All hair types can benefit form a treatment. Scalp treatments for dry or sensitive scalps. Hair treatments to suit all hair conditions and textures to help strengthen, repair, condition, add volume, de frizz, smooth, add shine. And yes hair dose dry out as much in Winter as summer. Treatments can be used weekly in the shower or as often as daily and left in, they all have a different purpose and feature..... just because your girlfriend uses a particular treatment this may not be the right one for you!!! All hair types and conditions are different