Fmoc-His(Fmoc)-OH is widely used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS) methods. It serves as a protected form of histidine, where the Fmoc (fluorenylmethyloxycarbonyl) groups protect the amino and imidazole functionalities during the peptide chain assembly. This protection ensures selective deprotection and prevents unwanted side reactions. It is especially valuable in synthesizing peptides containing histidine residues, which are common in biologically active peptides and proteins. Its application is critical in pharmaceutical research, drug development, and the production of peptide-based therapeutics, where precise control over amino acid incorporation is essential.