DHEA-S as a Marker: What the Number Means

DHEA-S is one of the few markers where the reference range on the report is nearly useless on its own. A value of 120 µg/dL is unremarkable in a 68-year-old and a genuine finding in a 32-year-old, and most laboratories print a single adult range that spans both. It is also the marker most often used to justify a supplement, on evidence that is considerably weaker than the confidence with which it is usually recommended. Both of those are worth understanding before you act on a number.

What DHEA-S is, and why it is the form measured

DHEA (dehydroepiandrosterone) is produced mainly by the adrenal cortex, in the zona reticularis, under ACTH control. Most of it is immediately sulfated to DHEA-S, and the sulfated form is what circulates in quantity.

The sulfate group is what makes it useful as a marker. DHEA itself is secreted in pulses and follows a diurnal rhythm, so a single measurement tells you as much about when you drew it as about the person. DHEA-S has a far longer half-life, circulates at much higher concentrations, and does not vary meaningfully across the day — one draw, at any reasonable time, gives a stable picture of adrenal androgen output. It is the practical clinical measure not because it is the active molecule, but because it is the readable one.

The two interconvert: tissues that need DHEA desulfate the circulating pool locally, so DHEA-S functions as a reservoir the body draws on rather than an end product.

What it is a precursor to

DHEA sits upstream of both androgens and oestrogens. In peripheral tissues it can be converted onward to androstenedione, then to testosterone, and by aromatase to estradiol. This local production — hormone made and used inside the same tissue, without ever appearing meaningfully in blood — is why DHEA matters more than its own weak receptor activity would suggest.

The clinical consequence is asymmetric between the sexes. In men, the testes produce the overwhelming majority of circulating testosterone, so adrenal precursor supply is a minor contributor. In postmenopausal women, the ovaries have largely stopped, and adrenal DHEA becomes the principal raw material for whatever androgen and oestrogen activity remains in peripheral tissue. That is the mechanistic reason DHEA is discussed far more seriously in women's medicine than in men's. The DHEA precursor cascade follows the steps in detail.

The age curve

DHEA-S peaks in the twenties and falls steadily thereafter — a decline described decades ago and confirmed repeatedly since (Orentreich et al., J Clin Endocrinol Metab 1984). Unlike testosterone in men, the fall is steep and near-universal, which is what earned it a place in ageing research.

Ranges vary by assay and by sex, and the number that matters is where a person sits within the band for their own age. A result reported as "normal" against a 20-70 adult range is not an interpretation. Optimal versus normal lab ranges covers why that distinction keeps mattering.

Reading the number

• Below the age-adjusted range: confirmed low. Worth asking why — adrenal insufficiency, long-term corticosteroid use, chronic illness, or significant HPA suppression are the causes that change management.
• Lower third of the age-adjusted range, with symptoms: the borderline zone where supplementation is most often discussed and where the evidence is weakest.
• Mid-range: unremarkable. No intervention indicated.
• Markedly elevated: uncommon, and it is the direction that warrants investigation rather than reassurance — congenital adrenal hyperplasia, PCOS, or an adrenal tumour.

A low DHEA-S is also a clue about the HPA axis generally, since the same ACTH drive that governs cortisol governs adrenal androgen output. Reading it alongside a cortisol pattern says more than reading it alone — the HPA axis in depth covers that interaction.

What supplementation has and has not shown

This is where honesty is more useful than enthusiasm, because the evidence splits cleanly into two groups.

In people with adrenal insufficiency — where DHEA production is genuinely absent rather than merely reduced — replacement produced measurable improvements in wellbeing and mood in randomised work, particularly in women (Arlt et al., N Engl J Med 1999). This is the clearest indication and the one with the strongest rationale: you are restoring something that is missing.

In healthy older adults with age-related decline, the picture is much less impressive. A randomised trial of DHEA in elderly men and women found no meaningful benefit on body composition, physical performance, insulin sensitivity or quality of life (Nair et al., N Engl J Med 2006). Earlier work in older adults reported more modest, mixed effects, with any signal strongest in older women (Baulieu et al., DHEAge study). Trials in postmenopausal women looking at sexual function have likewise produced modest and inconsistent results (Davis et al., DHEA in postmenopausal women).

The honest summary: DHEA is a well-supported replacement therapy in adrenal insufficiency and a weakly supported optimisation therapy in everyone else. A low number in an otherwise healthy 55-year-old is a normal finding for a 55-year-old, and treating the number is not the same as treating the person.

When supplementation is reasonably considered

Given the above, the situations where a physician might reasonably discuss it are narrower than the marketing suggests:

• Confirmed adrenal insufficiency
• A DHEA-S clearly below the age-adjusted range, with symptoms that fit — fatigue, low mood, reduced libido
• Postmenopausal women, where adrenal precursor supply carries more weight
• Alongside evaluation of a broader HPA pattern rather than as an isolated intervention

Dose is a physician's decision and is typically substantially lower in women than in men, because the same amount of precursor produces a much larger relative change in a system with little other androgen input. DHEA supplementation in men covers the male side, where the case is weaker still.

Monitoring, and what actually goes wrong

• Retest at two to three months. DHEA-S responds quickly, so this interval is about confirming the level, not waiting for an effect.
• Test the downstream hormones, not just DHEA-S. Testosterone and estradiol are where the conversion shows up, and they are where side effects come from.
• Watch for androgenic effects in women — acne, oily skin, facial hair, scalp hair thinning, voice change. These are the most common reason to stop, and the voice change is the one that does not fully reverse. Androgens in women covers the same territory.
• Watch estradiol in men, since aromatisation of the extra precursor is a real route to symptoms.
• Supplement quality is genuinely variable, because DHEA is sold as a dietary supplement in the United States and is not subject to the same content verification as a prescription. Third-party testing is worth insisting on.
• Competitive athletes should not take it. DHEA is a prohibited substance in most sporting bodies, and there is no exemption for buying it over the counter.

Bottom line

DHEA-S is the stable, measurable form of the adrenal precursor DHEA, which is why it is the number on the panel. It falls steeply and predictably with age, so it can only be read against an age-adjusted range, and a "normal" flag against a wide adult range means very little. Its clinical weight is highest in postmenopausal women and in adrenal insufficiency, where replacement is well supported; in healthy older adults, the trial evidence for supplementation is modest at best. Where it is used, the useful follow-up markers are testosterone and estradiol, and the side effects to watch for are androgenic and mostly in women. If you want your own result read in context rather than against a range that spans fifty years, the 60-second assessment is the place to start.

Educational content, not medical advice. Laboratory interpretation and any treatment decision are made by a licensed physician after individual evaluation. Individual results vary.