What you need
- The peptide vial, at room temperature.
- A sterile diluent: bacteriostatic water for most peptides, or 0.6% acetic acid for peptides such as IGF-1 LR3.
- A sterile syringe to transfer the diluent. A U-100 1 mL insulin syringe is marked in units, which makes measuring easy.
- Alcohol swabs.
Step by step
- Let the peptide vial reach room temperature so condensation does not form inside.
- Remove the flip-off caps and wipe both rubber stoppers with an alcohol swab.
- Draw the planned volume of bacteriostatic water into a sterile syringe.
- Inject slowly down the inside wall of the vial, not directly onto the powder.
- Swirl gently until clear. Do not shake, since agitation can damage the peptide chain.
- Write the reconstitution date on the label and refrigerate at 2 to 8 °C.
Peptide reconstitution calculator
Enter the amount of peptide in the vial, the volume of diluent you plan to add and the amount you want per draw. The calculator gives the concentration and the volume to draw, in millilitres and in units on a U-100 syringe.
Reconstitution chart
| Vial | Water added | Concentration | Per 10 units (0.1 mL) |
|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 0.25 mg |
| 10 mg | 1 mL | 10 mg/mL | 1 mg |
| 10 mg | 2 mL | 5 mg/mL | 0.5 mg |
| 50 mg | 3 mL | 16.7 mg/mL | 1.67 mg |
On a U-100 insulin syringe, 10 units equals 0.1 mL. Adding less water gives a stronger solution and smaller draw volumes; adding more makes small amounts easier to measure accurately.
How much water to add
The peptide amount does not change with the water you add, only the concentration does. The formula is simple:
concentration (mg/mL) = peptide in vial (mg) ÷ water added (mL)
Choose a volume that makes the amounts you need easy to measure. For small amounts, more water spreads the peptide over more units on the syringe, which improves accuracy. Most 3 mL vials can hold up to about 3 mL of liquid.
Common mistakes
- Spraying water onto the powder. Run it down the glass instead.
- Shaking the vial. Swirl gently and give it time.
- Buying a 30 mL water vial for a single 5 mg peptide. Most of it will expire unused; a 3 mL vial covers one or two peptide vials.
- Not labelling the date. A reconstituted vial should be used within about 28 days.
