K18 Leave-In Molecular Repair Hair Mask. 4-minute leave-in treatment to clinically reverse hair damage, An At-home Leave-In Treatment infused with the patented K18Peptide that renews hair to its most youthful, healthy state. Works to repair even the most extreme damage caused by bleach and color, chemical services, and heat. Creates Like Hair Like New: Traveling into the inner-most layers of hair to reach the core polypeptide chains our revolutionary K18Peptide is just the right size and makeup to reconnect broken chains responsible for hair strength and elasticity. Renews All Hair Types: K18 doesnt just hide damage or patch it up leaving hair brittle, it transforms even the most extreme damage into hair that looks and feels like new. K18 works on all hair types, all generations, all types of expression Lasting Results That Won't Wash Away: The K18Peptide mimics the natural building blocks of hair and therefore is recognized as naturalso its able to integrate itself with the keratin chains to rebuild and restore hair immediately and over time.