The normal cortisol level for a woman varies depending on the time of day and the type of test. Cortisol levels are usually highest early in the morning and lowest around midnight. For most tests that measure cortisol levels in the blood, normal ranges are:

• 6 to 8 a.m.: 10 to 20 micrograms per deciliter (mcg/dL)
• Around 4 p.m.: 3 to 10 mcg/dL

Normal values for a blood sample taken at 8 in the morning are 5 to 25 mcg/dL or 140 to 690 nmol/L. Normal values depend on the time of day and the clinical context. Normal ranges may vary slightly among different laboratories.

It is important to note that cortisol levels can be affected by many conditions, such as physical or emotional stress, strenuous activity, infection, or injury. Women in their last three months of pregnancy and highly trained athletes may have higher-than-normal levels of cortisol. Other reasons why cortisol levels may be higher than normal include depression, alcoholism, malnutrition, and panic disorder. A number of medicines, especially oral contraceptives and any medicine that contains glucocorticoids, or steroid hormones similar to cortisol, can also affect cortisol levels.

If you are concerned about your cortisol levels, it is best to consult with a healthcare provider who can interpret your results and let you know if you need further testing.