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best seller
4.7
Rated 4.7 out of 5 stars
8,073 Reviews

full-size leave-in molecular repair hair mask

4-minute leave-in treatment to reverse hair damage
OR

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
  • 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.

  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.
  • 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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Color-safe, non-stripping clarifying shampoo with the K18PEPTIDE™

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.
Straight bleached hair after using K18 mask.
Straight bleached hair before using K18 mask.

healthier hair with every use

Reverse damage in 4 minutes with our breakthrough K18 molecular repair technology.
the K18 difference
Feel what’s possible with fewer steps, less waste + less time.
efficacy
patented K18PEPTIDE™ powers deeper + lasting repair.
simplicity
fewer steps for a streamlined routine.
speed
results in one 4-minute use.
how molecular repair compares
how K18 works

Traveling into the innermost layers of hair, our K18PEPTIDE™ renews strength along the width AND length of hair for lasting strength where it matters.

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 8,073 reviews
8,073 reviews
  • Amanda W.
    Verified Buyer
    Reviewing
    Mini Leave-In Molecular Repair Hair Mask 15 mL
    I recommend this product
    Age 45 - 54
    Hair Concern Chemical damage, Heat damage, Color-care, Fragile/brittle hair, Split-Ends
    Hair Type Medium Density, Fine/Thin
    My Results Less Frizz, Visible Difference, Stronger Hair
    Rated 5 out of 5 stars
    21 hours ago
    Wonderful product!

    Great product, does what it says and more! I love using this intermittently after hair color.

  • Brooke Z.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50mL
    I recommend this product
    Age 25 - 34
    Hair Concern Heat damage, Chemical damage, Frizz, Split-Ends
    Hair Type Medium Density
    My Results Less Breakage
    Rated 5 out of 5 stars
    Yesterday
    Love the leave in conditioner!

    Product is great!

    K Profile picture for K18Hair
    K18Hair
    Yesterday

    Thank you for your review!

  • Pamela P.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50mL
    I recommend this product
    Age 35 - 44
    Hair Concern Chemical damage, Heat damage, Fragile/brittle hair, Color-care, Split-Ends
    Hair Type Medium Density
    My Results Less Breakage, Stronger Hair, Visible Difference, Cleaner, fresher hair, Smoother Hair
    Rated 5 out of 5 stars
    4 days ago
    Really works

    There’s so many products that say that will help with chemical damaged hair, my hair is blonde and to be blonde it can really damage your hair. I noticed that my hear is getting healthy less breakage softer. Don’t forget to use a heat protector after.

    K Profile picture for K18Hair
    K18Hair
    2 days ago

    Thank you for your review!

  • Mariah H.
    Verified Buyer
    Reviewing
    Leave-In Molecular Repair Hair Mask 15 mL (WHOLESALE)
    I recommend this product
    Age 18 - 24
    Client Hair Concerns Chemical Damage, Dryness, Frizz
    Client Hair Types Medium Density
    Client Results Less Breakage, Defined Curl/Wave Pattern, Soft Touchable Hair, Stronger hair, Bouncy Hair
    Rated 4 out of 5 stars
    6 days ago
    Definitely helps!

    My hair was chemically damaged and a large piece broke off. I’ve used this twice since then (so far) and it’s helped me not lose a lot more hair, and I’ve noticed less tangles. My hair has been so much softer and my curls are happier too. I’m definitely going to keep using this product. I only gave 4 stars because I do still have more breakage happening and I had to cut off quite a bit

    K Profile picture for K18Hair
    K18Hair
    6 days ago

    K18 is a progressive treatment. It will get better with each application!

  • Jennifer M.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50mL
    I recommend this product
    Age 45 - 54
    Hair Concern Chemical damage, Frizz, Fragile/brittle hair, Dryness
    Hair Type Thick/Coarse, Grey Hair, Curly/Coily
    My Results Less Frizz, Visible Difference, Less Breakage, Stronger Hair, Defined Curl/Wave Pattern
    Rated 5 out of 5 stars
    1 week ago
    LOVE THIS

    I can’t truly express how much I absolutely love this product!! My hair can actually air dry after using it and it’s not frizzy!! I no longer need all sorts of products to make it not frizzy! One and done!!!

    K Profile picture for K18Hair
    K18Hair
    6 days ago

    Thank you Jennifer! We love your review!

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