Reconstitution math, start to finish.
Vial mg divided by the millilitres of bacteriostatic water you add gives the concentration in mg per mL. That single number is what every later conversion depends on.
The direct answer
Concentration equals vial mg divided by water mL. Nothing about the powder changes the arithmetic: the mass in the vial is fixed, and the water you add decides how concentrated the result is.
mg/mL = vial mg ÷ water mL
A 30 mg vial with 3 mL of water gives 10 mg/mL, so 10 units on a U-100 syringe contains 1 mg. The same 30 mg vial with 1.5 mL gives 20 mg/mL, and that identical 10 unit mark now holds 2 mg.
This page is arithmetic only. It converts numbers you already have from the vial in front of you and the prescription you were given. It does not tell you how much water to add, how much to take, or how often. Those are medical decisions for a licensed clinician who knows your history.
Five worked reconstitutions
30 ÷ 3 = 10 mg/mL. One unit on a U-100 syringe is 0.01 mL, so it holds 0.1 mg at this concentration.
18 ÷ 2 = 9 mg/mL. One unit on a U-100 syringe is 0.01 mL, so it holds 0.09 mg at this concentration.
70 ÷ 2 = 35 mg/mL. One unit on a U-100 syringe is 0.01 mL, so it holds 0.35 mg at this concentration.
17 ÷ 2 = 8.5 mg/mL. One unit on a U-100 syringe is 0.01 mL, so it holds 0.085 mg at this concentration.
1 ÷ 1 = 1 mg/mL. One unit on a U-100 syringe is 0.01 mL, so it holds 0.01 mg at this concentration.
Reference table: concentration in mg per mL
Vial mass down the side, water added across the top. Every cell is the vial divided by the water.
| Vial | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 1 mg | 1 mg/mL | 0.5 mg/mL | 0.333 mg/mL | 0.2 mg/mL |
| 5 mg | 5 mg/mL | 2.5 mg/mL | 1.667 mg/mL | 1 mg/mL |
| 10 mg | 10 mg/mL | 5 mg/mL | 3.333 mg/mL | 2 mg/mL |
| 17 mg | 17 mg/mL | 8.5 mg/mL | 5.667 mg/mL | 3.4 mg/mL |
| 18 mg | 18 mg/mL | 9 mg/mL | 6 mg/mL | 3.6 mg/mL |
| 30 mg | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
| 70 mg | 70 mg/mL | 35 mg/mL | 23.333 mg/mL | 14 mg/mL |
Half a barrel, drawn
Questions people actually type
When 30 mg of peptide are reconstituted with 3 mL of water, how many mg per mL?
10 mg/mL. Thirty milligrams divided by three millilitres is ten milligrams per millilitre. On a U-100 syringe, where 100 units is 1 mL, one unit of that solution holds 0.1 mg, and 10 units holds 1 mg.
An 18 mg peptide bottle with 2 mL of bacteriostatic water will be how many mg per mL?
9 mg/mL. Eighteen divided by two is nine. That means 10 units on a U-100 syringe, which is 0.1 mL, contains 0.9 mg, and a 1 mg amount would read 11.1 units.
How do you convert peptide powder to liquid, for example 70 mg to mL?
A mass does not convert to a volume on its own. Seventy milligrams of powder becomes a volume only once you choose how much bacteriostatic water to add, and that choice belongs to the prescription you were given. Adding 2 mL to a 70 mg vial gives 35 mg/mL; adding 5 mL to the same vial gives 14 mg/mL.
What does a 17 mg per 500 mcg per mL (2 mL) label mean?
It is describing a vial of 17 mg reconstituted to 2 mL, which is 8.5 mg/mL, alongside a 500 mcg reference amount. Five hundred micrograms is 0.5 mg, and at 8.5 mg/mL that is 0.059 mL, which reads about 5.9 units on a U-100 syringe.
What is the 1 mg per 1 mL standard format?
It is the simplest case: one milligram of peptide dissolved in one millilitre of liquid, so the concentration is 1 mg/mL. Because 100 units is 1 mL on a U-100 syringe, 1 mg reads as the full 100 units, and 0.1 mg reads as 10 units.
Does 2 mcg into 100 mL give a 20 mcg per mL solution?
No. Two micrograms spread through 100 millilitres is 0.02 mcg/mL, which is a thousand times weaker than 20 mcg/mL. To reach 20 mcg/mL in 100 mL you would need 2000 mcg, which is 2 mg. Dividing mass by volume is the whole operation.
Related conversions
Worked vial cases
Run your own numbers
The free web calculator takes your vial, your water, and your amount, and shows every step of the conversion. Nothing is stored and no account is needed.