Reconstitution done right, every time.
Improper reconstitution is the #1 cause of wasted peptides. This guide covers everything from storage temperatures to mixing techniques — so you preserve quality and get consistent results.
Preserving quality and stability
Proper storage is vital for maintaining the stability and integrity of peptides. Peptides in their lyophilised (freeze-dried) form are stable for transport as they are protected from UV light and remain stable in a freeze-dried state. However, refrigerating them as soon as possible upon arrival ensures proper storage and extends their longevity.
Storage temperature matters:
-20°C (freezer): Peptides remain stable for up to 48 months. Ideal for long-term storage.
2-8°C (refrigerator): Suitable for short-term storage and active use.
Room temperature: Acceptable briefly during transport, but not for extended periods.
Key principles:
Keep vials sealed until ready for use
Protect from direct light — UV degrades tryptophan and tyrosine residues
Let refrigerated or frozen vials reach room temperature before opening to prevent condensation
After reconstitution, aliquot into single-use volumes and store frozen
Avoid repeated freeze-thaw cycles
Storage duration guidelines
Different peptide types have similar storage profiles when handled correctly:
Lyophilised (freeze-dried) peptides:
Basic, acidic, neutral, hydrophobic, and hydrophilic peptides: Up to 48 months at -20°C
Peptides containing methionine or cysteine: May have shorter shelf life due to oxidation susceptibility
Reconstituted peptides:
Most peptides: 2-8 weeks at 2-8°C
Stability varies by peptide and solvent
Aliquot and freeze for longer storage
Avoid repeated freeze-thaw cycles
Degradation doesn't mean immediate loss of integrity. Peptides degrade gradually over time. As they break down, they lose structure and charge, leading to fragmentation and eventual loss of structural integrity. Proper storage dramatically slows this process.
Achieving optimal results
Peptides are typically supplied in lyophilised powder form, requiring reconstitution before use. For best results, allow both the peptide vial and the mixing solution to reach room temperature before mixing. This helps avoid issues like cloudiness that may occur when cold solutions are combined.
Step 1 — Equalise vial pressure:
Due to the drying process, some vials may have a vacuum while others have positive pressure. Insert a sterile needle half-filled with air into the vial's rubber stopper. The vial will either draw in or release air, stabilising the pressure. This prevents solution loss once liquid is added.
Step 2 — Choose the right solvent:
Bacteriostatic water is the most common choice for reconstitution. The benzyl alcohol preservative inhibits microbial growth and allows multiple withdrawals from a single vial.
Acetic acid solution is needed for certain peptides that require a lower pH to dissolve properly, especially hydrophobic peptides.
Create a stock solution at a higher concentration than necessary, allowing for later dilution with assay buffer.
Step 3 — Mix gently:
Gently swirl the vial until the peptide is fully dissolved. Avoid vigorous shaking — this can damage the peptide structure. If particles remain, sonication can help ensure complete dissolution.
Step 4 — Use appropriate volumes:
Use between 1 to 2.5 ml of solution for reconstitution unless specific studies confirm a higher volume is safe. Excessive dilution can compromise peptide integrity.
Common reconstitution issues
Cloudy solution
Usually caused by incomplete dissolution, pH mismatch, or too-high concentration. Gentle swirling at room temperature for a few minutes usually resolves this. If cloudiness persists, do not use — it may indicate aggregation.
Particles remaining
Some peptides take longer to dissolve, especially hydrophobic sequences. Try sonication for complete dissolution. Using dilute acetic acid instead of water can also help.
Bacterial contamination
Filter through a 0.2 um filter to prevent bacterial contamination. Always use bacteriostatic water rather than sterile water for multi-use vials.
Vial appears empty
5mg is a very small amount — roughly a few grains of fine salt. A thin film or barely visible powder at the bottom is normal. Weighing the vial is not a reliable verification method.
Excessive volume added
Adding too much solution can fragment and break down peptides. Stick to 1-2.5ml unless your protocol specifically requires more. Over-dilution compromises integrity.
Degraded after storage
Reconstituted peptides should be stored at 2-8°C and used within 2-8 weeks. For longer storage, aliquot into single-use volumes and freeze. Never repeatedly freeze-thaw.
to convert mg to mL, calculate syringe units, and determine concentrations for your reconstitution. No more mental math — get exact measurements for any vial size and dose.
Frequently asked questions
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