K18

K18 rewrote the rules of bond repair with its patented K18Peptide, a bioengineered molecule that reconnects broken keratin chains from the inside out, no water, no rinse, no bowl required. The flagship Leave-In Molecular Repair Hair Mask is the four-minute treatment that turned the industry, and the Peptide Prep detox shampoo and clarifying wash round out the system for chemically treated, damaged, and overworked hair.

Hair Color USA stocks authentic K18 Leave-In Repair Mask, Peptide Prep shampoo, Damage Shield pH protective shampoo, and the professional chair-side chairside mist at salon pricing, with fast nationwide shipping from Jackson, Michigan. Stylists use K18 under color and after extensions, and retail clients reorder it because the before-and-after is undeniable. Shop the full K18 collection and add the four-minute repair your clients keep asking about.

K18 FAQ

What is K18 Leave-In Molecular Repair Hair Mask?

It is a leave-in treatment built on K18Peptide, a bioengineered molecule the brand says reconnects broken keratin chains inside the hair. It comes in a 5 oz size here. Apply it to towel-dried hair after shampooing and do not rinse.

Do I use K18 before or after conditioner?

K18's own directions call for applying it after shampoo and before any conditioner, on damp hair, then leaving it in. Follow the label for amount and timing, because using too much or skipping steps can change how the hair feels.

Is K18 a bond builder for bleached hair?

K18 is widely used to repair hair that has been stressed by lightening, heat, and chemical services. It is a leave-in molecular repair mask rather than a color product, so it is used after services or as ongoing home care.

How long does a 5 oz K18 mask last?

That depends on hair length, thickness, and how often you use it. Because the directions call for small amounts on damp hair, a 5 oz size can go a long way for shorter cuts. Longer or thicker hair will use it faster.