Blonde Enhancer™ Toning Shampoo deposits just the right amount of purple to tone down the brassiness of any blonde. Whether your blonde comes naturally or from your stylist, root to tip or balayage, even if you're proudly grey, 4P shampoo will help keep your color cool. Blonde Enhancer™ Toning Shampoo deposits just the right amount of purple to tone down the brassiness of any blonde. Whether your blonde comes naturally or from your stylist, root to tip or balayage, even if you're proudly grey, 4P shampoo will help keep your color cool.