Free Standard Shipping on $50+ Orders
free returns. buy with confidence
best seller

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 7350 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.

20+ billion TikTok views 🔥 

*Disclaimers

Repairs Damage Caused By

  • Bleach + Color
  • Heat
  • Chemical Services
OR
FREE SHIPPING ON $50+ ORDERS. FREE RETURNS
Every purchase supports K18 x Plastic Bank efforts to radically simplify waste.
In 2022 we stopped 147 Metric tons of plastic
=
7.3M+ single-use plastic bottles from reaching the ocean

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.

pairs well with

K18 molecular repair hair oil

Rated 4.7 out of 5
Based on 360 reviews
Weightless oil that strengthens, repairs damage + reduces frizz View Molecular Repair Hair Oil product

PEPTIDE PREP™ detox shampoo

Rated 4.8 out of 5
Based on 223 reviews
Color-safe, non-stripping clarifying shampoo with the K18PEPTIDE™ View PEPTIDE PREP™ detox shampoo 8.5oz product

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.

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.
Image Comparison Drag Handle
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.

reviews
average rating 4.6 out of 5
Based on 7350 reviews
  • 5 Stars
    6009 Reviews
  • 4 Stars
    678 Reviews
  • 3 Stars
    301 Reviews
  • 2 Stars
    144 Reviews
  • 1 Star
    218 Reviews
92% of reviewers would recommend this product to a friend
7350 Reviews
Reviewed by Mandy P.
Verified Buyer
I recommend this product
Age
45 - 54
Client Hair Concerns
  • Chemical Damage
  • Fragile/Brittle Hair
  • Heat Damage
  • Color Care
  • Dryness
Client Hair Types
  • Medium Density
  • Straight/Wavy
Client Results
  • Visible Difference
  • Stronger hair
Rated 5 out of 5
Review posted

Mlp00

Damaged highlights looked much healthier after just 1 use

Loading...
Was this helpful?

K18Hair

Thank you for your review, Mandy!

Reviewed by Veronica
I recommend this product
Rated 5 out of 5
Review posted

5 Stars

Love this product! Since the first application I was able to see a huge difference in my hair.

Loading...
Was this helpful?
Reviewed by Andrea H.
Verified Buyer
I recommend this product
Age
35 - 44
Hair Concern
  • Color-care
  • Frizz
  • Dryness
Hair Type
  • Fine/Thin
My Results
  • Less Frizz
  • Stronger Hair
  • Smoother Hair
  • Shinier Hair
  • Visible Difference
Rated 5 out of 5
Review posted

Best hair mask EVER!

This hair mask makes me love my hair. Helps frizz and looks so healthy ❤️

Loading...
Was this helpful?

K18Hair

Thank you for your review, Andrea!

Reviewed by Elizabeth
I recommend this product
Rated 4 out of 5
Review posted

4 Stars

Living this product. my hair feels nd looks great.

Loading...
Was this helpful?
Reviewed by Doreen G.
Verified Reviewer
I recommend this product
Age
65+
Hair Concern
  • Chemical damage
  • Heat damage
  • Fragile/brittle hair
  • Frizz
  • Dryness
Hair Type
  • Fine/Thin
My Results
  • Less Frizz
  • Soft Touchable Hair
  • Smoother Hair
  • Shinier Hair
Rated 5 out of 5
Review posted

Amazing product

I have alopecia and my hair is very brittle and dry well what there is of it and I only bought the small tube to try. I washed it yesterday and can’t believe the difference after one wash it’s so soft and shiny absolutely brilliant product

Loading...
Was this helpful?

K18Hair

We appreciate your 5 star review! Thank you Doreen!

Pro Distribution Partners

Paramount Beauty Supply
USA
Salon Services Pro
USA
Salon Service Group
USA
Salonwax Pro
USA
Premier Beauty Supply
USA
Launching Soon
Ozdare - Australia
AU
 
Launching Soon
American Crew Ltd. - New Zealand
NZ
 
Launching Soon
PlayGround - Hong Kong
HK
 
Launching Soon
Session Map - Sweden
SE
 
Launching Soon
Cyprus
CY
 
Launching Soon
Belgium
BE
 
Coming Early 2021
Canada
CA
 
Coming Early 2021
Czech Republic
CZ
 
Coming Early 2021
Finland
FI
 
Coming Early 2021
France
FR
 
Coming Early 2021
Germany
DE
 
Coming Early 2021
Ireland
IR
 
Coming Early 2021
Italy
IT
 
Coming Early 2021
Netherlands
NL
 
Coming Early 2021
Norway
NO
 
Coming Early 2021
Singapore
SG
 
Coming Early 2021
Taiwan
TW
 
Coming Early 2021
UK
UK
 
Coming Early 2021
thank you for visiting!

You are now being redirected to an official partner website for this region where you can shop K18 Hair.

Changed your mind? Go back.

00:00
Blackfire Tracking
subscribe + save 15%
healthy hair on your schedule
Pick your K18 + how often you want to replen.
We’ll send you a heads up before every delivery.
You’re in charge. Change the way you pay, skip a shipment, or cancel anytime.