How the reconstitution math works
Every result comes from two numbers: the concentration of the solution and the amount you want in each aliquot.
| Step | Formula | Example (10 mg + 2 mL, 250 mcg) |
|---|---|---|
| Concentration | peptide (mcg) ÷ diluent (mL) | 10,000 ÷ 2 = 5,000 mcg/mL |
| Volume | target (mcg) ÷ concentration | 250 ÷ 5,000 = 0.05 mL |
| U-100 units | volume (mL) × 100 | 0.05 × 100 = 5 units |
| Aliquots per vial | peptide (mcg) ÷ target (mcg) | 10,000 ÷ 250 = 40 |
Reconstitution handling notes
- Let the lyophilized vial reach room temperature before adding diluent.
- Run the diluent slowly down the inside wall of the vial; don't spray it directly onto the powder.
- Swirl gently until clear. Avoid shaking, which can shear and foam peptide chains.
- Label the vial with the concentration and date, then refrigerate at 2–8 °C.
Choosing a diluent volume that makes the math round (for example 2 mL for a 10 mg vial gives 50 mcg per unit) reduces measurement error across a study.
Frequently asked questions
How do you calculate peptide concentration after reconstitution?
Divide the amount of peptide in the vial by the volume of diluent added. For example, 10 mg in 2 mL of bacteriostatic water gives 5 mg/mL, which is 5,000 mcg/mL.
How much volume holds a given amount of peptide?
Divide the target amount by the concentration. At 5,000 mcg/mL, 250 mcg is contained in 0.05 mL (50 µL), which is 5 graduations on a U-100 scale.
What is a U-100 graduation?
A U-100 scale is marked in 100 units per millilitre, so 1 unit equals 0.01 mL (10 µL). The calculator converts every result into mL, µL and units.
Does more diluent change the amount of peptide?
No. Adding more diluent only lowers the concentration, so a larger volume is needed for the same amount. The total peptide in the vial stays the same.
Which diluent is used for reconstitution?
Bacteriostatic water (0.9% benzyl alcohol) is the most common diluent for lyophilized research peptides. Some sequences call for sterile or acetic-acid water; check the handling notes for the compound and its certificate of analysis.
From lab to your door