A controlled release formulation of lipoic acid is disclosed. The lipoic acid is combined with excipient materials in such a way that those materials provide for gradual release of the lipoic acid in a manner which makes it possible to substantially increase the period of time over which therapeutic levels of lipoic acid are maintained relative to a quick release formulation. These features make it possible to use lipoic acid to reduce serum glucose levels and maintain those levels over time thereby obtaining a range of desired therapeutic results.