DHEA, also known as dehydroepiandrosterone, is synthesized in the adrenal cortex from cholesterol via pregnenolone by the action of an enzyme called cytochrome P450. It is the most abundant adrenal steroid in humans and is the precursor for many important steroid hormones which includes estrogen and testosterone. In contrast to cortisol and other adrenal steroids, DHEA levels decline with age. Levels of DHEA increase through the second decade of life and then begin to decline to negligible amounts at ages greater than 70 years. We experience a 50% reduction in DHEA levels between ages 20 and 40. Since DHEA is the major androgen precursor in humans, men have 30% higher DHEA levels than women throughout their lives.
