The present disclosure relates to a method of reducing heterogeneity in antibodies during culturing, wherein the heterogeneity is due to proportion of charge variant of the antibody. The disclosure also comprises a process of growing cells in a cell culture system that results in antibodies with the reduced heterogeneity. In one embodiment antibody heterogeneity is reduced by the addition of divalent transitional metal ions such as zinc (Zn2+) to the cell culture medium. In another embodiment antibody heterogeneity is reduced by decreasing the osmolality of the cell culture medium.
