How to reconstitute a lyophilized peptide
A generic walkthrough using bacteriostatic (BAC) water and a U-100 insulin syringe. For the exact math for a specific product, see its reference PDF.
What you'll need
- Your lyophilized peptide vial
- Bacteriostatic water (BAC water) — available as an ancillary
- U-100 insulin syringe, 29–31g · 5/16" or 1/2" needle
- Alcohol swab
The seven steps
1. Clean both vial stoppers
Swab the rubber stopper on both the peptide vial and the BAC water vial with an alcohol swab. Let dry for ~10 seconds.
2. Draw the BAC water
Pull the plunger back to your target volume (e.g. 2.0 mL for most 10 mg peptides). Insert the needle into the BAC water vial at a 45° angle, inject the air, then flip vertical and draw to your mark.
3. Inject the BAC water — slowly, along the glass wall
Insert into the peptide vial with the vial tilted. Direct the stream down the side of the glass, not directly onto the peptide cake. Peptides denature if foamed.
4. Let it dissolve on its own
Swirl gently — do not shake. The cake will re-solubilize on its own within 60 seconds. If flakes remain, swirl and wait another minute.
5. Label the vial
Write the reconstitution date on the cap or with a sharpie on the label. Refrigerate reconstituted peptide at 2–8°C.
6. Do the math
The concentration is vial_mg / volume_mL. A 10 mg vial reconstituted to 2 mL is 5 mg/mL, or 5,000 mcg/mL.
To dose 500 mcg from that vial: 500 / 5000 = 0.10 mL. On a U-100 insulin syringe, 0.10 mL = 10 units.
7. Store it right
- Reconstituted: refrigerate, use within 28 days typically.
- Lyophilized (unopened): fridge for long-term, freezer for >6 months.
- Do not freeze once reconstituted.