What Is Peptide Reconstitution?
Reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into an injectable solution using a sterile solvent. The most common solvent is bacteriostatic water (sterile water containing 0.9% benzyl alcohol as a preservative), which allows the reconstituted peptide to remain stable for multiple uses over several weeks.
The amount of solvent you add determines the concentration of the resulting solution, which in turn determines how much liquid you need to draw into the syringe for each dose.
How to Calculate Peptide Concentration
The formula is straightforward: divide the total peptide amount by the volume of water added.
Concentration (mg/mL) = Peptide Amount (mg) ÷ Water Volume (mL)
For example, dissolving a 5 mg vial in 2 mL of bacteriostatic water yields a concentration of 2.5 mg/mL. The same vial dissolved in 1 mL would yield 5 mg/mL — a more concentrated solution that requires less volume per dose.
Understanding Insulin Syringe Units
Most peptide injections use a standard U-100 insulin syringe, where 100 units equals 1 mL. This means:
- 1 unit = 0.01 mL
- 10 units = 0.1 mL
- 50 units = 0.5 mL
- 100 units = 1.0 mL
To calculate syringe units: divide your dose (in mg) by the concentration (in mg/mL), then multiply by 100. Or simply use the calculator above.
Common Reconstitution Examples
| Peptide | Vial | Water | Dose | Concentration | Units |
|---|---|---|---|---|---|
| BPC-157 | 5 mg | 2 mL | 250 mcg | 2.5 mg/mL | 10 |
| Semaglutide | 5 mg | 2 mL | 500 mcg | 2.5 mg/mL | 20 |
| Ipamorelin | 5 mg | 2.5 mL | 200 mcg | 2.0 mg/mL | 10 |
| TB-500 | 5 mg | 2 mL | 2,500 mcg | 2.5 mg/mL | 100 |
| CJC-1295 | 5 mg | 2.5 mL | 100 mcg | 2.0 mg/mL | 5 |
| GHK-Cu | 10 mg | 2 mL | 500 mcg | 5.0 mg/mL | 10 |
Tips for Accurate Reconstitution
- Inject water slowly along the inside wall of the vial — never squirt directly onto the powder, as this can damage the peptide.
- Swirl gently to dissolve. Do not shake, as agitation can denature the peptide and reduce potency.
- Store reconstituted peptides refrigerated at 2-8°C. Most remain stable for 3-4 weeks.
- Use bacteriostatic water rather than sterile water for multi-use vials. The preservative prevents bacterial growth.
- Use an alcohol swab to clean the vial stopper before each draw.