Step 1 in Color Endure regimen: This color maintenance shampoo cleanse gently while protecting the vibrancy of color-treated hair with Multi-Spectrum Defense Complex, a three step defense system that prevents color loss and tonal change. pH 4.5-5.5. Contains Quadramine Complex, an exclusive blend of low molecular weight and size proteins. This balance of 19 essential amino acids (the building blocks of hair) adheres quickly and effectively to ensure maximum protection and reconstruction from the cuticle to the cortex.