K18 Leave-In Molecular Repair Hair Mask 150ml is the salon-grade size of K18's flagship bond-repair treatment — a leave-in mask powered by the patented K18PEPTIDE™ that works at a molecular level to reconnect broken polypeptide chains and disulfide bonds in damaged hair. Just four minutes per application restores strength, softness and elasticity. The 150ml format is the professional and committed-home-user size.
About K18
K18 is an American haircare brand founded by Suveen Sahib and Britta Cox in Los Angeles, built on more than a decade of biotechnology research into hair-bond repair. The brand's K18PEPTIDE™ is a bioactive peptide designed to reconnect the broken keratin chains inside the hair fibre — a different mechanism from traditional protein-fill or oil-based repair treatments. The Leave-In Molecular Repair Mask is the brand's flagship product and the cornerstone of its protocol.
Key benefits
- Molecular bond repair: K18PEPTIDE™ reconnects broken polypeptide chains and disulfide bonds — the structural bonds responsible for healthy, springy hair.
- Restores elasticity: Hair regains bounce, stretch and resilience after just four minutes.
- Reverses chemical and heat damage: Clinically proven to repair damage from bleach, colour, perms, relaxers and heat styling.
- Leave-in formula: No rinsing required — the peptide continues to work inside the hair fibre after application.
- Builds with use: The first 4–6 applications form the brand's recommended "repair phase"; after that, weekly maintenance use keeps hair in optimal condition.
Who it's for
This mask is best suited to anyone with damaged hair from bleaching, colouring, chemical services or frequent heat styling — particularly those whose hair has lost springiness, breaks easily, or feels rough at the ends. Suitable for all hair types and textures.
How to use
- Shampoo the hair as usual. Skip conditioner for the first 4–6 applications.
- Towel-dry until damp, removing excess water.
- Apply a small amount to the mid-lengths and ends, working through with the fingers.
- Wait 4 minutes for the K18PEPTIDE™ to penetrate and repair.
- Do not rinse. Style as usual.
- Repeat after every shampoo for the first 4–6 washes; thereafter, use weekly to maintain bond integrity.
Size: 150ml. For external use on the hair only.
Related Products
