Used in biochemical research as a derivatization agent for carboxylic acids, particularly in peptide synthesis and modification. Its guanidino group enhances water solubility and promotes interaction with biological targets, making it useful in the development of enzyme inhibitors and receptor ligands. Also explored in prodrug design due to its ability to improve cellular uptake and bioavailability. Commonly employed in mass spectrometry sample preparation to increase ionization efficiency of acidic compounds.