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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 7062 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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Rated 4.8 out of 5
Based on 208 reviews
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PEPTIDE PREP™ detox shampoo

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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 7062 reviews
  • 5 Stars
    5763 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
7062 Reviews
Reviewed by Karen O'Connell M.
Verified Buyer
I recommend this product
Age
55 - 64
Hair Concern
  • Chemical damage
  • Fragile/brittle hair
Hair Type
  • Fine/Thin
  • Grey Hair
My Results
  • Less Frizz
  • Visible Difference
  • Less Breakage
Rated 5 out of 5
Review posted

Fried ends

This is a great product for repair and over processed hair. Suggested by my stylist-I use once a week and it is really working.

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K18Hair

Happy to hear you are getting noticeable results! Thank you for your review!

Reviewed by Lauren L.
Verified Buyer
I recommend this product
Age
35 - 44
Hair Concern
  • Split-Ends
  • Heat damage
  • Fragile/brittle hair
Hair Type
  • Fine/Thin
My Results
  • Stronger Hair
  • Smoother Hair
Rated 5 out of 5
Review posted

Game Changer!

I have been looking for a solution to my fine, thin blonde hair that tends to break and just is blah. I have used K18 5 times now and the difference is incredible! It has totally changed my hair for the better! It is soft, feels and looks stronger. It looks less stringy. I'm really hopeful that with continued use it will help me actually grow my hair. I was worried not using conditioner would make my hair super hard to comb out and leave it dry and tangly. It does not! I still spray my leave in conditioner after the 4 minutes are up and it combs out just fine. I will definitely be purchasing the larger size now that I've tried it and love it.

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K18Hair

Thank you for your review Lauren! 💛💪🏼

Reviewed by Diana B.
Verified Buyer
I recommend this product
Age
45 - 54
Hair Concern
  • Chemical damage
  • Heat damage
  • Color-care
  • Frizz
  • Fragile/brittle hair
Hair Type
  • Medium Density
  • Straight/Wavy
My Results
  • Less Breakage
Rated 5 out of 5
Review posted

K18 is the best

Love this stuff, it helps keep my ends healthy.

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K18Hair

Your the best! We appreciate your review Diana!

Reviewed by Emma E.
Verified Buyer
I recommend this product
Age
25 - 34
Hair Concern
  • Dryness
  • Split-Ends
Hair Type
  • Thick/Coarse
  • Curly/Coily
My Results
  • Stronger Hair
Rated 4 out of 5
Review posted

Great Product

My hair felt better after 2 weeks of using this.

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K18Hair

We appreciate your review Emma!

Reviewed by Linda C.
Verified Buyer
I recommend this product
Age
65+
Hair Concern
  • Fragile/brittle hair
  • Dryness
  • Split-Ends
  • Frizz
Hair Type
  • Medium Density
My Results
  • Bouncy Hair
  • Visible Difference
  • Stronger Hair
  • Less Breakage
  • Smoother Hair
Rated 5 out of 5
Review posted

I Love, love, love this product-Leave in Molecular Repair Hair Mask

All I can say is that this product has changed my overall hair health and I Look awesome!

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K18Hair

Thank you Linda for your review!

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