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tilebestseller | color:black
4.7
Rated 4.7 out of 5 stars
4,496 Reviews

full-size leave-in molecular repair hair mask

4-minute leave-in treatment to reverse hair damage
COMING SOON

Description

A leave-in treatment mask that works on the molecular level to reverse hair damage in just 4 minutes. The K18PEPTIDE™ is clinically proven to repair damage from bleach + color, chemical services and heat* – with immediate and lasting results to restore strength, softness, smoothness and bounce to hair.

20+ billion TikTok views 🔥

*Disclaimers

Repairs Damage Caused By

  • Bleach + Color
  • Heat
  • Chemical Services
  1. Shampoo, do not condition. Towel-dry thoroughly.
  2. Apply 1-3 pumps of K18 leave-in molecular repair hair mask based on your length and density, starting at the ends and working up towards the roots.
  3. Let sit for 4 minutes. Do not rinse out.
  4. Comb, add product + style as usual. Use for 4-6 washes post-salon service, then as needed.
  • K18PEPTIDE™ is a biotech-developed peptide that mimics hair's structure to reverse damage by reconnecting polypeptide chains and disulfide bonds broken during bleaching, color and chemical services + heat*.

  • pH-optimized (5.0-6.0) to help minimize cuticle swelling + put hair proteins in their most resilient state.

  • Cream format enables easy, lightweight application across all hair types, with detangling and softening benefits.

  • Vegan, color-safe, cruelty-free.

Takes damage repair further – reconnects both polypeptide chains (and as a result, also reconnects disulfide bonds) for strength along the length + width of the hair - offering comprehensive, lasting damage repair.

Restores hair from even extreme damage - by working at the innermost layer of the hair, core strength and elasticity are renewed for strong, smooth, bouncy hair.

Delivers immediate and lasting results – hair is repaired from the first use and lasts past your next wash, for ongoing reparative benefits.

Simplified repair - convenient, leave-in formula works in just 4 minutes, with no extra rinse required.

Works on all hair types – because K18PEPTIDE™ works on a molecular level (where all hair is the same), this product is effective on all hair types.

  • DO clarify before K18 if you’re a heavy product user (demineralize for mineral + metal buildup).
  • DO apply on clean, damp hair.
  • DO wait the full 4 minutes before combing or styling.
  • DO add whatever styling products you love after the 4 minutes.
  • DO use for 4-6 shampoos consecutively for progressive results.
  • DON'T use conditioner before applying K18 Mask (you can apply after the 4 min but most find they don’t need it).
  • DON'T overdo it—less is more.
  • DON'T rinse it out.

Water (Aqua) (Eau), Alcohol Denat., Propylene Glycol, Cetearyl Alcohol, Dicaprylyl Ether, Cetyl Esters, Behentrimonium Chloride, Polysorbate 20,sh-Oligopeptide-78 (K18PEPTIDE™), Hydrolyzed Wheat Protein, Hydrolyzed Wheat Starch, Isopropyl Alcohol, Tocopherol, Phenoxyethanol, Potassium Sorbate, Citric Acid, Fragrance (Parfum), Geraniol, Linalool, Hexyl Cinnamal, Benzyl Alcohol.

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Description

A leave-in treatment mask that works on the molecular level to reverse hair damage in just 4 minutes. The K18PEPTIDE™ is clinically proven to repair damage from bleach + color, chemical services and heat* – with immediate and lasting results to restore strength, softness, smoothness and bounce to hair.

20+ billion TikTok views 🔥

*Disclaimers

got questions?
Get started here.
The K18 mask works as a treatment to reverse damage in 4 minutes. It’s powered by our biomimetic K18PEPTIDE™ to seamlessly fit in and reconnect broken polypeptide chains at the molecular level. As a result, disulfide bonds are also reconnected for reinforced strength along the length + width of hair—offering comprehensive, lasting, and progressive repair.
K18PEPTIDE™ is a biotech-developed peptide that mimics hair’s structure to reverse damage by reconnecting polypeptide chains and disulfide bonds broken during damage from bleach + color, chemical services, and heat*
*Disclaimers
Conditioner leaves a film that blocks our peptide from penetrating effectively. Once the 4-minute wait time is up, feel free to use a conditioner, a leave-in, or any type of product.
We like to keep our formulas minimal, only using the exact amount of ingredients needed to get the peptide where it needs to go. Here the alcohol serves as an agent to optimize the hair environment for the K18 mask to work on a deeper level. Our unique blend of 3 alcohols functions to open the hair cuticle so the K18PEPTIDE™ can penetrate the innermost layer of hair, reaching the broken polypeptide chains (keratin chains).
Most see results after 2-3 uses. The more damaged the hair, the more dramatic the results so it may vary depending on your hair type and level of damage.
powered by K18PEPTIDE™

Biomimetic peptide clicks into hair’s keratin structure—the source of core strength—for soft, shiny, bouncy results that won’t wash away.

how to use molecular repair mask
1. Shampoo, do not condition. Towel-dry thoroughly.

2. Apply 1-3 pumps based on your length and density, starting at the ends and working up towards the roots.

3. Let sit for 4 minutes. Do not rinse out.

4. Comb, add styling product + style as usual. Use for 4-6 washes, then as needed.
feel what's possible with K18
See how K18 unlocks our community's expression
4.7
Rated 4.7 out of 5 stars
Based on 4,496 reviews
4,496 reviews
  • Esther Y.
    Verified Buyer
    I recommend this product
    Age 35 - 44
    Hair Concern Chemical damage, Fragile/brittle hair, Color-care, Dryness
    Rated 5 out of 5 stars
    1 week ago
    Hair repair

    My bleached hair was so brittle and dry. K18 hair mask saved it after 2-3 uses

    KU Profile picture for K18Hair UK
    K18Hair UK
    3 days ago

    It's amazing how quickly it can work its magic on damaged hair. Thanks for the amazing 5-star review!

  • Hailey B.
    Verified Buyer
    I recommend this product
    Age 25 - 34
    Hair Concern Heat damage, Color-care, Split-Ends, Dryness
    Hair Type Medium Density
    My Results Smoother Hair, Soft Touchable Hair, Shinier Hair, Less Breakage, Visible Difference
    Rated 5 out of 5 stars
    2 weeks ago
    I love this stuff!

    I have been using this for years and will forever keep using it. I recommend to everyone!

    KU Profile picture for K18Hair UK
    K18Hair UK
    2 weeks ago

    Your loyalty and recommendation to everyone means the world to us. Thanks for the amazing review!

  • Denise B.
    Verified Buyer
    I recommend this product
    Age 55 - 64
    Hair Concern Chemical damage, Frizz, Dryness, Extending time between washes
    Hair Type Grey Hair, Straight/Wavy, Medium Density
    My Results Less Frizz, Visible Difference, Stronger Hair, Smoother Hair, Shinier Hair
    Rated 5 out of 5 stars
    2 months ago
    Magic in a bottle

    This product has transformed my hair!

    Why did it take me 60 years to discover it??

    KU Profile picture for K18Hair UK
    K18Hair UK
    1 month ago

    Thank you so much for this amazing review, Denise! Your hair is beautiful! We love that you're experiencing the magic and appreciate you taking the time to share your wonderful experience!

  • Niav H.
    Verified Buyer
    I recommend this product
    Age 35 - 44
    Hair Concern Extending time between washes, Fragile/brittle hair, Color-care
    Hair Type Fine/Thin, Straight/Wavy
    My Results Soft Touchable Hair, Cleaner, fresher hair, Bouncy Hair, Visible Difference, Oil absorbed
    Rated 5 out of 5 stars
    3 months ago
    Love this product

    I have been loving using this product. It works as advertised. 4 pumps after shampooing only. My hair is in better shape after several weeks of using

    KU Profile picture for K18Hair UK
    K18Hair UK
    3 months ago

    We’re so happy K18 is bringing your hair back to life, thank you for trusting us with your strands!

  • Mallory
    Verified Reviewer
    I recommend this product
    Age 18 - 24
    Hair Concern Chemical damage, Frizz, Dryness, Fragile/brittle hair, Split-Ends
    Hair Type Medium Density, Straight/Wavy, Curly/Coily
    My Results Visible Difference, Bouncy Hair, Defined Curl/Wave Pattern, Stronger Hair, Soft Touchable Hair
    Rated 5 out of 5 stars
    3 months ago
    Has changed my curls for the better

    All my life I didn’t know how to look after my curly properly and growing up, I always thought i was just fluffy and wide. I never knew my hair was frizzy or knew how to look after it. I work in a chlorinate environment for the last year and a half and the chlorine was damaging my hair and curls. For about 8-9 months I’ve been wearing a big swimming cap to prevent any more chlorine from getting into my hair and it has helped but the damage was still there.

    No until about 3 months ago I discovered the K-18 bond repair treatment and technics and products to help with curly hair. I was a little bit hesitant to buy the K-18 mask but I needed something to help repair my hair.

    I’m very glad I have. Over the last 2 months I’ve been styling my hair like curly hair and added the K-18 repair mask into my routines and my hair has never looked or felt better. The photos are the before and after and my after photos show my definition within my curls and my hair is much stronger. This bond repair treatment has not only saved my hair from the damage from the chlorinated water but has brought my curls back to life. I never knew my hair could be this curly. This mask has been a true curl/hair saver and I will continue to use it in my routine. <3

    The photo when I’m in the blue shirt was me just over 2 months ago and the photos of me in the black shirt is me recently. I’m also showing how defined my curls have been in one of the photos, ignore the mess in the background as my bathroom is…

    KU Profile picture for K18Hair UK
    K18Hair UK
    3 months ago

    Wow! These are some amazing results! Thank you for trusting us with your beautiful hair!

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