Lyophilization is freeze-drying — a controlled process that removes water from a peptide solution through sublimation under vacuum, leaving a dry, stable cake or thin film inside the vial. Done right, it produces a peptide product that’s stable at room temperature for shipping and long-term storage.
Why It’s Done
Peptides in aqueous solution are vulnerable to hydrolysis, oxidation, and bacterial contamination. Removing the water dramatically extends shelf life — from days or weeks (in solution) to months or years (lyophilized).
The Three-Phase Process
- Freezing. The aqueous peptide solution is frozen, typically at −40°C or below.
- Primary drying. Vacuum is applied. Frozen water sublimates directly to vapor, leaving the peptide solid.
- Secondary drying. Residual bound water is removed at slightly higher temperatures.
What a Good Lyophilized Cake Looks Like
- Solid cake or mat in the vial — not loose powder
- Uniform color (white to off-white for most peptides)
- No liquid pooling at the bottom
- No crusty residue on walls
Failure modes (collapsed cake, liquid pooling, discoloration) are described in Lyophilization and Vial Integrity.
The Reconstitution Step
Lyophilized peptides require reconstitution with a sterile solvent before use. The standard solvent is bacteriostatic water at 2 mL per 10 mg peptide, producing a 5 mg/mL solution. See the reconstitution calculator for protocol-specific math.
Research use only. Not for human consumption. Statements not evaluated by the US FDA.