reductions in testosterone and estrogen lead to fuzzy thinking and losses in a number of areas: cognitive function, memory, motivation and mood, immune-system function, and bone density. It is wise, after age fifty, to have your hormone levels checked and possibly restored, pharmaceutically, to physiological levels if you do not have a medical condition that precludes this. Hormone replacement therapy, in both women and men, can restore quality of life and energy in a way that nothing else seems to.