How to store a reconstituted peptide vial

Before you mix it

Lyophilised powder is stable and forgiving. Reagent suppliers store it at −20°C or −80°C, but those are laboratory figures for multi-year shelf life. A sealed, unmixed vial kept cool, dry and out of direct light is the normal consumer situation.

After you mix it

• Refrigerate at 2–8°C. A normal fridge, not the freezer, and not the door.
• Keep it dark. GHK-Cu is light sensitive, so Glow and KLOW should go back in the box or a opaque container.
• Do not freeze a mixed vial. Freeze–thaw cycles are one of the documented ways peptides in solution degrade.
• Wipe the stopper with alcohol every single time you put a needle through it, not just the first time.

Why there is no expiry date on this site

The number you will see repeated across peptide sites is 28 days. We went looking for where it comes from and could not find a source that applies to this situation.

Reagent suppliers do publish stability data — for example six months at −80°C and one month at −20°C for peptides in solution. Those are freezer conditions in a laboratory. They say nothing about a vial in a kitchen fridge at 2–8°C, which is what actually happens.

So we left it out. The beyond-use date feature is switched off site-wide, and the calculator says so on every page rather than quietly filling in a plausible number. If your supplier gives you a figure, use theirs — they know what is in the vial and we do not.