5-Hydroxy-DL-lysine hydrochloride is a non-proteinogenic amino acid derivative, specifically the racemic mixture of the hydroxylated form of lysine. It is characterized by the presence of a hydroxyl group at the 5-position of the lysine side chain. This compound is typically supplied as a hydrochloride salt to enhance its stability and solubility in aqueous solutions. This modified amino acid serves as a valuable building block in biochemical and pharmaceutical research. Its primary application lies in the study of collagen and elastin biosynthesis, as hydroxylysine is a crucial post-translational modification in these structural proteins. It is used as a precursor or standard in metabolic pathway investigations and in the synthesis of peptides designed to mimic or study collagen-like structures. Additionally, it finds utility as a chiral synthon in organic synthesis for the preparation of more complex molecules. As a research chemical, it is handled in laboratory settings. Standard safety precautions for handling amino acids and hydrochloride salts should be observed, including the use of personal protective equipment to avoid inhalation or contact with skin and eyes.