None of the included subjects used CYP3A inducers according to the Flockhart CYP Drug Interaction Table.15 One of the anorexia nervosa patients used fluoxetine, a CYP3A inhibitor.15 The patient was not excluded since results showed higher 4βOHC concentration in underweight patients compared to normal‐weight subjects. Here, CYP3A4 is linked to anorexia nervosa.