How Research Peptides Are Stored and Handled in the Lab

How a peptide is stored affects whether your experiment measures the peptide or its breakdown products. This guide covers the laboratory basics, and what to ask suppliers about shipping.

Why peptides degrade

Peptides break down in several ways:

• Hydrolysis — water cleaves peptide bonds, especially at aspartate residues
• Oxidation — methionine, cysteine and tryptophan are particularly sensitive
• Deamidation — asparagine and glutamine residues convert to acidic forms
• Aggregation — some sequences clump together, especially at high concentration

Heat, moisture, light and repeated freeze–thaw cycles all speed these processes up.

Lyophilised (freeze-dried) powder

Most research peptides are supplied lyophilised, which is the most stable form.

• Long-term: store sealed vials at −20 °C or below, protected from light
• Short-term: many lyophilised peptides tolerate refrigeration (2–8 °C) or brief periods at room temperature, but check the supplier's data
• Moisture: let cold vials warm to room temperature before opening, so condensation doesn't form inside. Many peptides are hygroscopic (they absorb water from the air)

Peptides in solution

Once dissolved, peptides are much less stable:

• Aliquot into single-use portions to avoid repeated freeze–thaw cycles
• Choose the right solvent. Some peptides need a slightly acidic solvent, such as acetic acid water, to dissolve. Where a container will be accessed more than once, labs may use a preserved diluent such as bacteriostatic water
• Use sterile technique to prevent microbial growth, which also degrades peptides
• Record the date and keep to the stability windows established for your assay

Sensitive compounds

Some catalogue items need extra care: thiol-containing compounds such as glutathione oxidise readily; long lipidated peptides can aggregate; and copper complexes such as GHK-Cu can be sensitive to pH.

What to ask suppliers about shipping

• Is the product shipped lyophilised, and in a sealed, desiccated vial?
• Is cold-chain packaging used in warm weather?
• Is the CoA's test date recent relative to the shipping date?
• What storage conditions does the supplier recommend for this specific product?

Summary

Keep lyophilised peptides cold, dry and dark. Aliquot solutions to avoid freeze–thaw cycles, and choose solvents that suit the sequence. Ask suppliers how they ship. For laboratory research only — not for human or veterinary use.