The first step of the TRESemm? 7 Day Keratin Smooth System. This shampoo gently cleanses and removes any impurities, it is infused with Keratin and made with lower sulfates. This pearlised formula creates a rich and foamy lather whilst gently cleansing hair. Use with other TRESemme 7-day Smooth Keratin Smooth products. Gentle enough for everyday use and for use on colour treated hair.