Lyophilised (freeze-dried)

Lyophilisation, also called freeze-drying, is the standard preservation method for peptides intended for long-term storage and shipping. The process involves freezing the peptide solution rapidly to lock the molecular structure in place, then removing the water by sublimation under high vacuum at low temperature. The result is a fluffy white to off-white solid - the lyophilizate - that contains the original peptide molecules in a dry, glassy state without thermal degradation. Lyophilised peptides offer several practical advantages for research supply: dramatically extended shelf life (years at -20°C versus days to weeks for aqueous solutions); resistance to microbial contamination (water is required for microbial growth); preserved chemical integrity (no hydrolysis, oxidation, or deamidation in the dry state); and reduced shipping cost and complexity (no cold chain required for transit). The lyophilizate is typically reconstituted at the lab bench just before use by adding sterile water, bacteriostatic water, or a specific buffer to the vial, with gentle inversion to dissolve. The mass shown on the COA refers to the net peptide content, not the total lyophilizate weight (which may include counter-ions, residual buffer salts, or excipients). For peptides supplied with bulking agents like mannitol, the COA should specify both the peptide content and the total fill weight. Storage of the unreconstituted lyophilised vial at -20°C in a sealed container is the gold standard; some labs use -80°C for extra long-term storage. Once reconstituted, the solution should be aliquoted and stored according to peptide-specific guidance to avoid freeze-thaw degradation.