Fmoc-5-Hydroxy-L-tryptophan is primarily used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It serves as a protected form of 5-hydroxy-L-tryptophan, allowing for the incorporation of this amino acid into peptide chains without interference from the hydroxyl group. This is crucial in the synthesis of complex peptides and proteins where 5-hydroxy-L-tryptophan plays a significant role, such as in the study of enzyme mechanisms, receptor-ligand interactions, and the development of therapeutic peptides. The Fmoc group provides temporary protection during the synthesis process and can be removed under mild conditions, ensuring the integrity of the peptide structure. Additionally, this compound is valuable in research focused on the biosynthesis and function of serotonin and other tryptophan-derived metabolites, aiding in the exploration of neurological and psychiatric disorders.