As your highlights start to grow out so does that cool ashy blond color fade. A number of things may contribute to this fading color. Swimming, water with chemicals in it, shampoo, conditioner, styling aids with yellow pigment can wear down your blond and leave a brassy, dull yellow that takes on a flat look, not what you want!
You can protect and maintain your preferred color and neutralize the dull yellow before it starts by using a blonding shampoo.
Try blue, silver or purple shampoos and conditioners. It is best to start using a blonding shampoo soon after your salon visit, using it twice a week. If it has been a month or more you could use it 3-4 times at first then back off to twice a week depending on how often you shampoo. Let the shampoo or conditioner sit on your hair for 5 minutes if possible depending on your shampooing frequency. You should see a difference immediately.
I have found a few that I like and recommend, Matrix So Silver, Schwarzkoph Silver Shampoo, Joico Color Balance Blue, and Tressa Violet Wash.
