Peptide Storage Guidelines

Why storage matters

Lyophilized peptides are stable compounds, but improper handling degrades them quickly. Temperature cycling, moisture, and light exposure all shorten usable shelf life and introduce variability into research results.

Lyophilized (powder) storage

• Store sealed vials at -20°C for long-term storage. At this temperature most research peptides remain stable for 24 months or longer.
• Short-term storage at 4°C is acceptable for up to 30 days.
• Keep vials in the original light-blocking packaging. UV exposure accelerates oxidation of methionine, cysteine, and tryptophan residues.
• Allow vials to reach room temperature before opening. Opening a cold vial pulls in ambient moisture, which condenses on the powder.

Reconstituted storage

• Once reconstituted with bacteriostatic water, store at 2-8°C and use within 30 days.
• Do not freeze reconstituted peptide in a standard freezer. Ice crystal formation shears the peptide chain.
• If longer storage is unavoidable, aliquot into single-use volumes and store at -80°C to avoid freeze-thaw cycling.

Freeze-thaw cycles

Each freeze-thaw cycle measurably reduces potency. Aliquot immediately after reconstitution so that each vial is thawed exactly once.

Signs of degradation

Cloudiness, visible particulates, a yellow tint, or an off odour in a reconstituted solution all indicate the material should not be used for quantitative work.