Our shampoo bars are 100% sulfate free. Some companies will say their bars are SLS free but not all consumers are aware there are many different sulfates that can be used in shampoo bars. The most common alternative to SLS is SCS (sodium coco sulfate) which has a pH of 7.5-10.5 and is composed of approximately 50% SLS. These two sulfates can cause drying and irritation to the hair and scalp.