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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 6659 reviews

A leave-in treatment mask for all hair types that clinically reverses damage in 4 minutes. The patented peptide technology works to repair damage from bleach, color, chemical services & heat – restoring strength, softness, smoothness, and bounce to hair.

11+ billion TikTok views 🔥 

Repairs Damage Caused By

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

The K18PEPTIDE™ works at the innermost layer of hair, reconnecting polypeptide chains and disulfide bonds broken during bleaching, chemical services, and through heat damage.


By addressing these damage sites at the innermost layer of hair, core strength and elasticity are renewed for strong, smooth, bouncy hair—even after the most extreme damage done in the salon or at home.

key benefits

  • Powered by the patented K18PEPTIDE™, engineered over 10 years in a biotech lab to work on the molecular level to rebuild hair from the inside out in just 4 minutes.
  • Because the K18PEPTIDE™ works at the molecular level, it works on every single hair type
  • Clinically proven to reverse hair damage from: Bleach + Color, Chemical Services, Heat
  • Restores strength, softness, smoothness, and bounce
  • Immediate + progressive results
  • Vegan, color-safe, cruelty-free

how to use

  1. Shampoo, do not condition.
  2. Towel-dry thoroughly.
  3. Begin with 1 pump of K18 mask and add more as needed depending on length, thickness, and condition. Work evenly into hair from ends to roots, one pump at a time, maximum dosage is 3 pumps.
  4. Let sit for 4 minutes. Do not rinse out.
  5. Then comb + style as usual (fine to add heat protectant or styling product now).
  6. Use for the first 4-6 washes, then as needed

how to optimize K18

  • 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.

pairs well with
PEPTIDE PREP™ detox shampoo 8.5ozPEPTIDE PREP™ detox shampoo 8.5oz

PEPTIDE PREP™ detox shampoo

Rated 4.6 out of 5
Based on 64 reviews
Color-safe, non-stripping clarifying shampoo with the K18PEPTIDE™ View PEPTIDE PREP™ detox shampoo 8.5oz product
PEPTIDE PREP™ pH maintenance shampoo 8.5ozPEPTIDE PREP™ pH maintenance shampoo 8.5oz

PEPTIDE PREP™ pH maintenance shampoo

Rated 4.4 out of 5
Based on 85 reviews
Color-safe, pH-optimized cleansing shampoo formulated with K18PEPTIDE™ View PEPTIDE PREP™ pH maintenance shampoo 8.5oz product

Description

A leave-in treatment mask for all hair types that clinically reverses damage in 4 minutes. The patented peptide technology works to repair damage from bleach, color, chemical services & heat – restoring strength, softness, smoothness, and bounce to hair.

11+ billion TikTok views 🔥 

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?

K18 works as a treatment to reverse damage in 4 minutes. How it works is a lot like makeup vs. skincare. Concealers (i.e. most hair products) temporarily cover up a problem. K18 works like retinol, highly concentrated, working on a deeper level to renew that base health so you can wear less concealer in the future. Pretty cool right?

what is the k18peptide™?

Our biomimetic peptide mimics hair’s natural structure to seamlessly fit in and reconnect broken keratin chains responsible for hairs core strength and elasticity. As a result of this reconnection it also addresses cleaved disulfide bonds for connection along the Y-axis of hair AND the x-axis or width of hair.

why skip conditioner?

Conditioner leaves a film on the cuticle that blocks our peptide from penetrating into the innermost layers 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 ingredients needed to get the peptide where it needs to go. Our unique blend of 3 alcohols functions to open up the hair cuticle so the K18PEPTIDE™ can penetrate the innermost layer of hair, reaching the broken polypeptide chains (keratin chains). Here the alcohol serves as an agent to optimize the hair environment for K18 mask to work on a deeper level and give you the best results.

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 results may vary depending on your hair type + level of damage.
reviews
average rating 4.6 out of 5
Based on 6659 reviews
  • 5 Stars
    5407 Reviews
  • 4 Stars
    635 Reviews
  • 3 Stars
    280 Reviews
  • 2 Stars
    134 Reviews
  • 1 Star
    203 Reviews
92% of reviewers would recommend this product to a friend
6659 Reviews
Reviewed by Anne C.
Verified Buyer
I recommend this product
Age
65+
Hair Concern
  • Color-care
  • Heat damage
  • Chemical damage
  • Frizz
Hair Type
  • Straight/Wavy
  • Grey Hair
My Results
  • Smoother Hair
  • Shinier Hair
  • Less Frizz
  • Visible Difference
Rated 5 out of 5
Review posted

IF YOU’RE TIRED OF FRIZZ

If you’re tire of frizz this is the product for you!!! Apply this liberally on clean , wet towel dried hair, and blow dry and frizz is no more. I love it and have been using for two years.

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Reviewed by Ingrid B.
I recommend this product
Age
65+
Hair Concern
  • Fragile/brittle hair
  • Dryness
  • Split-Ends
  • Heat damage
  • Chemical damage
Hair Type
  • Fine/Thin
My Results
  • Visible Difference
  • Smoother Hair
  • Soft Touchable Hair
  • Shinier Hair
  • Less Breakage
Rated 5 out of 5
Review posted

It works!

I am a new user.My hair is in really bad shape,very thin and dry.So far,I have used it twice and I already see and feel a difference.My hair looks and feels fuller.It is soft and looks healthier.I still got a ways to go,but I will definitely continue until my hair is completely healed.

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K18Hair

Thank you Ingrid for your review!!

Reviewed by Maryann P.
Verified Buyer
I recommend this product
Age
55 - 64
Hair Concern
  • Chemical damage
  • Frizz
  • Fragile/brittle hair
  • Dryness
  • Heat damage
Hair Type
  • Fine/Thin
  • Straight/Wavy
My Results
  • Soft Touchable Hair
  • Bouncy Hair
  • Less Frizz
Rated 5 out of 5
Review posted

Repair

Well I've only used it once since I could only afford the mini. The result I had with it was good it seemed to condition without heavy weigh down. I plan on using all of the contents of the mini with hopes of seeing some good results on my hair.

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K18Hair

Thank you Maryann for your review!

Reviewed by Jennifer S.
Verified Buyer
I recommend this product
Age
45 - 54
Hair Concern
  • Heat damage
  • Frizz
  • Dryness
Hair Type
  • Medium Density
  • Straight/Wavy
My Results
  • Less Frizz
  • Visible Difference
  • Smoother Hair
  • Shinier Hair
Rated 5 out of 5
Review posted

Dream hair repair!

I've been using this product for several months and I've noticed my hair looks so healthy! I'm 51 but my hair no longer looks dry and frizzy. Love, love, love it!

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K18Hair

Thank you for your review Jennifer!!

Reviewed by Michelle O.
Verified Buyer
I recommend this product
Age
35 - 44
Hair Concern
  • Chemical damage
Hair Type
  • Fine/Thin
My Results
  • Visible Difference
Rated 5 out of 5
Review posted

Love, love, love!

It's a miracle, I saw the difference on the first time. Really worthy!

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K18Hair

Thank you Michelle for your review!

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