Reconstitution Calculator
Laboratory math for reconstituting lyophilized peptides: enter the amount, vial size and diluent to see the volume to measure on a U-100 syringe.
The quantity of peptide you need per measurement. For mcg, divide by 1,000 (250 mcg = 0.25 mg).
Use the tested amount from the COA if you have it — vials are rarely exactly what the label says.
Changes the concentration, not the amount measured.
Draw to
Shown on a 0.3 mL (30-unit) U-100 syringe
- Concentration
- 2.50 mg/mL
- Measurements per vial
- 20
1. Concentration = 5 mg ÷ 2 mL
2. Volume = 0.25 mg ÷ concentration
3. Units = volume (mL) × 100 (U-100 syringe)
Common reconstitution amounts
Units to draw on a U-100 syringe.
| Vial + water | 0.25 mg | 0.5 mg | 1 mg | 2 mg | 2.5 mg |
|---|---|---|---|---|---|
| 5 mg + 1 mL | 5.0 | 10.0 | 20.0 | 40.0 | 50.0 |
| 5 mg + 2 mL | 10.0 | 20.0 | 40.0 | 80.0 | 100.0 |
| 10 mg + 2 mL | 5.0 | 10.0 | 20.0 | 40.0 | 50.0 |
| 10 mg + 3 mL | 7.5 | 15.0 | 30.0 | 60.0 | 75.0 |
How the reconstitution math works
Lyophilized (freeze-dried) peptides arrive as a powder with a known mass, such as 5 mg. Adding a measured volume of liquid turns that mass into a solution with a predictable concentration. Three steps give you any measurement:
- Concentration = peptide in the vial (mg) ÷ liquid added (mL). A 5 mg vial with 2 mL added is 2.5 mg/mL.
- Volume = amount you need (mg) ÷ concentration (mg/mL). Measuring 0.25 mg from a 2.5 mg/mL solution takes 0.1 mL.
- U-100 units = volume (mL) × 100. A U-100 syringe holds 100 units per mL, so 0.1 mL is 10 units.
Worked examples
- 10 mg vial + 2 mL → 5 mg/mL. Measuring 0.5 mg = 0.1 mL = 10 units.
- 5 mg vial + 1 mL → 5 mg/mL. Measuring 1 mg = 0.2 mL = 20 units.
- 10 mg vial + 3 mL → 3.33 mg/mL. Measuring 1 mg = 0.3 mL = 30 units.
Frequently asked questions
Does adding more water change the amount of peptide?
No. More liquid lowers the concentration, so you measure a larger volume for the same amount. The total mass in the vial stays the same.
What if my vial doesn't contain exactly what the label says?
It often doesn't. Third-party lab reports (COAs) list the measured content. Use that number as the vial size for more accurate math — you can find reports on our Lab Report page or with the batch number lookup.
Why keep measurements between about 10 and 50 units?
Very small volumes are hard to measure precisely on a syringe scale, and very large ones may exceed a smaller syringe. Adjusting the liquid volume moves the measurement into an easy-to-read range.
Can I convert micrograms (mcg)?
Yes — divide by 1,000. 250 mcg is 0.25 mg.
For laboratory research and educational purposes only. This tool performs unit conversions; it is not dosing guidance, medical advice or an endorsement of human or animal use.