Work out exactly how far to draw the syringe after reconstituting a peptide vial — enter vial strength, how much bacteriostatic water you added, and your target research dose. Results show milliliters and insulin-syringe units.
Common research doses: 100 mcg = 0.1 mg | 250 mcg = 0.25 mg | 500 mcg = 0.5 mg | 1,000 mcg = 1 mg
Syringe fill visualization
The Reconstitution Math, Step by Step
- Concentration = vial strength ÷ water added. A 5 mg vial with 2 ml of bacteriostatic water gives 2.5 mg/ml
- Draw volume = target dose ÷ concentration. A 250 mcg (0.25 mg) dose at 2.5 mg/ml needs 0.1 ml
- Syringe units = ml × 100 on a standard U-100 insulin syringe. 0.1 ml = 10 units
Adding more water dilutes the solution — larger draw volumes per dose, which some researchers prefer for measurement precision at very small doses.
Reference: Common Vial / Water Combinations
| Vial | Water | Concentration | 250 mcg dose = |
|---|---|---|---|
| 5 mg | 1 ml | 5 mg/ml | 5 units |
| 5 mg | 2 ml | 2.5 mg/ml | 10 units |
| 10 mg | 2 ml | 5 mg/ml | 5 units |
| 10 mg | 3 ml | 3.33 mg/ml | 7.5 units |
| 30 mg | 3 ml | 10 mg/ml | 2.5 units |
FAQ
What are “units” on an insulin syringe?
U-100 insulin syringes mark 100 units per 1 ml. So 10 units = 0.1 ml, 25 units = 0.25 ml. The markings measure volume, not drug amount — how much peptide is in those units depends entirely on your reconstitution concentration.
Does the amount of bacteriostatic water change the dose?
No — the total peptide in the vial is fixed. Water only changes concentration: more water means a larger, easier-to-measure volume per dose; less water means a smaller volume.
How should reconstituted peptides be stored?
General laboratory practice is refrigeration at 2–8 °C, away from light, using bacteriostatic water (which contains 0.9% benzyl alcohol as a preservative). Stability varies by peptide — verify against the supplier’s documentation.
Is this medical advice?
No. This tool performs volume arithmetic only, for research and educational purposes. It does not recommend any dose, peptide, or use in humans. Consult a licensed physician for any medical decision.