Research peptides arrive as a white powder or a thin film in a glass vial, not as a liquid. That form is not a packaging choice but a chemical necessity. This guide explains what freeze-drying does and why it dictates how you store a peptide.
Lyophilisation is freeze-drying: freeze, then let the ice sublimate under vacuum so the water leaves without an intermediate step. Without water, hydrolysis cannot split the peptide bond, and that is what makes the powder stable enough to travel at ambient temperature.
What is lyophilisation?
Lyophilisation — freeze-drying — is a drying technique in which frozen water passes straight from solid to vapour without becoming liquid first. That transition is called sublimation and happens at low pressure. Because the liquid phase is skipped, the molecule is spared the mechanical and thermal load that ordinary evaporation brings.
- 1Freezing
The peptide solution is frozen solid inside the vial.
- 2Primary drying
Under vacuum the ice sublimates away. This is the longest step and removes most of the water.
- 3Secondary drying
Water still bound to the molecule is removed at a slightly higher temperature.
- 4Sealing
The vial is closed, labelled with the lot number and tied to the certificate of analysis for that batch.
Why peptides are freeze-dried
Because water is the enemy of the peptide bond. The reaction that splits such a bond — hydrolysis — needs water; without water that reaction simply cannot proceed. How the bond is built and why water in particular breaks it is in what is a peptide bond.
The practical consequence is large: a dry peptide is stable enough to travel at ambient temperature, while the same substance in solution has to stay refrigerated and keeps for far less time. So our shipments leave as powder; the details are in the shipping policy.
What you see in the vial — and what it means
A lyophilised cake is extremely light and can come loose, crumble or stick to the wall during transport. That says nothing about the amount of substance or about quality. It is the same mass, just distributed differently. At low fill weights the cake is sometimes barely more than a thin, translucent film on the bottom.
What does say something is the lot number on the label. It points to one specific certificate of analysis with the measured purity and molecular weight of that batch. Check it via verify a lot number, or browse all reports on certificates.
From powder back to solution
As soon as water is added, the chemistry above runs in reverse: the peptide becomes more vulnerable and its shelf life shortens. Reconstitution is typically done with bacteriostatic water, and the right ratio between amount of substance and volume is worked out with the reconstitution calculator.
The steps themselves — how to add the solvent and what not to do while doing it — are in how to reconstitute peptides. Why bacteriostatic water specifically is covered in bacteriostatic water. After reconstitution, keep it refrigerated and follow the instruction on the product page.
This information is general and educational in nature. Peptide Lab supplies research peptides for laboratory and research purposes only. Not for human or animal consumption, not a medicine and not medical advice.
Frequently asked questions about lyophilisation
What is lyophilisation?
Lyophilisation is freeze-drying: a solution is frozen first and then dried under vacuum, with the ice passing straight from solid to vapour (sublimation) without becoming liquid. What remains is a dry powder.
Why are peptides supplied freeze-dried?
Because water attacks the peptide bond. Hydrolysis — the reaction that splits the bond — needs water. Without water a peptide is therefore far more stable, including at ambient temperature, and much easier to ship and store.
The cake in my vial has shifted or looks thin. Is that a problem?
Usually not. A lyophilised cake is light and can come loose or stick to the wall during transport. That does not change the amount of substance in the vial. What matters is the lot number and its certificate of analysis.
How long does a lyophilised peptide keep?
Considerably longer than a peptide in solution. For long-term storage −20 °C is generally used. After reconstitution with bacteriostatic water it belongs refrigerated and has a limited shelf life; the per-product instruction is on the product page.
