What is reconstitution?
Reconstitution is the process of dissolving freeze-dried (lyophilized) peptide powder with bacteriostatic water to create an injectable solution. Your medication ships as a dry powder because it's more stable and has a longer shelf life in this form. Once mixed, the solution is ready for dosing.
- You only reconstitute once per vial - after mixing, draw multiple doses from the same vial
- The amount of water you add determines your concentration - this affects how many units you draw per dose
- Reconstituted medication must be refrigerated and used within 28 days
- Never shake the vial - shaking denatures (destroys) the peptide
What you'll need
- Lyophilized peptide vial (check mg on label)
- Bacteriostatic water vial (BAC water)
- 1 mL insulin syringe (100 unit)
- Alcohol swabs (70% isopropyl)
- Clean, flat workspace with good lighting
- Pen/marker to label the vial after mixing
Reconstitution steps
Follow these 8 steps exactly. The entire process takes about 10-15 minutes, including dissolving time.
Wash your hands
Wash thoroughly with soap and warm water for at least 20 seconds. Dry with a clean paper towel (not a hand towel - those harbor bacteria). Set up your workspace on a clean, flat surface.
Check your vials
Inspect the peptide vial - you should see a white or off-white cake or powder at the bottom. If the powder looks discolored (yellow, brown) or the vial is cracked, do not use it. Check the BAC water vial - the liquid should be clear and colorless.
Sterilize both vial tops
Use a fresh alcohol swab to wipe the rubber stopper on the peptide vial. Use a separate swab for the BAC water vial. Wipe firmly in one direction - don't just dab. Let the alcohol air dry completely (10-15 seconds). Do not blow on the stoppers.
Draw bacteriostatic water into the syringe
With a new insulin syringe, push the needle through the center of the BAC water vial's rubber stopper. Invert the vial (flip it upside down) so the liquid covers the needle tip. Slowly pull the plunger to draw the amount of water specified on your dosing card.
How much water to add: Check the reference table below. Common amounts are 1 mL (100 units) or 2 mL (200 units). More water = lower concentration = more units per dose. Less water = higher concentration = fewer units per dose.
Add water to the peptide vial - slowly
Insert the needle into the peptide vial through the stopper. Aim the needle at the inside wall of the vial, NOT directly at the powder. Slowly depress the plunger to let the water trickle down the glass wall. The water should drizzle onto the powder, not blast into it.
Let it dissolve - do NOT shake
Remove the syringe. Set the vial on your workspace and wait. The powder will begin dissolving on its own within 2-5 minutes. Never shake the vial. If needed, you can gently:
- Roll the vial between your palms (not vigorously)
- Tilt it slowly side to side
- Swirl gently in small circles
Most peptides dissolve completely in 5-10 minutes. The solution should be completely clear and colorless - like water.
Label the vial
Write the following on the vial or a piece of tape:
- Date reconstituted (e.g., "Mixed 7/15/2026")
- Concentration (e.g., "5 mg / 2 mL = 2.5 mg/mL")
- Expiration (28 days from mixing date)
Refrigerate immediately
Place the reconstituted vial upright in your refrigerator at 36-46°F (2-8°C). The center shelf is ideal - avoid the door (temperature fluctuates) and freezer. The vial is now ready for dosing.
BAC water ratios & concentration table
The amount of bacteriostatic water you add determines the concentration of your solution. Higher concentration = fewer units per dose. Your dosing card specifies the exact amount to use.
| Peptide in Vial | BAC Water Added | Concentration | 0.25 mg dose | 0.5 mg dose | 1.0 mg dose |
|---|---|---|---|---|---|
| 5 mg | 1 mL | 5.0 mg/mL | 5 units | 10 units | 20 units |
| 5 mg | 2 mL | 2.5 mg/mL | 10 units | 20 units | 40 units |
| 10 mg | 1 mL | 10.0 mg/mL | 2.5 units | 5 units | 10 units |
| 10 mg | 2 mL | 5.0 mg/mL | 5 units | 10 units | 20 units |
| 10 mg | 3 mL | 3.33 mg/mL | 7.5 units | 15 units | 30 units |
| 15 mg | 2 mL | 7.5 mg/mL | 3.3 units | 6.7 units | 13.3 units |
| 15 mg | 3 mL | 5.0 mg/mL | 5 units | 10 units | 20 units |
Highlighted rows show the most common configurations. Units = marks on a 100-unit insulin syringe. 1 mL = 100 units. Your dosing card specifies the exact configuration for your prescription.
Common mistakes & how to avoid them
Related guides
Syringe Reading Guide
How to read insulin syringe markings and draw accurate doses.
Learn more →Injection Sites Guide
Where to inject and how to rotate sites properly.
Learn more →Injection Instructions
Step-by-step reconstitution and injection guide for your medication.
Learn more →Need help with your medication?
Your care team is available 7 days a week for reconstitution, dosing, and injection questions.