In postmenopausal women, all estrogens and nearly all androgens are made locally in peripheral target tissues from the inactive adrenal steroid precursor dehydroepiandrosterone (DHEA). In adult men, approximated 50% of androgens are made locally. This new section of endocrinology, which describes the local formation of sex steroids, has been named intracrinology. In fact, all the enzymes required to make androgens and estrogens are expressed in a cell-specific fashion, thus permitting local control of steroid formation and action. The local inhibition of sex steroid formation or action has shown important benefits in the treatment of hormone-sensitive cancers, including significant prolongation of survival and even curing localized disease. On the other hand, exogenous DHEA provides important advantages in postmenopausal women because it compensates for the declining secretion of DHEA by the adrenals with age. The benefits of DHEA include increased bone mineral density, muscle mass, well-being, and libido, as well as beneficial effects against skin atrophy, type 2 diabetes, and obesity.