Peptide reconstitution calculator
Work out the concentration and how many units to draw on an insulin syringe.
Units to draw
10units
- Concentration
- 2.5 mg/mL
- per unit
- 25 mcg
- Volume per dose
- 0.1 mL
- Doses per vial
- ~2
How reconstitution works
Reconstitution is just dissolving a freeze-dried (lyophilised) peptide in bacteriostatic water so you can measure it accurately. The amount of peptide doesn't change — adding more water only spreads the same milligrams across a larger volume, which lowers the concentration and means you draw more units for the same dose.
The math
Concentration (mg/mL) = vial mg ÷ water mL. Units to draw = (dose in mcg ÷ (concentration × 1000)) × 100 on a U-100 syringe.
Worked examples
Verified reference figures for common vial sizes on a U-100 (insulin) syringe. These are unit-conversion results, not dose recommendations.
| Peptide in vial | Bacteriostatic water | Dose | Concentration | Volume | Units to draw |
|---|---|---|---|---|---|
| 5 mg | 2 mL | 250 mcg | 2.5 mg/mL | 0.10 mL | 10 units |
| 10 mg | 2 mL | 500 mcg | 5 mg/mL | 0.10 mL | 10 units |
| 5 mg | 1 mL | 250 mcg | 5 mg/mL | 0.05 mL | 5 units |
| 2 mg | 1 mL | 100 mcg | 2 mg/mL | 0.05 mL | 5 units |
Frequently asked questions
How do I calculate peptide reconstitution?
Divide the milligrams of peptide in the vial by the millilitres of bacteriostatic water to get the concentration in mg/mL. To find the units to draw on a U-100 syringe, divide your dose in mcg by the concentration in mcg/mL (concentration × 1000), then multiply by 100. For example, 5 mg in 2 mL gives 2.5 mg/mL; a 250 mcg dose is 0.10 mL, or 10 units.
How many units is one dose on an insulin syringe?
On a U-100 syringe, 100 units equals 1 mL. So 10 units is 0.10 mL and 50 units is 0.50 mL. The exact number of units for a given dose depends on the concentration you reconstituted to — use the calculator above to convert.
Does adding more water make the peptide weaker?
No. The total amount of peptide stays the same; adding more water only lowers the concentration. You then draw a larger volume (more units) to deliver the same amount of peptide. More water can make small amounts easier to measure accurately.
What water is used to reconstitute peptides?
Bacteriostatic water — sterile water containing 0.9% benzyl alcohol, which inhibits bacterial growth and allows multiple withdrawals over time. This is a laboratory handling note for research-use-only material, not human-use guidance.
Is this calculator medical advice?
No. It performs unit-conversion arithmetic only (mg, mL, mcg, syringe units). It is not medical, dosing or treatment advice. Research peptides are not approved for human or veterinary use.