K18 Leave In Molecular Repair Hair Mask is an at-home leave-in treatment infused with patented K18Peptide™ that works to repair even the most extreme damage, renewing hair to its most youthful, healthy state. Traveling deeper into the inner layers of hair than traditional repair products, our revolutionary patented K18Peptide™ is just the right size and makeup to fit in and reconnect broken keratin chains, renewing hair with strength, softness, smoothness, and bounce. You can feel and see the difference with the first use. See the dosage chart for exact usage. For best results, use K18 Leave In Molecular Repair Hair Mask for the first 4-6 consecutive washes, then every 3-4 washes as needed to maintain hair strength.