An Investigation of Hair Cortisol Concentration Across Body Sites and Within Hair Shaft

The study examined cortisol concentrations in hair from different body sites and along the hair shaft in 22 young adults, finding no significant differences along the shaft but higher concentrations in forearm hair compared to lower leg hair. This suggested a localized response and supported the idea of an independent peripheral HPA axis in hair follicles. The findings indicated that hair cortisol production was dynamic and site-specific, potentially offering localized stress responses without affecting systemic cortisol levels. Limitations included gender-specific hair length issues and a lack of diverse age representation, prompting recommendations for further research on the relationship between central and peripheral HPA axes.