R(+)-Lipoic acid is the natural form of this vital antioxidant. It is the sole form produced in the body for use in the mitochondria. Conventional “lipoic acid” or “alpha lipoic acid” supplements are only 50% R(+)-lipoic acid; the other half of such supplements is the artificial S(-)-enantiomer. Research demonstrates that R(+)-lipoic acid is more potent that the S(-)-form, and that in some cases the S(-)-form interferes with R(+)-lipoic acid’s actions in the body.