What Is Reconstitution?
Reconstitution is the process of adding a liquid (diluent) to a lyophilized (freeze-dried) peptide powder to create an injectable solution. Most peptides are shipped as a dry powder because they are far more stable in this form. The powder must be dissolved before use.
The most common diluent is bacteriostatic water (BAC water), which is sterile water containing 0.9% benzyl alcohol as a preservative. This preservative allows the reconstituted solution to be used over multiple doses, typically for up to 28 days when properly refrigerated. Some protocols may call for sterile water or normal saline — always use whatever your provider specifies.
Equipment You Will Need
- Lyophilized peptide vial
- Bacteriostatic water vial
- A syringe for reconstitution (typically a 1 mL or 3 mL syringe with a 25-27 gauge needle)
- Alcohol swabs
- Clean, flat work surface
Step-by-Step Reconstitution
1. Prepare Your Workspace
Wash your hands thoroughly. Work on a clean, flat surface. Gather all supplies before you begin. Avoid areas with drafts, fans, or high foot traffic that could introduce airborne contaminants.
2. Clean the Vial Stoppers
Wipe the rubber stopper of both the peptide vial and the BAC water vial with separate alcohol swabs. Let them air dry completely — about 10 seconds.
3. Draw the Bacteriostatic Water
Insert the reconstitution syringe needle through the BAC water vial stopper. Invert the vial and draw the amount of BAC water specified by your protocol. Common amounts are 1 mL or 2 mL, but this varies based on your peptide concentration needs. Remove air bubbles by tapping the syringe and gently pushing out any air.
4. Add Water to the Peptide Vial
Insert the needle through the peptide vial stopper. Aim the needle at the inside wall of the vial, not directly at the powder. This is critical — a direct stream of water hitting the peptide cake can damage fragile protein structures. Depress the plunger slowly, allowing the water to trickle gently down the glass wall.
5. Let It Dissolve — Do NOT Shake
Never shake a reconstituted peptide. Shaking introduces air bubbles, creates foam, and can denature (destroy) the peptide through mechanical stress. Instead, swirl the vial very gently in small circles, then set it down. Many peptides will dissolve on their own within 5-15 minutes. If the powder has not fully dissolved after gentle swirling, place the vial in the refrigerator and check again in 30 minutes. A properly reconstituted solution should be clear and free of visible particles.
6. Refrigerate Immediately
Once reconstituted, the peptide solution must be stored in the refrigerator at 36-46°F (2-8°C). Do not freeze a reconstituted peptide. Label the vial with the reconstitution date and the peptide name if it is not already labeled.
Dosing Math: How to Calculate Your Dose
Understanding dosing math is essential for drawing the correct amount from your reconstituted vial. The key formula is:
Dose in units = (Desired dose in mcg / Total mcg in vial) × Total units of water added
Example 1
You have a 5 mg (5,000 mcg) vial of a peptide. You add 2 mL of BAC water. You need a 250 mcg dose.
- Concentration = 5,000 mcg / 2 mL = 2,500 mcg per mL
- Using an insulin syringe: 1 mL = 100 units
- 250 mcg / 2,500 mcg per mL = 0.1 mL = 10 units on an insulin syringe
Example 2
You have a 10 mg (10,000 mcg) vial. You add 2 mL of BAC water. You need a 500 mcg dose.
- Concentration = 10,000 mcg / 2 mL = 5,000 mcg per mL
- 500 mcg / 5,000 mcg per mL = 0.1 mL = 10 units on an insulin syringe
Example 3
You have a 5 mg vial. You add 1 mL of BAC water. You need a 100 mcg dose.
- Concentration = 5,000 mcg / 1 mL = 5,000 mcg per mL
- 100 mcg / 5,000 mcg per mL = 0.02 mL = 2 units on an insulin syringe
When in doubt, add more BAC water — this makes it easier to measure small doses accurately. It does not change the total amount of peptide in the vial, only the concentration per unit of volume.
Signs of a Problem
- Cloudy solution: A properly reconstituted peptide should be clear. Cloudiness may indicate contamination or degradation.
- Particles or clumps: Visible particles that do not dissolve after gentle swirling and resting suggest the peptide may be damaged.
- Unusual color: Most reconstituted peptides are clear and colorless. Any yellow, brown, or other discoloration is a red flag.
If you observe any of these signs, do not use the solution. Contact your provider or the compounding facility.