Anyway, the concept is stop washing your hair....with shampoo. Use apple cider vinegar. (I'm familiar with using this as a rinse to give the hair shine after shampooing, but I was not familiar with it being the shampoo.)Several people (who think a whole lot about these things) are concerned about the harshness of shampoo. Can't say I completely disagree. Shampoos do have sulfates which = detergent and that is a strong cleaning property. If you color your hair, some of these shampoos (even ones for color treated hair) will cause the color to fade. They can also be drying to the hair. Technology is offering us sulfate free shampoos and there are some very good ones out there.