Guide

Peptide Storage: Before and After Reconstitution

Peptides are chains of amino acidsAmino acidThe chemical building block of peptides and proteins. Peptides are short chains of amino acids linked together by peptide bonds.See glossary → held together by bonds that heat, light, agitation, and time all attack. Storage is not an afterthought — a properly stored vial and a badly stored one can contain very different amounts of intact peptide by the end of a research cycle. The rules split cleanly into before and after reconstitutionReconstitutionThe process of mixing a freeze-dried (lyophilized) peptide powder with bacteriostatic water to create a solution of known concentration.See glossary →.

Before reconstitution: the dry powder

LyophilizedLyophilizedFreeze-dried. Peptides are shipped as a lyophilized powder ('puck') because the dry form is far more stable than a solution. It must be reconstituted before use in research.See glossary → peptide is the stable form — that's the whole point of freeze-drying. Referenced storage windows:

Practical notes:

• Keep vials in their box or another dark container — several peptides degrade under light.
• Avoid repeated freeze–thaw of the dry powder; condensation introduces moisture, and moisture is the enemy of a lyophilized cake.
• If a freezer-stored vial comes out, let it reach fridge or room temperature before piercing the stopper, so humid air doesn't condense inside.

After reconstitution: the clock starts

Once bacteriostatic waterBAC water (bacteriostatic water)Sterile water containing 0.9% benzyl alcohol, which suppresses bacterial growth. It is the standard diluent used to reconstitute lyophilized peptides for multi-dose research vials.See glossary → goes in, two degradation processes begin: chemical breakdown of the peptide in solution, and — much more slowly, thanks to the benzyl alcohol — potential microbial growth. From this point:

• Always refrigerated. 2–8°C, no exceptions in the reference literature.
• Never frozen. Ice crystals shear peptide molecules apart.
• Dark. Back of the fridge, in the box.
• Dated. Write the mixing date and concentration on the label the day you mix.

Compound-specific windows

Stability after reconstitution varies more than most researchers expect:

Each peptide's profile page carries its specific storage line — check it when planning how many vials to reconstitute at once. Reconstituted with plain sterile water instead of BAC water? The referenced window collapses to 24–72 hours.

Travel and transit

• Short trips (a day or two): an insulated pouch with a cold pack keeps reconstituted vials in range. Don't let vials sit in direct contact with ice — freezing is worse than a few hours cool.
• Flights: dry powder travels well at cabin temperature for days; reconstituted vials are the fragile ones.
• Receiving a shipment: lyophilized peptide arriving at summer courier temperatures is generally referenced as fine — refrigerate on arrival.

Signs a vial has gone wrong

• Cloudiness or floating particles after the solution had been clear
• Discoloration (except GHK-Cu, which is naturally blue)
• A powder puck that turned gummy or discolored before mixing

Document and discard. No dose is worth measuring from a compromised vial — and if the vial was recently purchased, a photo plus the lot number is exactly what a vendor's COACOA (Certificate of Analysis)A lab document reporting what a specific batch actually contains — typically purity by HPLC and identity by mass spectrometry. Reputable research vendors publish batch-specific COAs.See glossary →-backed support process needs.