The serum dehydroepiandrosterone sulfate (DHEA-S) test measures the level of the sulfur-containing (stable) form of the hormone DHEA. It is primarily produced in the adrenal cortex (95%), with smaller amounts produced in the ovaries and testes. DHEA-S is a reservoir or precursor to androgenic (male) hormones such as testosterone and androstenedione. Because it is primarily of adrenal origin and its levels are relatively stable throughout the day (without significant fluctuations), it is an excellent tool for assessing adrenal androgen production.