Peptide Storage and Stability: A Research Reference

Lyophilized vs. Reconstituted Peptides

Research peptides arrive as freeze-dried powder. Freeze-drying removes water under vacuum, creating a stable solid. Dry peptides barely degrade-properly stored, they last 2-3 years or more.

Once you dissolve a peptide in water, stability drops fast. In solution, peptides degrade from hydrolysis, oxidation, and bacteria. Under refrigeration (2-8°C), you get about 4 weeks. At -20°C, maybe 6 months. Check the literature for your specific peptide.

Temperature Guidelines

Dry peptides: -20°C or colder for long-term. If you only need it for a few weeks, fridge (2-8°C) is okay. Avoid room temperature.

Dissolved peptides: fridge (2-8°C) for weekly use, -20°C for longer storage. Some peptides prefer -80°C if they're heat-sensitive. -20°C is standard.

Don't leave peptides at room temperature. Heat wrecks them-especially peptides with methionine, cysteine, or tryptophan.

Light Sensitivity

Light degrades peptides-UV and visible light both cause damage. Use amber vials or foil-wrapped containers. Especially important for peptides with aromatic amino acids (Phe, Tyr, Trp) or cysteines.

Freeze-Thaw Cycles

This is a killer. Every freeze-thaw wrecks reconstituted peptides. Ice crystals damage structure, and temperature swings speed degradation.

Solution: aliquot into single-use volumes before freezing. Use each aliquot once, then discard. The bulk stays frozen. More work upfront, much longer usable life.

BAC Water vs. Sterile Water

Use bacteriostatic water (BAC water)-sterile water with 0.9% benzyl alcohol preservative. The benzyl alcohol stops bacteria from growing in your peptide solution over weeks.

Plain sterile water has no preservative. It's okay for single-use, but multi-dose vials left in the fridge will get bacteria.

For standard multi-dose protocols: BAC water. Better stability, lower contamination risk.

Alternative: acetic acid (0.1-1%) for peptides that don't dissolve well. But BAC water is default.

--- For research use only. Not medical advice.