg is 10 units.
Does adding more water change the amount of peptide?: No. The total amount in the vial stays the same; more water only makes each unit weaker, so the same amount takes more units to draw.
What is 1 mg in mcg?: 1 mg is 1,000 mcg (micrograms).