How much bacteriostatic water do I add to a 10 mg ARA-290 vial?

There is no single right amount. More water makes each draw bigger and easier to measure; less water keeps the volume small. With 2 mL, a 10 mg vial is 5 mg/mL, so every 10 units on a U-100 insulin syringe holds 500 mcg. With 1 mL it is 10 mg/mL (1 mg per 10 units). With 3 mL it is 3.33 mg/mL (333.333 mcg per 10 units). With 5 mL it is 2 mg/mL (200 mcg per 10 units).

How many units is 4 mg of ARA-290 from a 10 mg vial?

With 2 mL of water the vial is 5 mg/mL, so 4 mg is 0.8 mL, or 80 units on a U-100 syringe. With a different water volume the units change but the amount does not. The amount is an example for the math, not a recommendation.

How many 4 mg draws are in a 10 mg ARA-290 vial?

2.5 (10 mg ÷ 4 mg), whatever volume of water you add. In practice a little is lost to the syringe dead space and the last drops in the vial.

ARA-290 10 mg Reconstitution: BAC Water & Units

Short answer: 2 mL of bacteriostatic water in a 10 mg ARA-290 vial makes 5 mg/mL. On a U-100 insulin syringe (1 mL = 100 units), every 10 units then holds 500 mcg. More water gives a weaker solution and a bigger draw for the same amount; the amount in the vial stays 10 mg.

Water volume chart for a 10 mg vial

10 mg ARA-290 vial, U-100 insulin syringe.
Water added	Concentration	Per 10 units	Per 1 unit
1 mL	10 mg/mL	1 mg	100 mcg
2 mL	5 mg/mL	500 mcg	50 mcg
3 mL	3.33 mg/mL	333.333 mcg	33.333 mcg
5 mL	2 mg/mL	200 mcg	20 mcg

Syringe units by amount

The amounts below are examples to show the conversion, not doses. How much to take is a decision for you and your prescriber.

Units on a U-100 syringe from a 10 mg vial.
Water added	2 mg	4 mg	8 mg
1 mL	20 units	40 units	80 units
2 mL	40 units	80 units	over 1 mL
3 mL	60 units	over 1 mL	over 1 mL
5 mL	100 units	over 1 mL	over 1 mL

A 10 mg vial holds 5 draws of 2 mg, 2.5 draws of 4 mg, 1.3 draws of 8 mg, no matter how much water you add.

How far a 10 mg vial goes

Draws per vial depend only on the amount per draw, not on the water. The volume and units columns use 2 mL of water (5 mg/mL). Example amounts only, not doses.

10 mg vial: draws, volume and units per example amount.
Amount per draw	Draws per vial	Volume per draw	Units per draw
1 mg	10	0.2 mL	20 units
2 mg	5	0.4 mL	40 units
4 mg	2.5	0.8 mL	80 units
8 mg	1.3	1.6 mL	over 1 mL

Real counts run a little lower: some liquid stays in the syringe and at the bottom of the vial.

The math

Concentration. 10 mg ÷ 2 mL = 5 mg/mL
Volume to draw. amount ÷ 5 mg/mL = mL
Syringe units. mL × 100 = units

For a different water volume or amount, the free peptide reconstitution calculator works backwards from the amount you want and suggests a water volume that lands on a clean syringe mark.

Half-life, time to peak and sources are on the main ARA-290 (Cibinetide) guide.

ARA-290 10 mg reconstitution: how much water and how many units

Water volume chart for a 10 mg vial

Syringe units by amount

How far a 10 mg vial goes

The math

Frequently asked questions