Alpha Lipoic Acid Sustain 300 is in a sustained release format to minimize gastric irritations and blood sugar fluctuations. Alpha Lipoic Acid is a disulfide molecule (containing two thiol groups). A thiol (or -SH) consists of a sulfur and a hydrogen atom. This unique antioxidant is both lipid and water soluble, a potent promoter of glutathione synthesis and cofactor in energy production, Enhanceing to regulate glucose metabolism. Jarrow Formulas Alpha Lipoic Acid is made in Europe. Biotin is added for optimum ALA activity.