Disclosed herein are methods for increasing the overall vigor of a subject, and/or vigor of target tissues of a subject. Exemplified herein is the utilization of pyrimidine derivatives which act to stimulate stem cell proliferation. In addition to increasing vigor, such stem cell proliferation agents (SCPA) may be used to enhance and/or improve the outcome of other therapies, and may be used in psychiatric applications. Increasing vigor in subjects is not necessarily targeted to the treatment of a disease, thus, the methods can include administration to clinically healthy animals.
