Peptide storage

Most lyophilised research peptides are stable for years at -20 °C in a dry, light-protected environment. Once reconstituted into aqueous solution, stability drops sharply: many peptides lose activity within days at 4 °C and within weeks at -20 °C. The general rule for research workflows is: keep the lyophilised stock at -20 °C until needed, reconstitute only what's required for the immediate experiment, and aliquot any leftover into single-use volumes before refreezing. Repeated freeze-thaw cycles are a common cause of unexplained loss of activity.