K18 is a haircare brand that offers a leave-in molecular repair hair mask treatment designed to repair damage caused by bleach, color, or heat and add strength, softness, shine, and bounce to hair. The product features the proprietary K18Peptide, which is a patented molecular breakthrough clinically proven to reverse hair damage from bleach, color, chemical services, and heat in just 4 minutes. K18 works at a deeper level to molecularly change and repair the polypeptide chains that have been broken, as well as reconnecting the disulfide bonds. The K18Peptide works at the innermost layers of the hair fiber to reconnect broken polypeptide chains, restoring hair strength and elasticity. The product is a less-straightforward treatment system than others, and it is a leave-in treatment that is designed to help repair damage caused by bleach, color, or heat. The K18 hair mask is suitable for every type of hair that has been damaged due to chemical treatments, including curly and coily hair. The product is applied after shampooing and towel-drying hair until damp, and it is left in for four minutes to work its magic. The K18 hair mask has received positive reviews from customers, with many reporting that it has helped to repair their damaged hair and improve its overall health.