I wanted to create a purple shampoo that was great for toning blondes + brunettes that was also sulfate-free... I’ve always had a hard time finding that combo. If you like ashy tones or even pastel lavender tones you can use this every time you shampoo. If you like neutral tones use it only when needed to cut brass. Use this with or without The One Purple Conditioner on natural or color treated hair.