Trehalose dihydrate is a natural disaccharide consisting of two glucose molecules joined by an alpha-alpha-1,1-glycosidic bond. It is commonly found in many organisms, including bacteria, fungi, plants, and invertebrates, where it plays a protective role against environmental stresses such as dehydration and freezing. It’s used as a stabilizer in the pharmaceutical industry to protect proteins, vaccines, and other biopharmaceuticals from degradation during storage and transportation.