Lab notes · Lab Practice
Storing and Handling Lyophilized Peptides: Best Practices
Freeze-dried peptides are stable, but only if they are stored and handled correctly. A practical field guide to temperature, moisture, light, and reconstitution.
The stable form is the freeze-dried form
Most research-grade peptides arrive lyophilized, meaning freeze-dried into a dry powder. That is not an accident: the lyophilized form is the most stable physical form a peptide can take, and it is how quality vendors ship. Before you do anything else, verify the vial is intact, the seal is unbroken, and the lot number on the label matches the Certificate of Analysis in the package. Five minutes of checking now saves a wasted experiment later.
Temperature: cold and stable
For long-term storage, keep sealed lyophilized powder at minus 20 degrees Celsius, where it typically remains stable for one to three years, or at minus 80 degrees for ultra-long-term storage of five years or more. Refrigeration at 2 to 8 degrees is only a short-term option, good for about three to six months. What damages peptides more than any single temperature is cycling: repeated warming and cooling accelerates degradation, so choose one stable environment and leave the vial there. Brief room-temperature exposure during shipping is generally tolerated, which is why the cold chain does not have to be dramatized, just respected.
Moisture and light are the real enemies
Lyophilized peptide powder is hygroscopic, meaning it pulls water out of the air the moment it can. Water in the vial is degradation in progress. Before opening, allow the vial to warm to room temperature, ideally inside a desiccator, so the powder does not suck moisture from the air. Keep desiccant in the storage container, protect vials from light, and be especially careful with oxidation-sensitive residues such as cysteine and methionine, which want both amber vials and minimal air exposure.
Reconstitution without drama
When it is time to reconstitute, collect the powder at the bottom of the vial first with a brief spin in a centrifuge. Add the solvent slowly, using the sterile solvent appropriate to the application, and swirl gently rather than vortexing hard. Reconstitute only what you need. After reconstitution, storage is a different game: keep working solutions at 2 to 8 degrees for days to a few weeks, or aliquot into single-use volumes and freeze for longer, always avoiding repeated freeze-thaw cycles. Note that a few peptides, NAD+ among them, should not be frozen after reconstitution at all, so check the sequence before you decide.
When in doubt, ask
Handling peptides well is a learned skill, and every peptide is slightly different. Our team answers handling questions every day, from first-time buyers to experienced labs, and we publish the full details in our lab notes. If a specific peptide in your order has special storage requirements, that is exactly the kind of thing we want you to know before you open the vial.
Sources
This note draws on published research and industry references. The direct links are listed so you can verify every claim yourself.
Knowledge, backed by product.
Every Amino Arsenal order ships with the same documentation standard we write about here.