DHEA-S is produced primarily by the adrenal zona reticularis.

Dehydroepiandrosterone sulfate (DHEA-S) is widely recognized as a stable and reliable biomarker for assessing the functional capacity of the adrenal cortex, specifically the zona reticularis.

Mechanistic basis of production

The production of DHEA-S is highly localized within the adrenal gland, specifically the zona reticularis (ZR), the innermost layer of the adrenal cortex.

• Enzymatic specificity: The ZR expresses a unique profile of enzymes, most notably CYP17A1 (17α-hydroxylase/17,20-lyase) and its cofactor cytochrome b5 (CYB5A). This combination favors the conversion of 17-hydroxypregnenolone into DHEA.
• Sulfation pathway: The final conversion to DHEA-S is catalyzed by SULT2A1 (sulfotransferase family 2A member 1), an enzyme almost exclusively localized to the ZR.
• Functional compartmentalization: The ZR maintains low levels of 3β-HSD (3β-hydroxysteroid dehydrogenase), an enzyme that would otherwise divert precursors toward cortisol or aldosterone. This specific enzymatic environment ensures that the ZR is the nearly exclusive source of DHEA-S, which accounts for approximately 95–99% of its circulating levels in women.

Clinical evidence for adrenal reserve

In clinical practice, DHEA-S serves as a robust indicator of adrenal androgenic output and overall adrenal reserve.

• Predicting adrenal integrity: Research involving patients at risk for secondary adrenal insufficiency shows that baseline DHEA-S levels correlate with the cortisol response during low-dose cosyntropin (ACTH) stimulation tests. A DHEA-S level within the age- and sex-adjusted normal range often indicates an "intact" adrenal reserve, while low levels suggest HPA axis impairment.
• Diagnostic utility: DHEA-S is used to differentiate between causes of hypercortisolism. It is typically suppressed in cases of autonomous cortisol-producing adrenal adenomas (due to ACTH suppression) but remains normal or elevated in pituitary-dependent Cushing’s disease.
• Stability as a marker: Unlike DHEA or cortisol, which exhibit significant diurnal variation, DHEA-S has a long half-life (approximately 15–20 hours) and high serum concentrations, making it a stable marker of daily adrenal activity rather than a snapshot of a specific moment.

Bottom line

DHEA-S is a validated marker of adrenal androgen production and functional reserve. Its clinical utility stems from its nearly exclusive production in the adrenal zona reticularis and its high degree of stability in the bloodstream, providing an integrated view of HPA axis health.