DHEA vs DHEA-S

DHEA and DHEA-S are two forms of the same adrenal hormone, differing by a single chemical attachment. That small difference changes how steady each one is in the blood, which is why a laboratory usually prefers to measure DHEA-S even though DHEA is the form most people have heard of.

What DHEA is

DHEA, short for dehydroepiandrosterone, is a steroid hormone made mainly by the adrenal glands, with smaller contributions elsewhere. It is often described as a precursor hormone because the body can convert it into other steroids, including certain androgens and estrogens. DHEA itself circulates at relatively low and fluctuating levels. Like cortisol and ACTH, DHEA follows a daily rhythm and can shift with stress, so a single DHEA measurement can be hard to interpret on its own.

What DHEA-S is

DHEA-S, or DHEA sulfate, is DHEA with a sulfate group attached. The adrenal glands convert much of their DHEA into this sulfated form. The attachment makes the molecule far more stable in the bloodstream: DHEA-S clears slowly and does not swing through the day the way DHEA does. As a result, DHEA-S circulates at much higher concentrations and stays comparatively steady from hour to hour. The body can remove the sulfate group to regenerate DHEA when needed, so DHEA-S also acts as a reservoir.

How the two relate

DHEA and DHEA-S are essentially the same hormone in two interconvertible states. The adrenal glands produce DHEA and sulfate a large portion of it to DHEA-S; the body can later remove the sulfate to return to DHEA. Because the great majority of the adrenal output exists as DHEA-S at any moment, DHEA-S serves as a stable marker of overall adrenal production of this hormone family, while free DHEA represents the smaller, more dynamic fraction. In effect, DHEA-S is the steady pool and DHEA is the changeable working form.

Why labs usually measure DHEA-S

The stability of DHEA-S is the main reason it is the preferred laboratory measurement. Because DHEA-S does not follow a strong daily rhythm and changes little over short periods, a single draw at almost any time of day gives a reasonably representative number. DHEA, by contrast, rises and falls through the day, so a one-off DHEA level is more affected by timing and stress and is harder to interpret. For most questions about adrenal androgen production, DHEA-S is therefore the more practical and reproducible test.

When each one matters

DHEA-S is the usual choice when a clinician wants to assess adrenal androgen production, because of its stability and because it points fairly specifically to the adrenal glands. It is among the markers considered in evaluations involving excess or deficient adrenal androgens. DHEA itself is measured far less often and tends to be reserved for specific situations a clinician identifies. In general, if you see a result for this hormone family on a panel, it is most likely DHEA-S.

How a report presents them

DHEA-S is reported in much larger units than DHEA, reflecting its higher circulating concentration. Reference ranges for DHEA-S are strongly age-dependent — they tend to peak in young adulthood and decline gradually with age — so results are always read against an age- and sex-matched range. The illustrative table below shows the general contrast rather than target values.

For background on adrenal hormones, see the hormones index; for sampling and timing, see the blood tests overview. Related conditions appear in the conditions index, and you can find other paired explainers in the comparisons index.

A note on interpretation

Because DHEA-S declines naturally with age, a value that would be unremarkable in an older adult could look different in a younger one, and vice versa. This is why a result viewed without its age- and sex-matched reference range can be misleading. The hormone is also one of several adrenal markers that clinicians read together rather than in isolation.