L-Cysteic acid is widely used in the biochemical and pharmaceutical industries. It serves as a precursor in the synthesis of various bioactive compounds, such as taurine derivatives, and is employed in the production of certain drugs and supplements. In research, it is utilized as a standard in amino acid analysis and protein sequencing due to its distinct properties as an oxidized form of cysteine. Additionally, it finds application in the formulation of cosmetics and personal care products, where it acts as a skin-conditioning agent, humectant, and antioxidant. Its role in studying oxidative stress, protein oxidation, and metabolic pathways also makes it valuable in scientific studies related to cellular processes.