Do Follicles Matter? Testing the Effect of Follicles on Hair Cortisol Levels

January 2020 in “ Conservation Physiology ”

Agnieszka Sergiel, Marc Cattet, Luciene Kapronczai, David M. Janz, Nuria Selva, Kamil A. Bartoń, Jon E. Swenson, Andreas Zedrosser

hair follicles hair cortisol concentration HCC cortisol secretion

Studysummary This study found that cortisol concentrations were significantly higher in hair samples with follicles compared to those without, suggesting potential confounding in stress assessments using different hair sampling methods. Our plain-language summary of this paper — not a Tressless recommendation.

The study on 30 Scandinavian brown bears found that hair cortisol concentration (HCC) was significantly higher in samples with follicles, with a 6.6% increase compared to those without. This indicated that follicles could influence HCC, potentially due to residual blood or cortisol production within the follicle. The study highlighted the importance of standardizing hair collection and preparation methods to ensure valid comparisons across studies. Additionally, it noted that HCC varied with age and sex, increasing in older female bears but decreasing in males, with the follicle effect diminishing with age. The review of 77 papers reinforced the need for standardized guidelines in hormonal analyses using hair.

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research Influence of External Factors on Hair Cortisol Concentrations

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research Sources of Variation in Hair Cortisol in Wild and Captive Non-Human Primates

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This study observed that hair cortisol concentrations in primates are influenced by factors such as age, sex, hair growth rates, and sampling methods, which must be accounted for in research designs.

research Quantifying Long-Term Stress in Brown Bears with Hair Cortisol Concentration: A Biomarker That May Be Confounded by Rapid Changes in Response to Capture and Handling

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research The Hair Follicle as a Dynamic Mini-Organ

759 citations , February 2009 in “Current Biology”

This review summarizes fundamental concepts and recent advancements in hair follicle biology, including insights from mouse models into broader molecular and cellular processes relevant to regeneration and development.

research Complex Hair Cycle Domain Patterns and Regenerative Hair Waves in Living Rodents

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research Measurement of Cortisol in Human Hair as a Biomarker of Systemic Exposure

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research Human Hair Follicles Display a Functional Equivalent of the Hypothalamic-Pituitary-Adrenal (HPA) Axis and Synthesize Cortisol

489 citations , June 2005 in “The FASEB Journal”

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research In Vitro Metabolism of Progesterone by Canine Hair Follicle Cells

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