122 citations
,
October 2010 in “Clinica Chimica Acta” Washing hair with water or shampoo lowers cortisol levels in hair.
22 citations
,
January 2010 in “Clinical Medicine Insights Endocrinology and Diabetes” Forearm hair has more cortisol than lower leg hair.
90 citations
,
July 2014 in “Conservation Physiology” Hair cortisol levels in brown bears can be affected by both long-term and short-term stress.
50 citations
,
November 2020 in “Physiology & behavior” People with depression often have higher hair cortisol levels, while those with PTSD tend to have lower levels, but more research is needed to understand this fully.
33 citations
,
January 2017 in “Psychoneuroendocrinology” Hair dyeing and washing frequency do not affect hair cortisol levels.
24 citations
,
October 2018 in “Addiction Biology” Alcohol dependence affects stress hormone levels more than childhood maltreatment.
22 citations
,
August 2016 in “European Eating Disorders Review” Adolescent girls with anorexia nervosa have lower hair cortisol levels than healthy and psychiatric peers.
21 citations
,
January 2016 in “NeuroImmunoModulation” Hair cortisol levels can indicate stress over the past three months.
1 citations
,
July 2023 in “Psychoneuroendocrinology” Hair cortisol is a reliable marker of long-term cortisol levels and is linked to daytime saliva cortisol but not morning levels.
January 2026 in “Psychoneuroendocrinology” Lye relaxers don't significantly change hair cortisol levels.
January 2026 in “Neuroscience Applied” Hair cortisol levels decrease as children age, stabilizing around age 4.
October 2025 in “Journal of Veterinary Diagnostic Investigation” Black hair in cats has higher cortisol levels than white hair.
June 2020 in “Authorea (Authorea)” First-time mothers had higher stress hormone levels in late pregnancy than mothers who had given birth before.
Distal hair cortisol is not a reliable measure of early pregnancy cortisol levels.
High-stress mothers had lower hair cortisol than low-stress mothers, and daughters' cortisol was linked to their stress response.
Hair hormone levels can indicate stress after a medically indicated abortion.
November 2025 in “Anxiety Stress & Coping” Higher anxiety symptoms and social behavior affect stress levels in hair.
February 2026 in “Psychoneuroendocrinology” Hair cortisol concentration partly reflects HPA axis regulation but doesn't capture all its complexities.
21 citations
,
January 2017 in “MethodsX” Methanol is better than isopropanol for washing grizzly bear hair to measure cortisol.
11 citations
,
April 2020 in “Animals” Moving horses to new places can increase their stress levels, as shown by higher stress hormone in their hair.
1 citations
,
September 2016 in “Brain Behavior and Immunity” Hair cortisol levels can indicate stress and are affected by washing frequency, not cosmetic treatments.
February 2026 in “TURKISH JOURNAL OF VETERINARY AND ANIMAL SCIENCES” Hair cortisol is better than blood cortisol for measuring long-term stress in pregnant goats.
September 2021 in “Psychoneuroendocrinology” Nurses had higher stress levels during intense phases of the COVID-19 pandemic.
30 citations
,
July 2016 in “Psychoneuroendocrinology” 24 citations
,
January 2019 in “Hormone Research in Paediatrics” 69 citations
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May 2016 in “General and Comparative Endocrinology” External factors can significantly affect hair cortisol levels, so it's not always a reliable stress marker.
157 citations
,
June 2015 in “Psychoneuroendocrinology” Hair cortisol and cortisone levels increase with age, are higher in diabetics, vary by gender, decrease with frequent hair washing, and are lower in winter.
118 citations
,
October 2014 in “Journal of Dairy Science” Tail switch hair is best for measuring cortisol in Holstein cows, with white hair and multiparous cows showing higher levels.
April 2026 in “Frontiers in Veterinary Science” Male cats have higher stress levels than females.
August 2021 in “Asian Journal of Pharmaceutical and Clinical Research” Plant extracts in shampoo improved hair thickness and density in men with hair loss.