Everything You Need to Know About Reconstituting Peptides
A comprehensive guide to reconstituting, storing and handling lyophilised research peptides — including storage duration guidelines, step-by-step mixing technique, and solvent selection.
🧮 Free Peptide Dosing Calculator
Convert mg to mL, mcg to IU, and find the exact syringe mark for any vial size and dose.
Proper storage is vital for maintaining the stability and integrity of research peptides. Peptides in their lyophilised (freeze-dried) form are safe for transport as they are protected from UV light and remain stable in a freeze-dried state. Refrigerate as soon as possible upon arrival to ensure proper storage and extend longevity.
Peptides stored at -20°C in a freezer will remain stable for up to 48 months, making this ideal for long-term storage. When you receive peptides, store them immediately in your refrigerator (2–8°C) for short-term use or freezer (-20°C) for extended preservation.
Note: Peptides degrade gradually over time. Degradation doesn't mean reduced integrity initially, but as peptides break down they can lose structure and charge, leading to fragmentation and eventual loss of integrity.
Storage Duration Guidelines
Peptide Type
Lyophilised Storage
Reconstituted Storage
Basic Peptides
Up to 48 months at -20°C
2–8 weeks at 2–8°C
Acidic Peptides
Up to 48 months at -20°C
2–8 weeks at 2–8°C
Neutral Peptides
Up to 48 months at -20°C
2–8 weeks at 2–8°C
Hydrophobic Peptides
Up to 48 months at -20°C
2–8 weeks at 2–8°C
Hydrophilic Peptides
Up to 48 months at -20°C
2–8 weeks at 2–8°C
Peptide Reconstitution: Step-by-Step Guide
Peptides are supplied in lyophilised powder form and require reconstitution before use in research protocols. Follow these steps for best results.
1
Bring to room temperatureAllow both the peptide vial and your bacteriostatic water to reach room temperature before mixing. This prevents cloudiness that can occur when cold solutions are combined.
2
Equalise vial pressureInsert a sterile needle half-filled with air into the vial's rubber stopper. The vial will either draw in or release air, stabilising internal pressure. This prevents solution loss once liquid is added.
3
Add bacteriostatic water slowlyDraw up the required volume of bacteriostatic water in a syringe (use the calculator above to determine the right amount). Insert the syringe into the vial and inject the water slowly down the inside wall — not directly onto the peptide powder.
4
Gently swirl — do not shakeGently rotate and swirl the vial until the peptide is fully dissolved. Vigorous shaking can damage the peptide structure and should be avoided.
5
Refrigerate immediatelyOnce reconstituted, store at 2–8°C. Use within 2–8 weeks depending on the peptide type.
Tip: Use between 1ml and 2.5ml of bacteriostatic water for most research peptide vials. Adding too much can compromise peptide integrity. Use our free peptide calculator to find the exact volume for your target concentration.
Choosing the Right Solvent
Bacteriostatic water (0.9% benzyl alcohol) is the standard solvent for most lyophilised research peptides. The benzyl alcohol acts as a preservative, allowing multi-use from a single vial over several weeks.
Some peptides — particularly hydrophobic ones — may require a small amount of acetic acid for initial dissolution. A 50% aqueous acetic acid solution can be used as a stock solution at a higher concentration than needed, allowing later dilution with an assay buffer.
If the peptide won't fully dissolve
If particles remain after gentle swirling, sonication in a water bath for a few seconds can help ensure complete dissolution. Alternatively, filter through a 0.2µm sterile filter to remove any undissolved particulates and prevent bacterial contamination.
Frequently Asked Questions
How much bacteriostatic water should I add to a peptide vial? +
For most research peptides, use 1–2.5ml of bacteriostatic water. Adding too much dilutes the peptide unnecessarily and can compromise integrity. Use our peptide calculator to calculate the exact amount for your target concentration and syringe units.
How long do reconstituted peptides last? +
Once reconstituted with bacteriostatic water and stored at 2–8°C, most research peptides remain stable for 2–8 weeks. In lyophilised form stored at -20°C they can remain stable for up to 48 months.
Can I freeze reconstituted peptides? +
It is generally not recommended to refreeze reconstituted peptide solutions. Freeze-thaw cycles can damage peptide structure. Reconstitute only the amount needed for your experimental run and store the remainder lyophilised in a freezer.
Why is my reconstituted peptide cloudy? +
Cloudiness often occurs when cold bacteriostatic water is added to a vial that hasn't reached room temperature. Ensure both are at room temperature before mixing. If cloudiness persists, gentle sonication in a water bath for a few seconds can help.
What is bacteriostatic water and why use it? +
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol inhibits bacterial growth in the solution, making the vial suitable for multiple uses over several weeks. It is the standard reconstitution solvent for lyophilised research peptides.
For in vitro laboratory research use only. All Nova Biolabs products are sold strictly for research purposes. They are not intended for human consumption, medical use, or veterinary use. This guide is for research reference only and does not constitute medical advice.