Hair cortisol analysis: An update on methodological considerations and clinical applications

Background: Hair cortisol analysis is increasingly being appreciated and applied in both research and medicine, aiding endocrinologists with diagnosis. Content: We provide an overview of hair cortisol research in general and an update on methodological considerations including the incorporation of cortisol into hair, hair growth rates, and sampling procedures, mincing vs. grinding of samples during preparation for extraction, various extraction protocols, and quantification techniques. We compare the clinical utility and application of hair cortisol with traditional methods of measurement while acknowledging the limitations of analysis including variations in hair growth parameters. We explore the value of hair cortisol in cases of Cushing syndrome (particularly Cyclical Cushing), Adrenal insufficiency (including Addison's disease), therapy monitoring, cardiovascular disease, stress, and mental illness. Summary: Hair cortisol provides a unique objective biomarker for the analysis of endogenous cortisol levels for not only clinical diagnostic purposes but also in research. The use of hair cortisol has great potential for advancing patient care.