Peptide reconstitution and storage guide
Every peptide we ship arrives as a lyophilised (freeze-dried) powder with a batch-specific Certificate of Analysis. This guide covers how to reconstitute that powder with bacteriostatic water, how to work out the concentration, and how to store the vial before and after reconstitution so the material stays intact. For laboratory research use only.
What you need
- The lyophilised peptide vial, still sealed and at room temperature
- Bacteriostatic water (USP grade, 0.9% benzyl alcohol) — sterile water only if the solution is used the same day
- A sterile syringe with a fine needle, alcohol swabs, and a clean bench surface
Bacteriostatic water, 10 ml is stocked alongside the peptides if you need it.
Step by step
- Let the vial reach room temperature. Reconstituting a vial straight from the freezer draws in condensation.
- Wipe both rubber stoppers — peptide vial and water vial — with an alcohol swab and let them dry.
- Draw the intended volume of bacteriostatic water into the syringe, usually 1–3 ml per vial.
- Angle the needle against the inside glass wall and let the water run down slowly. Never squirt it directly onto the powder cake.
- Leave the vial to dissolve on its own for a minute, then swirl gently. Do not shake — agitation shears peptide chains and causes foaming.
- The solution should be clear and free of particles. Cloudiness or visible flakes mean the material should not be used.
- Label the vial with the compound, the concentration and the reconstitution date, then refrigerate.
Working out the concentration
Concentration is simply the peptide mass divided by the water volume you added. A 10 mg vial reconstituted with 2 ml of bacteriostatic water gives 5 mg/ml, so 0.1 ml of solution contains 500 mcg. Adding less water gives a more concentrated solution and smaller measured volumes; adding more makes small quantities easier to measure accurately.
| Vial | Water added | Concentration | 0.1 ml contains |
|---|---|---|---|
| 5 mg | 1 ml | 5 mg/ml | 500 mcg |
| 10 mg | 2 ml | 5 mg/ml | 500 mcg |
| 10 mg | 1 ml | 10 mg/ml | 1 mg |
| 20 mg | 2 ml | 10 mg/ml | 1 mg |
Storage
Store lyophilised vials at –20 °C protected from light; they are stable for months in that state and tolerate ambient temperature during transit. Once reconstituted, keep the vial at 2–8 °C and use it within 30 days. Bacteriostatic water is what makes that 30-day window possible; a vial reconstituted with plain sterile water should be treated as single-day material.
- Keep vials upright, in the original box or an opaque container, away from the fridge door.
- Avoid repeated freeze–thaw cycles of a reconstituted solution; each cycle degrades the peptide.
- Never store solutions in direct light or above 25 °C, even briefly.
Common mistakes
- Shaking the vial to speed up dissolution — swirl instead and wait.
- Reconstituting the whole batch at once when only one vial is needed.
- Leaving a reconstituted vial unlabelled, so the concentration and date are lost.
- Freezing a solution made with bacteriostatic water instead of refrigerating it.
Each product page lists the exact storage terms and the batch Certificate of Analysis for that compound. Browse the peptides.