Lyophilisation

Lyophilisation (freeze-drying) is a dehydration process in which a peptide solution is first frozen at very low temperature and then subjected to a high-vacuum environment that causes the ice to sublimate directly from solid to vapour — bypassing the liquid phase — leaving behind a dry, porous solid cake. The resulting lyophilised powder retains the three-dimensional structure and biological activity of the peptide while being stable at ambient or refrigerated temperatures far longer than a liquid formulation.

Why it matters in peptide research

Peptides in aqueous solution are vulnerable to hydrolysis, oxidation, deamidation, and aggregation — degradation pathways that are all dramatically slowed or halted in the water-free lyophilised state. For research peptides with short solution half-lives, such as growth hormone secretagogues, GHRH analogues, and neuropeptides, lyophilisation is the standard preservation method because it extends shelf life from days (in solution) to months or years (as lyophilised powder) when stored correctly.

The lyophilisation process itself matters for product quality. A well-lyophilised cake should be white, uniform, and free of visible cracks or collapse — signs that the primary and secondary drying phases were properly controlled. A collapsed or glassy cake indicates that the sample temperature exceeded the product's collapse temperature during primary drying, which can compromise reconstitution behaviour and biological activity. Reputable peptide suppliers use validated lyophilisation cycles with controlled freeze rates and carefully staged shelf temperature ramps.

Once lyophilised peptide is reconstituted with bacteriostatic water, peptide solution stability again becomes the limiting factor. Reconstituted peptides should typically be refrigerated at 2–8°C and used within 28–30 days; multiple freeze-thaw cycles after reconstitution should be avoided. The reconstitution volume used determines the resulting concentration, which must be calculated accurately to ensure correct dosing — the reconstitution calculator on this site simplifies this step.

Peptides / stacks that act on this

• Reconstitution calculator — use to calculate the correct diluent volume for your lyophilised peptide vial given a target concentration

Common misconceptions

Lyophilised peptides are not indestructible. UV exposure, repeated temperature cycling above the storage temperature, and extended storage of reconstituted solution all degrade the product. "Freeze-dried" on a label indicates a preservation method, not a guarantee of indefinite stability — always check the expiry date and maintain cold-chain conditions from receipt.