There is a growing body of evidence to suggest that early life stress can have detrimental effects on a child's physical and mental health. Hair cortisol concentrations are increasingly accepted as a cumulative measure of stressful experiences but they are understudied in preschool children. In this episode, we meet Professor Sunny Anand from Stanford University School of Medicine who developed a sensitive assay for hair cortisol concentrations. He and his team took hair samples from children aged 1-4 years in order to uncover psychosocial and demographic factors associated with this measure of physiological stress. Have a listen! Related Article: https://www.nature.com/articles/s41390-019-0691-2