What does the Salivary Cortisol — Morning (on waking) test measure?

Why is Salivary Cortisol — Morning (on waking) measured?

The waking value anchors the diurnal curve and indexes the top of the daily rhythm. A robust morning rise is the expected physiological pattern; a blunted or absent morning peak is interpreted in functional practice as reduced HPA-axis reactivity, though this reading is not a recognised endocrine diagnosis. Genuine morning hypocortisolism suggestive of adrenal insufficiency must be confirmed with serum morning cortisol and dynamic testing rather than inferred from saliva.

Reference ranges

Standard reference

Highest value of the day; a representative waking interval is roughly 3.7–9.5 ng/mL, but the figure is specific to the time of collection relative to waking.

Functional medicine optimal

Functional practice favours a clear morning peak well above the later-day samples; a defined 'optimal' waking concentration is not standardised.

Units

ng/mL, nmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.