Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) circulate in the blood mostly bound to albumin but with a small amount not bound to a protein. DHEA is cleared rapidly from the blood, with a metabolic clearance rate (MCR) in the range of 2000 I/day, but the clearance of DHEAS is much slower and its MCR is in the range of 131/day. DHEA and DHEAS interconvert and about 6% of DHEA will re-enter the blood as DHEAS, while 60-70% of DHEAS will re-enter as DHEA. Both DHEA and DHEAS can be converted in peripheral tissues to androstenedione, testosterone and dihydrotestosterone, and both are aromatized to estrogens. DHEAS enters the ovarian follicle and can be an important source of ovarian testosterone.