Diurnal Cortisol Curves

A commonly used tool for assessing adrenal hormones is a diurnal cortisol curve. This curve is derived from taking four daily saliva collections – typically done upon waking, before lunch, before dinner and before bed – and charting them on a 24-hour graph.

The resulting curve – also called a four-point cortisol curve or circadian cortisol pattern – reveals cortisol levels throughout the day and allows health care providers to pinpoint issues with adrenal gland function. 





This pattern shows a normal rise in cortisol production within 30 minutes of waking for the day. Cortisol levels then drop throughout the day, reaching their lowest point at bedtime.






Diurnal Cortisol Patterns with Adrenal HPA Axis Dysfunction

Cortisol production is normally at its highest 30 minutes after waking and declines steadily during the day, reaching its lowest point at bedtime. Those with adrenal gland dysfunction generally have irregularities in their diurnal cortisol curves. Some common examples are shown below.  





Overall higher than normal cortisol production throughout the day can result from prolonged stress demands. General symptoms include feeling “tired but wired,” food cravings, insomnia and anxiety.










The pattern for chronic fatigue shows an elevated morning cortisol with levels dropping off rapidly during the day. General symptoms include mid-day energy drop, drowsiness and poor exercise recovery.










The burnout pattern, also commonly called “adrenal fatigue” is really a reflection of low overall cortisol during the day. General symptoms include day-long fatigue, irritability, food cravings, insomnia and exhaustion.






Many ZRT saliva and saliva/blood spot combination profiles, as well as several dried urine profiles, include the diurnal cortisol curve. Just look for the Cx4 (cortisol x 4) indication in the profile. Download a complete list of profiles below. 

Guide: What Test Results Can Tell You – Common Diurnal Cortisol Curves

Download: ZRT Overview of Profiles

Learn More About Hormones & Diurnal Curves

Cortisol Awakening Response

How Diurnal Curves Affect Sleep

Diurnal Curves for Chronic Stress

Diurnal Cortisol – Saliva vs Urine