Cortisol, the stress hormone, can be found in hair.
- Cortisol is a hormone continuously secreted by the hypothalamic-pituitary-adrenal axis.
- Cortisol levels can be measured in blood, urine, and saliva.
- The concentration of cortisol in hair differs by sex and changes over the course of life.
“Hair cortisol concentration represents a potential biomarker of chronic stress. Yet previous research exploring the association between stress and hair cortisol levels has been limited to relatively small populations,” wrote Icelandic and Mexican scientists in work published in the journal PLOS Global Public Health.
1,279 participants
In this study, researchers collected hair samples from 881 women living in Mexico and 398 people living in Iceland. They analyzed the first three centimeters of their hair. All participants were also asked to complete a mental health questionnaire to assess their state of stress. The detected cortisol concentration was then compared to the volunteers’ responses.
A cortisol level of 24.3% in the hair
According to the results, the Mexican participants had a slightly higher level of cortisol in their hair than those residing in Iceland. According to the team, the most stressed people had a cortisol level of 24.3% in their hair. This study “supports the hypothesis that cortisol concentration in hair is a reliable biomarker for detecting chronic stress”, concluded the authors.
