From the Research
Cortisol is the best marker for measuring stress in the body, as it is directly produced through the hypothalamic-pituitary-adrenal (HPA) axis, which is the body's primary stress response system. This hormone is released by the adrenal glands in response to stress and can be measured through blood, saliva, or hair samples. For acute stress assessment, salivary cortisol testing is recommended as it's non-invasive and provides a snapshot of current stress levels, as shown in a study published in 2021 1. The test should be performed in the morning (between 8-9 AM) when cortisol levels are naturally highest.
Key Points to Consider
- For chronic stress evaluation, hair cortisol analysis is preferred as it reflects cortisol exposure over weeks to months, with a 3cm hair sample cut close to the scalp providing information about stress levels over the previous three months.
- Normal cortisol follows a diurnal pattern (highest in morning, lowest at night), and consistently elevated levels indicate chronic stress.
- Cortisol measurement can be used to assess the efficacy of interventions aimed at stress reduction, such as meditation and ashwagandha, as shown in studies published in 2021 2 and 2025 3.
- Other interventions like exercise, yoga, and meditation have also been shown to improve symptoms of depression and anxiety disorders, which are often associated with stress, as reported in a study published in 2019 4.
Measurement and Interpretation
- Saliva cortisol measurements using liquid chromatography tandem mass spectrometry (LC-MS/MS) is a reliable and fast non-invasive functional stress assay, which can be easily collected in daily practice and used for investigation and monitoring of stress response, as demonstrated in a study published in 2021 1.
- The correlation between changes in saliva cortisol and serum cortisol has been shown to be strong, making saliva cortisol a useful marker for stress assessment 1.