Why Use 7 Day Keratin Smooth Shampoo? Infused with keratin and made with lower sulphates*, this product gently cleanses and removes impurities. For up to 7 days of salon-smooth styles**, use as the first step with 7 Day Keratin Smooth Conditioner and 7 Day Heat Activated Treatment. Gentle enough for everyday use and on colour treated hair. *vs TRESemmé leading shampoo **Up to 4 washes with system usage.