Dihydrolipoic acid (DHLA) is a dithiol-containing carboxylic acid that is the reduced form of α-lipoic acid . It acts as a general antioxidant that is highly reactive against a variety of reactive oxygen species, including hydroxyl radicals, peroxynitirite, hydrogen peroxide, and hypochlorite, at concentrations ranging from 0.01-0.5 mM. At concentrations of 50-100 μM, DHLA triggers apoptosis of mouse embryonic stem cells and human cancer cells, suppressing proliferation.