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
- Wash the hair with shampoo as usual; do not condition.
- Towel-dry the hair until just damp.
- Dispense a small amount onto the palms — typically a 5p-sized amount for shoulder-length hair.
- Apply evenly through the lengths and ends, avoiding the scalp.
- Wait 4 minutes for the peptide to penetrate the hair fibre — do not rinse.
- 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)
Related Products
