Investigation of cross-sectional and longitudinal associations between work-related burnout and hair cortisol: The Regensburg Burnout Project

•Sample consisting of a burnout and a healthy comparison group.•Assessment of hair cortisol and burnout symptoms at two time points (t1 & t2).•No cross-sectional associations between burnout and hair cortisol in total sample.•Negative longitudinal association between burnout (t1) and hair cortisol (t2).•Change in burnout symptoms from t1 to t2 was not related to change in hair cortisol.