Table 2 Summary of research utilizing hair samples to investigate hair cortisol, chronic stress and mental well-being.

Intensive aerobic exercise, endurance sports

−Cortisol levels in the first to third 3-cm-long hair segments closest to the scalp

−Method includes hair segment washing with isopropanol, ball mill and steroid extraction using methanol, immunoassay (CLIA)

−Hair samples were from 304 amateur endurance athletes (long-distance runners, triathletes and cyclists) and 70 control individuals. Hair from the posterior vertex as close to the scalp

−The physical stress from intensive training and competitive races in endurance athletes was linked to increased cortisol levels

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Chronic stress on cardiovascular risk (coronary heart disease, stroke, peripheral arterial disease, diabetes mellitus and other chronic, noncardiovascular diseases)

−Cortisol levels in the 3-cm-long hair segment. Method includes hair segment washing and steroid extraction using methanol, ELISA kit (DRG Instruments)

−Approximately 150 hair strands cut from the posterior vertex, as close to the scalp from 283 participants

−High hair cortisol levels with an increased cardiovascular risk −No associations between hair cortisol levels and noncardiovascular diseases

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COVID-19 pandemic (sense of coherence, mental health)

−Cortisol levels in 3-cm hair. Method includes hair segment washing with isopropanol, ball mill and steroid extraction using methanol, radioimmunoassay (Orion Diagnostica)

−Hair samples were from 260 participants. Hair from the posterior vertex as close to the scalp

−Sense of coherence was significantly associated with anxiety mental health

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COVID-19 pandemic (depressive symptoms), mental health

−Cortisol levels in the 3-cm-long hair segment. Method includes hair segment washing and steroid extraction using methanol, LC–MS/MS

−Hair samples from 1,025 adults. Hair from the posterior vertex as close to the scalp

−Cortisol was positively and significantly associated with elevated depressive symptoms during the COVID-19

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COVID-19 pandemic (stress, and burnout, psychological distress, and any other mental health in a health workers)

−Cortisol levels in the 3-cm-long hair segment. Automated chemiluminescent method (Immulite 2000 autoanalyzer)

−Hair samples from 234 (68 men and 166 women) health workers from Hospital. Hair from the posterior vertex as close to the scalp

−Higher values in hair cortisol levels in the group with burnout. An association between perceived stress and hair cortisol levels was observed

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Chronic stress (myocardial infarction)

−Cortisol levels in the 1-cm-long hair segment. Method includes hair segment washing, ball mill and steroid extraction using methanol

−Hair samples from myocardial infarction [(acute myocardial infarction (AMI), n = 174)] and 3156 control individuals

−Higher levels of HCC were strongly and statistically significantly associated with current AMI status.

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Chronic stress and hair cortisol in children

−Extracting Cortisol from 1, 3 or 6 cm of hair, measuring HCC by LC−MS/MS

−Data from five countries with 1,455 participants.

−This review of nine studies found significant positive correlations between chronic stress, measured by stressful life events in the past 6 months and HCC

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Chronic stress (angiographically confirmed coronary atherosclerosis)

−HCC was assessed from scalp hair by ELISA

−500 angiographically confirmed coronary atherosclerosis patients and 500 age and sex matched control individuals

−HCC was significantly higher in patients with angiographically confirmed coronary atherosclerosis compared with control individuals

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Stress (bullying at school)

−HCC was assessed from scalp hair by ELISA

−The study included 659 11-year-old preadolescents

−Bully/victim status was linked to higher HCC, which in turn was associated with poorer executive function, highlighting the potential impact of chronic stress on preadolescent health and development

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