Dehydroepiandrosterone is produced by the adrenal glands. It is a product of cholesterol metabolism. DHEA’s direct mechanism of action is unknown. DHEA levels begin to increase during puberty, peak by age 30, then decline by about 10% each decade, plateauing around age 80. The age-related decline in DHEA is associated with a decrease in muscle mass and bone density. Both DHEA and testosterone are converted to the active androgen dihydrotestosterone in the peripheral tissues. Many changes associated with aging, such as reduced immune function, obesity, diabetes and increased risk for cancer, are associated with decreasing levels of DHEA, according to animal studies.