What peptide reconstitution means
Many peptides are supplied lyophilized, which means freeze-dried into a powder. The label states how much powder the vial holds, in milligrams. Reconstitution is the step of adding a measured volume of liquid, usually bacteriostatic water, to turn that powder into a solution.
The moment the water goes in, the vial has a concentration: a fixed amount of peptide in every millilitre. Every later measurement depends on that one number, which is why a reconstitution calculator starts there.
The reconstitution concentration formula
Two conversions make that figure easier to use with a syringe:
A U-100 insulin syringe has 100 unit marks per millilitre, so the last line tells you how much one small mark on the barrel holds. The calculator prints all three, and “Show the math” walks through them with your numbers.
BAC water ratio: how water volume changes concentration
The phrase BAC water ratio describes how much water is mixed with how much powder. It is the concentration written the other way up. The table below uses an arbitrary 10 mg vial to show the pattern. It illustrates the arithmetic and is not a suggestion of what to use.
| Water added | Concentration | Per U-100 unit | Total in vial |
|---|---|---|---|
| 1 mL | 10 mg/mL | 100 mcg | 10 mg |
| 2 mL | 5 mg/mL | 50 mcg | 10 mg |
| 3 mL | 3.33 mg/mL | 33.3 mcg | 10 mg |
| 5 mL | 2 mg/mL | 20 mcg | 10 mg |
Two things stand out. The concentration falls as water rises, and the last column never changes. Water volume decides how the contents are spread out, not how much is there. If you want to pick a volume so that a dose lands on a convenient syringe mark, the BAC water calculator does that comparison for you.
Reading the per-mark table
Once a concentration is on screen, the calculator lists what the 5, 10, 20, 25, 50 and 100 unit marks each contain, in mL, mcg and mg. It is a quick reference for record-keeping: if your log says a syringe was drawn to a certain mark, the table shows what that volume held.
Adding a dose is optional. If you enter one, you also get the draw volume and a syringe illustration with the fill line, the same output as the main peptide calculator.
Peptide mixing math: keeping the numbers honest
- Use the label amount. Vial size means the total milligrams printed on the vial, not an amount per dose.
- Use the volume actually added. If 1.8 mL went in rather than 2 mL, enter 1.8. The concentration depends on what is really in the vial.
- Recalculate for every vial. A different vial size or water volume gives a different concentration, even for the same product.
- Keep mcg and mg apart. They differ by a factor of 1,000, which is why the calculator shows both.
The free Peptrack app stores the concentration with each vial in your inventory, so the figure you worked out today is still there on the last draw.
What this reconstitution calculator does not do
- It does not recommend, suggest or verify any dose, schedule or protocol.
- It does not explain how to handle, mix or store a product. Follow the instructions from the manufacturer, your pharmacy or your healthcare provider.
- It does not know what is in your vial, and it has no information about you.
- It does not provide medical advice, diagnosis or treatment.
Results are for research, informational and record-keeping reference only. See the full disclaimer, try the peptide dosage calculator to convert mcg to units, or go back to the Peptrack homepage.
