Blondes need to use clarifying shampoo more often

If you have chemically treated light hair, you need to use a clarifying shampoo more consistently. Dyed or highlighted hair particularly bleached hair becomes very porous, says Renk. So it can easily absorb unwanted yellowish tones from the outside environment, like from hairspray, perspiration, city smog and even minerals from your shower water. Using a clarifying shampoo weekly will help dissolve product and natural buildup, neutralizing those unwanted tones.