Peptide Reconstitution Calculator
Enter your vial size and desired dose to instantly calculate the exact volume to inject — in both mL and insulin syringe units.
How to reconstitute a peptide vial
Gather supplies
Peptide vial, bacteriostatic water (BAC water), insulin syringe, and alcohol swabs. Do not use regular sterile water.
Clean both stoppers
Swab the rubber stoppers on both vials with alcohol. Let air-dry for 30 seconds before inserting a needle.
Draw BAC water
Use the calculator below to find the right volume. 2 mL is a common starting point for a 5 mg vial.
Inject down the side
Angle the needle so liquid runs down the vial wall, not directly onto the powder. Never shake — swirl only.
Swirl until dissolved
Roll between your palms for 30–60 seconds. The solution should be completely clear. Discard if cloudy.
Refrigerate
Store at 2–8°C. Most peptides are stable for 30–60 days refrigerated. Never freeze a reconstituted vial.
Calculate your dose
Check your vial label — typically 2 mg, 5 mg, or 10 mg.
More BAC water = lower concentration = larger injection volume per dose.
Check the peptide profile page for typical dose ranges.
Results
Volume indicator
Quick-reference concentrations
Resulting concentration (mcg/mL) for common vial sizes and BAC water volumes. Your current selection is highlighted.
| Peptide / BAC Water | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 5 mg | 5000 mcg/mL | 2500 mcg/mL | 1667 mcg/mL |
| 10 mg | 10000 mcg/mL | 5000 mcg/mL | 3333 mcg/mL |
| 20 mg | 20000 mcg/mL | 10000 mcg/mL | 6667 mcg/mL |
| 30 mg | 30000 mcg/mL | 15000 mcg/mL | 10000 mcg/mL |
| 40 mg | 40000 mcg/mL | 20000 mcg/mL | 13333 mcg/mL |
| 50 mg | 50000 mcg/mL | 25000 mcg/mL | 16667 mcg/mL |
| 100 mg | 100000 mcg/mL | 50000 mcg/mL | 33333 mcg/mL |
Common questions
Why does the syringe unit (IU) matter?
Insulin syringes measure in U-100 units — 100 units = 1 mL. Converting your dose to units prevents measurement errors, since the syringe markings correspond directly to units, not mL.
What if my dose is less than 10 units on the syringe?
Very small volumes are hard to measure accurately. Consider adding more BAC water to reduce the concentration, which gives you a larger, easier-to-measure volume per dose. Use the calculator to find the right balance.
Can I use sterile water instead of BAC water?
Only if you plan to use the entire vial in a single session. BAC water contains 0.9% benzyl alcohol as a preservative, which is what keeps the reconstituted peptide stable for weeks. Without it, the vial must be used within 24 hours.
Why do I add BAC water to the peptide vial (not the other way)?
Adding liquid to the lyophilised powder — not the reverse — prevents the powder from sticking to the needle or becoming unevenly distributed. The direction matters for consistent concentration.
Storage temperature
Refrigerate at 2–8°C (36–46°F). Never freeze a reconstituted vial — freezing degrades the peptide.
Shelf life
Most peptides remain stable for 30–60 days once reconstituted with BAC water when stored correctly.
Use BAC water only
Bacteriostatic water contains 0.9% benzyl alcohol as a preservative. Regular sterile water has no preservative and requires single-use.
Research use only
This calculator is provided for informational and research purposes only. Peptides discussed on Peptipedia are not approved for human therapeutic use unless otherwise noted. Always consult a qualified healthcare professional before administration.