In addition to the Moser Applications, those of skill in the art also are referred to U.S. Pat. Nos. 6,596,721; 6,441,168; and 6,271,374 which describe various methods and compositions for producing stable crystalline salts of 5-methyltetrahydrofolic acid and methods and compositions for producing stable forms of 6R tetrahdrofolic acid and methods and compositions for producing stable forms of 6S