K18 Leave-In Molecular Repair Hair Mask 15ml

K18 Leave-In Molecular Repair Hair Mask 15ml is a four-minute leave-in repair treatment from the cult American haircare brand. Built around the brand's patented K18Peptide, it's designed to reverse damage from bleach, colour, chemical services and heat — restoring strength, softness and bounce to compromised hair.

About K18

K18 is the American haircare brand co-founded in 2020 by Suveen Sahib and Britta Cox, built around its patented bioactive K18Peptide. The brand became a viral hit through professional hairdressers who saw repeatable, dramatic improvements on damaged hair — and is now stocked across professional salons and prestige beauty retailers worldwide.

Key benefits

• Patented K18Peptide reconnects broken keratin chains in the hair fibre.
• Reverses damage from bleach, colour, chemical relaxing, perming and heat styling.
• Leave-in formula — no rinsing required after the 4-minute wait.
• Restores strength, softness and bounce on damaged hair after consistent use.
• Vegan and cruelty-free per the brand.
• Travel-friendly 15ml mini — handbag, gym bag and weekend-away friendly.

Key ingredients

• K18Peptide (sh-Oligopeptide-78): the brand's patented active — penetrates the hair to reconnect broken keratin chains.
• Behentrimonium chloride: conditioning agent that smooths and softens the hair fibre.
• Hydrolysed wheat protein: supports hair strength and condition.
• Tocopherol (vitamin E): antioxidant support.

Who it's for

Anyone with chemically-damaged hair — bleached, coloured, permed, relaxed — and anyone whose hair feels weak or limp from heat styling. The 15ml format makes a useful starter or top-up between full-size bottles.

How to use

1. Wash the hair with shampoo as usual; do not condition.
2. Towel-dry the hair until just damp.
3. Dispense a small amount onto the palms — typically a 5p-sized amount for shoulder-length hair.
4. Apply evenly through the lengths and ends, avoiding the scalp.
5. Wait 4 minutes for the peptide to penetrate the hair fibre — do not rinse.
6. Style as usual. Use after every wash for the first 4-6 washes for noticeable results, then maintenance every few washes.

Specifications

• Brand: K18
• Product: Leave-In Molecular Repair Hair Mask
• Format: 15ml mini
• Use: Leave-in, after every wash for first 4-6 washes
• Vegan and cruelty-free: Yes (per brand)