If your hair is naturally blonde, color-treated blonde or gray ... Color-depositing shampoos add specific pigments (either purple, blue or green) onto the hair shaft to maintain your desired ...

those chic blue undertones. Plus, "a natural blonde could use it if their hair is feeling a little dull and they wanted a bit of vibrancy," Grummel says. How often should I use purple shampoo?

It's arguably blonde hair's biggest nemesis ... "If you leave a purple shampoo on for too long, your hair will have a blue-purple tinge to it," Irwin cautions. Never exceed the specific product ...