Most research peptides, including everything in our catalog, ship as a lyophilized (freeze-dried) powder. Freeze-drying removes water so the peptide stays stable during shipping and storage. Before it can be used in an experiment it has to be reconstituted: dissolved in a suitable diluent at a known concentration. This guide walks through the process used in most labs.
1. Gather your materials
- The peptide vial, at room temperature (let a refrigerated vial sit for 10–15 minutes so condensation doesn’t form inside).
- A diluent. For multi-use vials, bacteriostatic water (sterile water with 0.9% benzyl alcohol) is the usual choice. See bacteriostatic vs sterile water for when each fits.
- Sterile pipettes or a calibrated syringe for measuring liquid, alcohol swabs, gloves, and a clean work surface.
- The batch’s Certificate of Analysis. It confirms the actual peptide content (see how to read a COA).
2. Decide on your concentration
Concentration is simply the amount of peptide divided by the volume of diluent. A 10mg vial dissolved in 2mL gives 5mg/mL, which is the same as 5,000µg/mL or 5µg/µL. Choose a volume that makes later measurements easy. Round numbers like 1mL, 2mL or 2.5mL keep the math simple.
Our free Reconstitution Calculator does this instantly: enter the vial size and diluent volume to get the concentration, then enter a target amount to see exactly how many microlitres to measure.
3. Add the diluent slowly
- Wipe the vial’s rubber stopper and the diluent’s stopper with an alcohol swab and let them dry.
- Draw up the measured volume of diluent.
- Insert the needle and aim the stream down the inside wall of the vial, not directly onto the powder. Add it slowly.
- Don’t shake. Gently swirl or roll the vial between your fingers until the powder dissolves. Most peptides dissolve within a minute or two; some larger or more hydrophobic molecules take longer.
The solution should be clear. Persistent cloudiness or visible particles can mean the peptide needs a different solvent, or that the material has degraded. Check the COA and contact the supplier.
4. Label and store it
Label the vial with the compound, concentration, lot number and date reconstituted. Reconstituted peptides are far less stable than dry powder, so keep them refrigerated at 2–8°C and protected from light. Our storage and stability guide covers how long each form typically lasts, and the Lab Inventory Tracker keeps discard-by dates for you.
Common mistakes to avoid
- Shaking the vial. Agitation can cause foaming and aggregation of some peptides.
- Spraying diluent onto the powder. Run it down the vial wall instead.
- Not recording the concentration. Without it, every later measurement is guesswork.
- Leaving vials at room temperature. Return reconstituted vials to the fridge promptly.
Frequently asked questions
Can I reconstitute with tap or distilled water?
No. Use a sterile diluent. Non-sterile water can introduce contaminants and microbes that degrade the peptide and spoil results.
Why does my vial look almost empty?
A few milligrams of lyophilized peptide is a very small amount. It often appears as a thin film or small “puck” at the bottom of the vial. That’s normal.
All Ocean Peptide Labs products are for laboratory research use only and are not for human or animal consumption.
Keep reading
- Peptide Storage and Stability: Lyophilized vs Reconstituted
- Bacteriostatic Water vs Sterile Water for Peptide Reconstitution
- How to Read a Peptide Certificate of Analysis (COA): HPLC, Mass Spec and Purity
Free tools: Compound Library · Reconstitution Calculator · Lab Inventory Tracker · Research Kit Builder