Ac-Arg-OH dihydrate is widely used in peptide synthesis as a building block for creating complex peptides and proteins. It serves as an N-protected form of arginine, with the acetyl group on the alpha-amino group to prevent unwanted reactions during synthesis. The arginine side chain may require additional protection depending on the synthesis method. This compound is particularly valuable in solid-phase peptide synthesis (SPPS), where it helps in the stepwise assembly of peptide chains. Its application extends to the production of bioactive peptides, which are used in pharmaceutical research and drug development. Additionally, it plays a role in studying protein-protein interactions and enzyme mechanisms due to its ability to mimic natural amino acid sequences.