Mixing and storage

In laboratory handling the powder is kept frozen at about minus 20 degrees, protected from light and moisture, and the mixed stock is kept cold at 2 to 8 degrees. Powder sold under this name comes as a lyophilised solid in vials of a few milligrams. The handling point that matters most is simpler than any of that: this is a 32 residue designed construct whose identity and purity you cannot check by eye, and everything about its effect depends on the intact peptide, since fragments behave differently. That is a laboratory question, answered with laboratory equipment.