As the cortisol hormone level changes during the day, we listed below the Normal ranges used by medical laboratories to measure how normal or abnormal the cortisol result is?
Also, Laboratories may use different measuring units to express the concentration of cortisol, so that we ease the results and list the most common units to express the cortisol numbers, in conventional and SI units.
Normal Cortisol Levels in Plasma For Adults in μg/dL
| Testing Time | Cortisol Level |
| 8 AM–10 AM | 5 – 23 μg/dL |
| 4 PM–6 PM | 3 – 13 μg/dL |
Normal Cortisol Levels in Plasma For Children in μg/dL
| Testing Time | Cortisol Level |
| 8 AM–10 AM | 15 – 25 μg/dL |
| 4 PM–6 PM | 5 – 10 μg/dL |
Normal Cortisol Levels in Plasma For Adults in nmol/L
| Testing Time | Cortisol Level |
| Morning 8 AM–10 AM | 138 – 635 nmol/L |
| Evening 4 PM–6 PM | 83 – 359 nmol/L |
Normal Cortisol Levels in Plasma For Children in nmol/L
| Testing Time | Cortisol Level |
| Morning 8 AM–10 AM | 413 – 690 nmol/L |
| Evening 4 PM–6 PM | 140 – 280 nmol/L |
Normal Cortisol Levels in Plasma in nmol/L
| Testing Time | Cortisol Level |
| Morning 9 AM | 170 – 420 nmol/L |
| Evening 4 PM–6 PM | 83 – 360 nmol/L |
What Do Normal Cortisol Levels Mean?
The interpretation of cortisol level from a medical perspective,
At the morning cortisol level should be higher than any other time, the reason is to help human body get more energy by delivering more fat and glucose to the body cells, however, as the day going on the body get tired and going to the rest status, hence the adrenal gland tend to secrete lower amount of cortisol.
Meaning of cortisol reference range:
Medical Scientists set two limits that cortisol level should be inside whenever the time be the morning, afternoon or evening.
Measuring units and concentration expressions for cortisol reading
Mmol/L is a short form of Milli-mol cortisol per one liter of blood.
nmol/L is a short form of nano-mol of cortisol per one liter of blood.
Concentration doesn't mean the whole amount of cortisol in our bodies but the amount in a single volume of blood, and Yes it's helpful for doctors to know the cortisol levels.
If you have cortisol results and need to get professional insights, please send us your results privately or in comments, we promise high-value medical information.
