L-Phenylalanine methyl ester hydrochloride is widely used in the synthesis of peptides and pharmaceutical intermediates. It serves as a key building block in the production of aspartame, a popular artificial sweetener. Additionally, it is utilized in organic chemistry research for the preparation of chiral compounds and as a precursor in the development of various bioactive molecules. Its role in enzymatic reactions and as a substrate for studying enzyme mechanisms further highlights its importance in biochemical studies.