DHEA is an inactive form of the main androgen precursor (DHEA).

DHEA is produced in the adrenal glands, then sulphate is added to it, making it biologically inactive, a 'reserve' form. Once the body begins to need androgens, the sulphate group is split off, restoring the hormone's activity. Subsequently under the influence of reduction reactions slightly active DHEA is transformed into androstenedione with the consequent formation of testosterone - the male sex hormone.

This route of testosterone formation gives only a small amount of testosterone, but it is nevertheless sufficient for the female body.

DHEA is formed not only in the adrenal glands, but also in the ovaries (5% of the total amount). Its blood test replaces the urinary determination of 17α-ketosteroids. Reproductologists use the results of DHEA to establish the site of androgen synthesis: high levels of the hormone indicate preferential production in the adrenal glands and low levels in the sex glands. During pregnancy, the production of the hormone increases as a component of estrogen, which will be produced by the placenta.

A low concentration of DHEA is seen in delayed puberty, and vice versa in premature puberty. After puberty, the amount of the hormone decreases by about 3% per year. By the age of 90, it drops by about 90%.

An adrenal tumour (androsteroma), which produces a large amount of androgens, could cause an increase in the blood levels of DHEA. In this case there is an increase in testosterone in addition to DHEA.

A number of studies have shown that a low concentration of DHEA is associated with an increased risk of coronary heart disease.