K18 Biometric Hair Science Molecular Repair Hair Mask is a revolutionary leave-in hair treatment that works at the molecular level to repair damaged hair by restoring broken keratin chains, penetrating deep into the hair structure to improve strength, elasticity, and smoothness, ideal for hair damaged by coloring, heat styling, or chemical treatments, delivering healthier, shinier, and more manageable hair with visible and long-lasting results, featuring a lightweight formula suitable for frequent use, and free from sulfates, parabens, and gluten, making it safe for all hair types including color-treated and chemically processed hair.