K18 Leave-In Molecular Hair Mask, Repairs Dry or Damaged Hair, Reverse Hair Damage from Bleach, Color, Chemical Services & Heat

K18 Leave-In Molecular Hair Mask, Repairs Dry or Damaged Hair, Reverse Hair Damage from Bleach, Color, Chemical Services & Heat

 8,423 Reviews
$69.99
$69.99
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Repairs Damage Caused By

Heat

Bleach + Color

Chemical Services

A leave-in treatment mask that works on the molecular level to reverse hair damage in just 4 minutes. The K18 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.

BUNDLE & SAVE

This is by far THE BEST leave in mask I have ever used, I love the long lasting scent it leaves, but the most important part I accidentally over processed my roots and other parts of my hair I HAD to save my hair and this product surely did my hair felt amazing after just one use but now just 3 uses later im obsessed my hair is soooo soft, silky smooth and feels brand new i cannot thank this company enough for saving my hair.

Hope L.
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Hair Type

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.

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More To Know

K18PEPTlDETM is a biotech-developed peptide that mimics hair'sstructure to reverse damage by reconnecting polypeptide chains anddisulfide bonds broken during bleaching, color and chemical services+ heat.

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Key Benefits

Reverses damage in 4 minutes* to restore strength, softness.smoothness + bounce
lmmediate + progressive results
Limited-edition scent

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key benefits

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 K18PEPTIDETM works on a molecular level (where all hair is the same), this product is effective on all hair types.

Limited Edition Fragrance - 50ml, Benefits as follows:

  • (Limited-edition scen Reverses damage in 4 minutes to restore strength, softness, smoothness + bounce
  • Immediate + progressive results
  • Limited-edition scent )

Core Technology and Ingredients

  • Core Active Ingredient: K18PEPTIDE™

    K18PEPTIDE™ is a biotechnology-developed peptide that mimics the structure of hair, repairing damaged hair by reconnecting peptide chains and disulfide bonds broken by bleaching, dyeing, and chemical heat treatment. It reconnects peptide chains (thus repairing disulfide bonds), providing comprehensive and lasting damage repair.

  • Auxiliary Ingredients: Protein-based ingredients

    Hydrolyzed wheat protein and hydrolyzed wheat starch have been added (see the China Daily science article: "Small molecule proteins penetrate the hair core without heating"). These small molecule proteins can fill the gaps in the hair core, restoring the hair's strength and elasticity.

  • pH Optimization: Formula pH Value

    The formula's pH value is controlled between 5.0 and 6.0, close to the hair's natural pH. This helps reduce cuticle swelling, maintains the "highly elastic state" of hair proteins, makes hair smooth, reduces frizz and split ends, improves hair quality, and thus reduces the risk of hair breakage during subsequent combing.

    How to use leave-in repair hair mask

    full-size leave-in molecular repair hair mask how to use

    1. Shampoo, do not condition. Towel-dry thoroughly.

    2. Apply 1-3 pumps of K18 leave-in molecularrepair hair maskbased onyour length and density, starting at the ends and working up towardsthe roots.

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


    4. Comb, add product + style as usual. Use for 4-6 washes post-salonservice,then as needed.

    Limited-Edition scent-50 mL how to use

    In the shower:
    Shampoo, don't condition.

    Out of the shower:
    Gently towel dry hair until damp.

    Apply one mL/one dime-sized amount of K18 Mask.

    Only add more as needed, Average use is two mL/two dime-sizeamounts (this is a highly concentrated formula, so you'll need muchless than traditional masks).
    Work evenly into hair from ends to roots.

    Wait four minutes for the K18PEPTlDErm to reach the innermost layersof hair
    Don't rinse out.

    Style as usual after the four minutes is up (fine to add heat protectantor styling product now).

    Use for the first four to six washes, then swap to maintenance modeand use as needed.

    Fragrance Notes on Limited Edition Fragrances

    • Top notes

      Cooling Bergamot + Black Pepper

    • Mid notes

      Dewy Freesia, Water Lily + Rose Absolute

    • Base notes

      Salted Musk, Wet Stones + Papyrus

      Soft, strong, bouncy hair for everyone

      • "Finally decided to take good care of my hair! It was so dry, frizzy, and had so many split ends, I really should have cut it sooner! This time I got a new length, and also got highlights and a touch-up. My stylist used this hair mask on me immediately after the perm and color, and I absolutely loved how it felt on my hair...I love this hair mask so much!"
        -Christina Marie P.

      • "Finally decided to take good care of my hair! It was so dry, frizzy, and had so many split ends, I really should have cut it sooner! This time I got a new length, and also got highlights and a touch-up. My stylist used this hair mask on me immediately after the perm and color, and I absolutely loved how it felt on my hair...I love this hair mask so much!"
        -Ashley P.

      • "Its texture and the shine it gives to the hair are simply perfect! When applied to the hair, it's neither sticky nor heavy. It absorbs quickly without leaving any stickiness. You can feel the incredible smoothness when you gently comb your hair with your fingers. Even the ends of your hair, which are usually prone to tangling, become soft and bouncy."

        -Sandra M.

      • "It made my hair incredibly soft and light, I love it! I've tried so many hair care products before, and they were either not moisturizing enough, leaving my hair dry and frizzy, or too heavy and oily, making my hair flat and lifeless against my scalp. But this one is completely different. Not only does it not make my hair flat, but it also keeps every strand of hair bouncy and light, maintaining a perfect style all day long. I highly recommend this product!"

        - Olga S.

      • "My hair used to be very dry, frizzy, split, and rough because I often dyed and permed it. It would break easily when I combed it, and even a simple ponytail felt dry, fragile, and lacked elasticity. At first, I tried this hair mask with a try-it-and-see attitude, but I didn't expect the effect to be so good. I have used it four times now, and every time I wash my hair, I can feel that it is gradually improving and becoming healthier."

        -Anastasiia T.

      • "My hair became frizzy due to heat damage, dyeing, and perming. Tangling, pulling, and split ends were common occurrences when combing, making hair care time-consuming and frustrating. Until I encountered this product, it completely changed my hair care predicament. The previously unruly curls became smooth and manageable, and split ends were visibly reduced. Now it has become an indispensable part of my daily life."

        - Siria A.

        Dos and don'ts

        Things to note

        ✔ 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.

        X DON'T use conditioner before applying K18 Mask (you can apply after the 4 min but most find they don’t need it).

        X DON'T rinse it out.

        The science behind K18

        Our story

        K18 is a biology-first haircare brand, powered by biotech. Using the power of nature andhuman biology, K18 unlocks new solutions to the biggest challenges in haircare - allwhile delivering a healthy canvas for hair expression. K18 creates purposeful productsthat are simple, effective, and biocompatible.

        Our story began with a decade of complex research into the bioscience of hair, resulting in our patented molecular repair peptide. Through this research and the application of synthetic biology, we are able to do more with less, simplifying formulations and routines to support hair health and expression at home and in the salon.

        Meet our proprietary biotechnology:

        K18PEPTIDE™

        K18PEPTIDE™ repairs hair at a molecular level across multiple types of bonds including polypeptide chains and disulfide bonds to reverse damage from bleach, color, chemical services, and heat*. Developed through biotechnology, the K18PEPTIDE™ is optimized for human biology and uniquely matches and clicks into hair’s keratin structure, reconnecting damage sites at the molecular level, K18PEPTIDE™ delivers durable repair for all hair types, restoring strength and elasticity.

        This peptide was designed in accordance with our less-is-more formulation philosophy to simplify and minimize steps in hair routines. This biomimetic molecule laid the foundation for our biology-first approach to haircare and works in just four minutes, with no extra steps, and with results shown from the very first application. For salon use, find it in the K18REPAIR™ service (K18 professional molecular repair hair mask and PRO molecular repair hair mist), and for home use, find it in the molecular repair hair mask and molecular repair hair oil.

        ODORBIND™

        ODORBIND™ revolutionizes what’s possible when targeting and eliminating odors. Using biotechnology and synthetic biology, K18 bioscientists utilized DNA databases to find and mimic the strongest olfactory systems (our sense of smell) found in nature. ODORBIND™ harnesses that understanding of nature and biology to uniquely recognize, trap, and eliminate malodors, rendering them undetectable and releasing a subtle fragrance in their place. This smart-release molecule is vegan, cruelty-free, and certified Kosher and Halal. Find it in AirWash™, the reinvention of dry shampoo.

        Resilicore™

        Patented resilicore™ heat-shielding technology protects from heat deeper than ever before. Unlike traditional heat protectants that only coat hair’s cuticle, the size + molecular makeup of resilicore™ allows it to penetrate into hair's core to defend against heat from the cuticle to the cortex—as deep as heat damage goes. Inspired by proteins in nature that can withstand extreme temperatures, this protective shield fortifies hair from within for maximum protection against color fade, dry feeling, dullness, and breakage. This heat-shielding tech is inspired by nature, and recreated in the lab to be vegan, sustainable + and cruelty-free. Find it in HeatBounce, the future of heat protection.

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        Got questions?

        Get started here.

        How does the k18 mask work?

        The K18 mask works as a treatment to reverse damage in 4 minutes. It’s powered by our biomimetic K18PEPTIDETM 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.

        What is the k18peptiderm?

        K18PEPTIDETM 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.

        Why skip conditioner?

        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.

        I noticed there's alcohol in the formula, isn't that bad for you?

        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 K18PEPTIDETM can penetrate the innermost layer of hair, reaching the broken polypeptide chains (keratin chains).

        When should i expect to see results?

        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.

        Do I need to rinse this product after use?

        No rinsing required; this is a leave-in hair mask. This is the key to its product design and the core of its revolutionary repair effects.
        Traditional hair masks primarily work on the hair surface, filling the cuticles and increasing smoothness; these ingredients can be washed away with water. K18's core ingredient, K18Peptide™, is a bioactive peptide that aims to penetrate the hair shaft and repair broken disulfide bonds (structural damage within the hair).
        It needs time to penetrate; the product needs to remain on the hair to continue working. If it is rinsed off after only 4 minutes, its repairing effect will be greatly reduced, and it will fail to achieve its mission of "molecular repair".