Proteins and peptides that are sold in liquid form/solution are sensitive to high temperatures, so are shipped on ice packs or dry ice. Lyophilized proteins and peptides are more stable and are shipped on ice packs or at room temperature.
Upon receipt, care should be taken to store these products as directed on the datasheet as quickly as possible. Most proteins can be snap-frozen in liquid Nitrogen and stored at -20ºC. Note: frost-free freezers should be avoided, as variations in temperature and moisture can damage the product.