Abstract: An improved antiperspirant active material, and methods for its preparation, identification and use as well as cosmetic compositions containing said material are disclosed. Said material comprises a polymeric aluminum compound having the empirical formulaAl.sub.2 (OH).sub.6-a X.sub.awhere X is Cl, Br or I, a is about 0.3 to about 4; wherein said antiperspirant active material is further characterized by:(a) a Size Exclusion Chromatography Test band having a relative retention time corresponding to Band III of the Standard Basic Aluminum Chloride Solution Size Exclusion Chromatogram; and(b) a Band III Percent Aluminum Value of at least 20 percent.