0.1 mL per draw.
Arithmetic only, on the figures entered. It does not suggest an amount, and it cannot tell you whether a peptide should be used at all.
Concentration by vial size and water volume
The same arithmetic, worked out in advance. Each cell is mg per mL, then the units on a 100-unit syringe that hold 100 mcg.
| Peptide in vial | 1 mL water | 2 mL water | 3 mL water |
|---|---|---|---|
| 2 mg | 2 mg/mL · 5 units | 1 mg/mL · 10 units | 0.67 mg/mL · 15 units |
| 5 mg | 5 mg/mL · 2 units | 2.5 mg/mL · 4 units | 1.67 mg/mL · 6 units |
| 10 mg | 10 mg/mL · 1 unit | 5 mg/mL · 2 units | 3.33 mg/mL · 3 units |
| 15 mg | 15 mg/mL · 0.67 units | 7.5 mg/mL · 1.33 units | 5 mg/mL · 2 units |
How the calculation works
Three steps, all division.
- Concentration = peptide in the vial (mg) ÷ water added (mL).
- Volume per draw = amount per draw (mg) ÷ concentration. 1 mcg is 0.001 mg.
- Syringe units = volume per draw (mL) × 100, because a U-100 insulin syringe has 100 units in 1 mL.
Worked through with the calculator’s starting figures: 5 mg in 2 mL is 2.5 mg/mL. 250 mcg is 0.25 mg, and 0.25 ÷ 2.5 = 0.1 mL, which is the 10-unit mark. The vial holds 20 of those.
What the water volume changes
Only the concentration. The amount of peptide in the vial is fixed when it is made, so adding 3 mL instead of 1 mL changes nothing about how much is in there. It spreads it through three times the liquid, so each draw is three times the volume and three times easier to measure.
Too little water pushes the draw down to a few units, where a misread of one mark is a large share of the total. Too much and the draw outgrows a small syringe, and the vial takes more bac water each time. Neither end is wrong in itself. The calculator flags both.
How much bac water to buy
Multiply the water per peptide vial by the number of vials you make up in 28 days. That is the most an opened bottle of bac water will be used for. At 2 mL per vial and two vials a month, 4 mL gets used. A 10 mL vial covers it with some to spare, and a 30 mL bottle would see most of its volume go past its date. Shelf life in detail.
Sizes and suppliers
3 mL, 10 mL and 30 mL vials, who stocks each, and how fast they dispatch.
Where to buy bac water →