Threonine is an essential polar amino acid with a hydroxyl group on its side chain, playing critical roles in protein synthesis, collagen formation, and immune function. It serves as a precursor for glycine and serine biosynthesis and is involved in mucin production for gut health. Naturally occurring in foods like meat, dairy, and legumes, it supports metabolic pathways including the threonine dehydrogenase route. Industrially used in supplements and animal feed, its stereochemistry (L-form) is biologically active. Soluble in water due to zwitterionic nature, it decomposes at high temperatures without boiling. Research confirms its safety as a dietary component with no significant toxicity at nutritional levels.