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full-size leave-in molecular repair hair mask

4-minute leave-in treatment to reverse hair damage
Rated 4.6 out of 5
Based on 7067 reviews

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.

11+ billion TikTok views 🔥 

*Disclaimers

Repairs Damage Caused By

  • Bleach + Color Bleach + Color
  • Heat Heat
  • Chemical Services Chemical Services
OR
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more to know

  • 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

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

how to use

  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

dos and don'ts

  • 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

ingredients

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.

11+ billion TikTok views 🔥 

*Disclaimers
Image Comparison Drag Handle
see molecular repair in action
The K18 leave-in molecular repair hair mask delivers lasting + progressive results, for healthier hair with each use.

the experts know

Groundbreaking PRO stylists, scientists + beauty experts have unlocked new levels of expression with K18 molecular repair.

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 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.

what is the k18peptide™?

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

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 K18PEPTIDE™ 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.
reviews
average rating 4.6 out of 5
Based on 7067 reviews
  • 5 Stars
    5768 Reviews
  • 4 Stars
    667 Reviews
  • 3 Stars
    291 Reviews
  • 2 Stars
    136 Reviews
  • 1 Star
    205 Reviews
92% of reviewers would recommend this product to a friend
Customer photos and videos
7067 Reviews
Reviewed by Chandel B.
Verified Buyer
I recommend this product
Age
25 - 34
Hair Concern
  • Frizz
  • Fragile/brittle hair
  • Split-Ends
  • Dryness
Hair Type
  • Curly/Coily
  • Fine/Thin
My Results
  • Less Frizz
  • Visible Difference
  • Smoother Hair
  • Less Breakage
  • Defined Curl/Wave Pattern
Rated 5 out of 5
Review posted

Simply Amazing!

Makes my curly hair sooo much more manageable and healthy!

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Reviewed by Neda P.
Verified Buyer
I recommend this product
Age
25 - 34
Hair Concern
  • Frizz
  • Fragile/brittle hair
  • Dryness
  • Split-Ends
Hair Type
  • Curly/Coily
My Results
  • Bouncy Hair
  • Visible Difference
Rated 5 out of 5
Review posted

Amazing

Love this product helps a lot with my curly hair. Reduces frizz too

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Reviewed by Heather D.
Verified Buyer
I recommend this product
Age
35 - 44
Hair Concern
  • Heat damage
  • Dryness
  • Split-Ends
  • Fragile/brittle hair
Hair Type
  • Fine/Thin
My Results
  • Visible Difference
  • Smoother Hair
  • Soft Touchable Hair
  • Less Frizz
Rated 5 out of 5
Review posted

I like it 👌🏼

It's makes my hair appear more healthy so far

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K18Hair

❤️! We appreciate your review Heather!

Reviewed by AuroraBoobie A.
Verified Reviewer
I recommend this product
Age
55 - 64
Rated 5 out of 5
Review posted

Actually Works

My sister is a stylist & did this treatment on my hair. I'm so satisfied with the results. It actually does what it says it'll do. I have thick naturally curly hair & always need conditioning after shampoo products in my hair resulting in unwanted build up. After using K18 Biomimetic Hairscience Leave-In Molecular Repair Hair Mask, I don't need to!

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K18Hair

We appreciate your review! Love your hair!

Reviewed by Rosi G.
Verified Buyer
I recommend this product
Age
55 - 64
Hair Concern
  • Chemical damage
  • Frizz
  • Fragile/brittle hair
  • Dryness
Hair Type
  • Fine/Thin
  • Straight/Wavy
My Results
  • Less Frizz
  • Bouncy Hair
  • Visible Difference
  • Stronger Hair
  • Less Breakage
Rated 5 out of 5
Review posted

Magic!

My hair gets frizzy with humidity, I had tried all types of products before. K-18 is a miracle. I have recommended it to all my friends and they love it as much as I do,

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K18Hair

We appreciate your referral Rosi! Thank you for your review!

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