How much bacteriostatic water do I add to a 20 mg BPC-157 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 20 mg vial is 10 mg/mL, so every 10 units on a U-100 insulin syringe holds 1 mg. With 1 mL it is 20 mg/mL (2 mg per 10 units). With 3 mL it is 6.67 mg/mL (666.667 mcg per 10 units). With 5 mL it is 4 mg/mL (400 mcg per 10 units).

How many units is 250 mcg of BPC-157 from a 20 mg vial?

With 2 mL of water the vial is 10 mg/mL, so 250 mcg is 0.025 mL, or 2.5 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 250 mcg draws are in a 20 mg BPC-157 vial?

80 (20 mg ÷ 250 mcg), whatever volume of water you add. In practice a little is lost to the syringe dead space and the last drops in the vial.

BPC-157 20 mg Reconstitution: BAC Water & Units

Short answer: 2 mL of bacteriostatic water in a 20 mg BPC-157 vial makes 10 mg/mL. On a U-100 insulin syringe (1 mL = 100 units), every 10 units then holds 1 mg. More water gives a weaker solution and a bigger draw for the same amount; the amount in the vial stays 20 mg.

Water volume chart for a 20 mg vial

20 mg BPC-157 vial, U-100 insulin syringe.
Water added	Concentration	Per 10 units	Per 1 unit
1 mL	20 mg/mL	2 mg	200 mcg
2 mL	10 mg/mL	1 mg	100 mcg
3 mL	6.67 mg/mL	666.667 mcg	66.667 mcg
5 mL	4 mg/mL	400 mcg	40 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 20 mg vial.
Water added	125 mcg	250 mcg	500 mcg
1 mL	under 2 units	under 2 units	2.5 units
2 mL	under 2 units	2.5 units	5 units
3 mL	under 2 units	3.8 units	7.5 units
5 mL	3.1 units	6.3 units	12.5 units

A 20 mg vial holds 160 draws of 125 mcg, 80 draws of 250 mcg, 40 draws of 500 mcg, no matter how much water you add.

How far a 20 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 (10 mg/mL). Example amounts only, not doses.

20 mg vial: draws, volume and units per example amount.
Amount per draw	Draws per vial	Volume per draw	Units per draw
62.5 mcg	320	0.006 mL	under 2 units
125 mcg	160	0.013 mL	under 2 units
250 mcg	80	0.025 mL	2.5 units
500 mcg	40	0.05 mL	5 units
1 mg	20	0.1 mL	10 units

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

20 mg next to other BPC-157 vial sizes

To get the same 10 mg/mL from another vial size, scale the water with the vial. Same strength means the same units for the same amount, whichever vial it comes from.

Water for 10 mg/mL, and 250 mcg draws per vial, by vial size.
Vial	Water for 10 mg/mL	250 mcg draws per vial
2 mg	0.2 mL	8
5 mg	0.5 mL	20
10 mg	1 mL	40
15 mg	1.5 mL	60
20 mg (this page)	2 mL	80

The math

Concentration. 20 mg ÷ 2 mL = 10 mg/mL
Volume to draw. amount ÷ 10 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.

Other BPC-157 vial sizes: BPC-157 2 mg · BPC-157 5 mg · BPC-157 10 mg · BPC-157 15 mg

Half-life, time to peak and sources are on the main BPC-157 guide.

BPC-157 20 mg reconstitution: how much water and how many units