4.7

Rated 4.7 out of 5 stars

8,590 Reviews

leave-in molecular repair hair mask

Name: Leave-In Molecular Repair Hair Mask Deluxe Sample
Brand: K18Hair
SKU: K18-31001
Availability: InStock
Rating: 4.7 (8590 reviews)

4-minute leave-in treatment to reverse hair damage

Leave-In Molecular Repair Hair Mask Deluxe Sample $0.00

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

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.

Repairs Damage Caused By

Bleach + Color
Heat
Chemical Services

how to use

IN the shower

Shampoo, do not condition.

OUT of the shower

Towel dry thoroughly.
Begin with 1 pump of the K18 Mask and add more as needed depending on the length, thickness, and condition.
Work evenly into hair from ends to roots, one pump at a time.
Let sit for 4 minutes to activate.
Do NOT rinse out.
Style as usual.

more to know

creates hair like new

Traveling deeper into the inner layers of hair than traditional repair products, our revolutionary patented K18Peptide™ is just the right size and makeup to fit in and reconnect broken keratin chains, renewing hair with strength, softness, smoothness, and bounce. You can feel and see the difference with the first use.

Start by using K18 after the first 4-6 washes. Then switch to maintenance mode for a boost of renewed strength, softness, smoothness, and bounce when needed.

do's + don'ts

DO use a clarifying shampoo if you’re a heavy product or dry shampoo user to remove buildup and help our peptide penetrate and get where it needs to go.
DO wait the full 4 minutes before styling or applying other product
DO use every 4-6 shampoos consecutively to see and feel ongoing results

DON’T condition your hair before application (trust us, most won’t need it after K18, if you still need, add a leave-in after the 4-minute window is up post-application)
DON’T overuse, a little goes a long way.
DON’T rinse out. This is a leave-in, so you know, leave it in!

key benefits

Our K18Peptide™ is clinically proven to reverse damage in just 4 minutes.

Heals damage from bleach, color, chemical services, and heat
Restores strength, softness, smoothness, and bounce
Doesn’t wash away with shampoo, leaving lasting results
Vegan, color-safe, cruelty-free

up to 91% original strength*
up to 94% original elasticity*

* Results observed in a clinical study while using mist and mask as part of a bleaching treatment. Results may vary depending on hair type, quality and history.

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.

Description

what you can expect
by damage type

backed by science,
loved by stylists

Our community of stylists and colorists believe K18 is liberating hair—no matter the hair type or generation.

“K18 allows me to go everywhere I want to go with my color work and the end result is my guests get to be bright and shiny and healthy.”

– Christine Thompson, Director of Color at Spoke & Weal

got questions?

Get started here

How does K18 work?

When hair gets damaged, the polypeptide chains (keratin chains) that make up the inner structure of hair strands become weakened and break. For context, there are billions and billions of polypeptide chains (keratin chains) in a single strand of hair. When these are damaged, hair’s core structure responsible for elasticity and strength becomes compromised and as a result it loses its resiliency and shine—or the look and feel of healthy hair.

After spending a decade in the lab scanning and testing all amino acid sequences across the entire keratin genome that makes up human hair searching for a breakthrough, we discovered one unique sequence (a bioactive peptide) that brings damaged hair back to its original, youthful state. This is our K18Peptide™.

Traveling deeper into the inner layers of hair than traditional repair products, our revolutionary peptide is just the right size and makeup to fit in and reconnect those broken polypeptide chains (keratin chains). And because our peptide is a bit of an overachiever, as a result of this reconnection, any disturbed disulfide bonds are also re-conformed.

Our peptideemploys biomimetics to get the job done. To put it simply: Biomimetics is the practice of learning from and mimicking nature. Mimicking the natural structure of keratin building blocks (amino acid sequences), our K18 bioactive peptide is recognized as natural by the hair. It’s not washed away by water or shampoo like traditional bonding agents either, making K18 a genuine, lasting solution for damaged strands.

What is the K18Peptide™?

Our patented peptide is a unique sequence of amino acids that travels deep into hair’s core structure to fit in and reconnect broken polypeptide chains (keratin chains) responsible for hair strength and elasticity.

An Analogy: When building proteins, the order of the amino acids determines the kind of protein and its properties, much like the way letters are arranged to make meaningful words and sentences. In the same way the order and where each word sits in a sentence leads to its overall meaning, K18 is the magic word that fits right in, integrating itself with the keratin chains as the hair recognizes it as a natural building block.

Why should I skip conditioner?

K18 is most effective on clean, towel-dried hair. Conditioners use silicones and conditioning agents that form heavy coatings on hair , preventing our peptide from reaching the broken polypeptide chains deep inside hair’s inner layer.

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. Our unique blend of 3 alcohols function to open up the hair cuticle so the K18Peptide ™ can penetrate the inner most layer of hair, reaching the broken polypeptide chains (keratinchains). Here the alcohol serves as an agent to optimize the hair environment for K18 to work on a deeper level.

When should I expect to see results?

You will start to see stronger, softer, healthier hair after just one use.

Renews strength, softness, smoothness, and bounce

Curly
Coily
Straight

K18 strengthens hair’s core structure, restoring damaged curl patterns and leaving strands looking and feeling like new.

K18 reconnects broken keratin chains, restoring hairs elasticity and strength meaning coily hair can be renewed and brought back to its original springy, healthy shape.

K18 restores strength, softness, smoothness, and bounce so even the sleekest hair can feel like new.

4.7

Rated 4.7 out of 5 stars

Based on 8,590 reviews

Reviews Summary

Customers say this leave-in hair mask transforms their hair texture and manageability after just one use. Many reviews mention noticeable improvements in softness and reduced frizz. Users with curly, fine, and color-treated hair report positive results. The mask works well for various hair types, with many noting improved texture and easier styling. While some mention the product's high price point, most find a little goes a long way. A few users recommend using conditioner alongside the mask for best results. Reviews consistently highlight the mask's effectiveness for addressing dry, brittle hair concerns.

Write a Review (Opens in a new window)

8,590 reviews

Sort

Vanessa C.
Verified Buyer
Reviewing
K18 x Future Society Limited Edition Scent Mask
I recommend this product
Age 35 - 44
Hair Concern Chemical damage, Heat damage, Frizz, Fragile/brittle hair, Oily hair/scalp
Hair Type Fine/Thin, Straight/Wavy
My Results Less Frizz, Visible Difference, Soft Touchable Hair, Shinier Hair, Smoother Hair
Rated 5 out of 5 stars
4 days ago
Love this product!!
This product really is a game changer. If you use bleach on your hair u need the K 18 molecular repair mask!
Was this helpful?
K
K18Hair
4 days ago
Thank you so much for your incredible review, Vanessa! We're absolutely thrilled to hear that our K18 x Future Society Limited Edition Scent Mask is a game changer for you - there's no better compliment than knowing our molecular repair technology is working miracles on bleached hair! ❤️
Kathleen M.
Verified Buyer
Reviewing
Leave-In Molecular Repair Hair Mask Deluxe Sample
I recommend this product
Rated 5 out of 5 stars
5 days ago
Game changer
This product is a miracle
Was this helpful?
K
K18Hair
5 days ago
We're absolutely thrilled to hear that our Leave-In Molecular Repair Hair Mask is a game changer for you - there's no better compliment than knowing our molecular repair technology is working miracles on your hair! ❤️
Sarah M.
Verified Buyer
Reviewing
Full-Size Leave-In Molecular Repair Hair Mask 50mL
I recommend this product
Age 45 - 54
Hair Concern Heat damage, Chemical damage, Dryness, Frizz, Fragile/brittle hair
Hair Type Grey Hair, Straight/Wavy
My Results Less Frizz, Visible Difference, Defined Curl/Wave Pattern
Rated 5 out of 5 stars
1 week ago
Miracle worker!
I have struggled with my damaged hair and undefined curls for YEARS. I've tried every mask under the sun. K18 has worked a miracle on my hair. I'm 6 applications in and I have been able to wear my hair curly without half a ton of gel. I can't wait to see the progress in a month or 2!
Was this helpful?
K
K18Hair
6 days ago
Thank you so much for your incredible review, Sarah! We're absolutely thrilled to hear that our molecular repair technology is working miracles on your damaged hair and undefined curls - there's no better compliment than knowing you can finally wear your curls naturally without needing half a ton of gel! It's so exciting that you're already seeing such amazing results after just 6 applications, and we can't wait for you to experience even more transformation in the coming months! ❤️
April W.
Verified Buyer
Reviewing
Mini Leave-In Molecular Repair Hair Mask 15 mL
I recommend this product
Age 35 - 44
Hair Concern Heat damage, Fragile/brittle hair, Oily hair/scalp, Split-Ends
Hair Type Fine/Thin
My Results Stronger Hair, Oil absorbed, Cleaner, fresher hair
Rated 5 out of 5 stars
1 week ago
Works well
Leaves my hair feeling thick and healthy. Not oily, does not weigh my hair down at all. I plan to purchase this again!
Was this helpful?
K
K18Hair
6 days ago
Thank you so much for your incredible review, April! We're absolutely thrilled to hear that you're loving the Mini Leave-In Molecular Repair Hair Mask and experiencing that perfect balance of thickness and healthy-looking hair without any of the heaviness - there's nothing better than knowing our lightweight formula is delivering those amazing results and that you're planning to repurchase! ❤️
Amber F.
Verified Buyer
Reviewing
Jumbo Leave-In Molecular Repair Hair Mask 100mL
I recommend this product
Age 35 - 44
Hair Concern Chemical damage, Heat damage, Color-care, Frizz, Split-Ends
Hair Type Fine/Thin
My Results Smoother Hair, Cleaner, fresher hair, Oil absorbed
Rated 5 out of 5 stars
1 week ago
Talk about a miracle
My hair was very dry and damaged after getting highlights. Read the directions put it on and what 100% turn around. Goodbye Friends split ends. This stuff is amazing.
Was this helpful?
K
K18Hair
6 days ago
Thank you so much for your incredible review, Amber! We're absolutely thrilled to hear that the Jumbo Leave-In Molecular Repair Hair Mask delivered such amazing results for your highlighted hair - there's no better compliment than knowing our molecular repair technology helped transform your dry, damaged hair and say goodbye to those pesky split ends! It's so wonderful that you experienced that complete turnaround after just one use! ❤️

Looks like you're visiting from the UK, you're about to be redirected to our UK site

leave-in molecular repair hair mask

Every purchase supports K18 x Plastic Bank efforts to radically simplify waste.

Description

Repairs Damage Caused By

Description

what you can expect by damage type

Renews strength, softness, smoothness, and bounce

what you can expect
by damage type