Reference

Storage and handling for lyophilized peptides

Most research peptides ship as a lyophilized (freeze-dried) powder because a dry peptide is far more stable than one in solution. These are the general laboratory practices that keep it that way. Always follow your own lab's procedures and the safety data sheet.

Storing the dry powder

• Cold: keep sealed vials at −20 °C or below for storage longer than a few weeks. Short periods at room temperature, such as transit, are generally tolerated by the dry powder.
• Dark: protect vials from direct light, especially peptides containing tryptophan.
• Dry: lyophilized peptides absorb moisture from the air. Let a cold vial reach room temperature in a desiccator before opening it, so condensation doesn't form on the powder, then reseal it promptly.

Residues that need extra care

Some amino acids make a peptide more sensitive. Cysteine, methionine and tryptophan oxidize in air; asparagine and glutamine can deamidate in solution. For these sequences, minimize time open to air, consider purging the vial with nitrogen or argon before resealing, and prepare solutions shortly before use.

Compounds in our catalog that contain one of these residues: TB-500, Tesamorelin, CJC-1295 (no DAC), MOTS-c, Semax, PT-141, Melanotan II, Thymosin α1, Oxytocin, DSIP, Sermorelin, GHRP-2, GHRP-6, Kisspeptin-10, Melanotan I, VIP, Snap-8, Glutathione.

Peptides in solution

• Solutions are much less stable than the dry powder. Prepare only what an experiment needs.
• Divide a stock solution into single-use aliquots and freeze them, so each aliquot is thawed once. Repeated freezing and thawing degrades peptides.
• Sterile, slightly acidic buffers (around pH 5 to 6) suit most peptides better than neutral or basic ones.

Choosing a solvent

Solubility depends on the sequence. A common approach is to test a small portion first:

• Net positive charge (rich in lysine, arginine or histidine): try sterile water, then dilute acetic acid.
• Net negative charge (rich in aspartate or glutamate): try sterile water, then a dilute ammonium bicarbonate solution.
• Mostly hydrophobic: dissolve in a minimal amount of an organic solvent such as DMSO or acetonitrile, then dilute with buffer. Avoid DMSO with cysteine- or methionine-containing peptides, which it can oxidize.

Each product page lists the sequence and storage conditions for that compound. See also reading peptide sequences and formulas.

Chainwell products are for in-vitro laboratory research only and are not for human or veterinary use.