A method is described for determining a degree of damage to hair, which includes: registering light which is radiated by the hair sample while a hair sample is illuminated with light； based on the registered light, determining first regions of the hair sample which reflect the light with higher interference, and second regions of the hair sample which reflect the light with lower interference； and determining a degree of damage to the hair sample based on the extents of the first regions and of the second regions.
