.alpha.-Lipoic acid is a cyclic disulfide antioxidant that interconverts with its reduced dithiol form. It is an essential cofactor for decarboxylation reactions of the citric acid cycle and acts as a general antioxidant. AN-7 is a more lipophilic analog of .alpha.-lipoic acid with enhanced potency and 1.5-fold increased maximal capacity to stimulate glucose transport into myocytes. This identifies the analogs of lipoic acid as potential new treatments for diabetes.