L-Lysine ethyl ester dihydrochloride is widely used in biochemical research and pharmaceutical applications. It serves as a key intermediate in the synthesis of peptides and proteins, particularly in solid-phase peptide synthesis (SPPS). Its ester form enhances solubility and reactivity, making it suitable for coupling reactions. In the pharmaceutical industry, it is utilized to develop prodrugs, improving the bioavailability and stability of active compounds. Additionally, it is employed in the study of enzyme mechanisms and as a building block for modified amino acids in drug design. Its role in enhancing drug delivery systems and therapeutic efficacy makes it valuable in medicinal chemistry.