The body produces DHEA in the adrenal gland using cholesterol as the starting material. DHEA levels peak in the second or third decade of life, after which decline begins. Roughly one-half of DHEA is lost in men by age 40. Reduced levels of DHEA signify reduced amounts of androstenedione, testosterone and other steroid hormone metabolites. Thus, the importance of DHEA in intense exercise and endurance training can hardly be overemphasized.