K18's leave-in treatment mask works on the molecular level to repair hair damage in just four minutes. K18's K18PEPTIDE repairs damage from decades of bleach and color, chemical services, and heat -- with immediate and lasting results to restore strength, softness, smoothness, and bounce to hair.

How do I use it: Shampoo, do not condition. Towel-dry thoroughly. Apply three to nine pumps of K18 mini leave-in molecular repair hair mask based on your length and density, starting at the ends and working up towards the roots. Let sit for four minutes. Do not rinse out. Comb, add styling product and style as usual. Use for four to six washes, then as needed.

From K18.

Includes:

·1.7-fl oz Leave-In Molecular Repair Hair Mask