A method of identifying or evaluating synergistic combinations of actives such as skin-care actives that improve the metabolism of a cell and provides an advantage over using the actives alone. The method includes contacting cells with test agents, alone and in combination, and determining a response of the cells to the test agent(s), wherein the response corresponds to a change in a metabolic indicator associated with glycolysis and a change in a metabolic indicator associated with oxidative phosphylation.
