Peptide reconstitution: the arithmetic, step by step
How concentration works when a freeze-dried peptide is mixed with water, how U-100 syringe units convert to millilitres, and a calculator that does the sums.
Most research peptides ship as a freeze-dried powder. Adding a known volume of liquid turns it into a solution of known concentration. From there, every other number follows.
1. Concentration
Concentration is the amount of peptide divided by the volume of liquid. A vial with 5 mg of peptide mixed with 2 mL of liquid has a concentration of 2.5 mg/mL, which is 2,500 mcg/mL (1 mg = 1,000 mcg).
2. Syringe units
A U-100 insulin syringe is marked so that 100 units = 1 mL. One unit is therefore 0.01 mL. The unit marks measure volume, not peptide.
3. Putting it together
At 2,500 mcg/mL, each unit (0.01 mL) holds 25 mcg. Ten units hold 250 mcg. Change the volume of liquid and every one of these numbers changes with it, which is why writing down the volume used matters.
| Liquid added | Concentration | Per unit |
|---|---|---|
| 1 mL | 5,000 mcg/mL | 50 mcg |
| 2 mL | 2,500 mcg/mL | 25 mcg |
| 3 mL | 1,667 mcg/mL | 16.7 mcg |
Use the calculator below to run the same sums for any vial. It assumes the vial holds exactly what the label says, which is one more reason to check the certificate of analysis.
Reconstitution calculator
Arithmetic only. It assumes the vial holds exactly what the label says.
- Concentration
- 2,500 mcg/mL
- Per U-100 unit
- 25 mcg
- Volume for your amount
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Related peptides
Research and education only. Not medical advice. Many peptides on this site are not approved by the FDA for human use. Doses shown are the ones used in published studies and are not a recommendation. Talk to a licensed clinician before using any of them. Read the full disclaimer.