Leave-in molecular repair hair mask 50mL

Full-Size Leave-In Molecular Repair Hair Mask 50mL

Red curly hair before and after results using k18.

Grey curly hair before and after results using k18.

Bleach blonde hair before and after results using k18.

get stronger, more resilient hair. left - 8x bleach without K18, right 8x bleach with K18

4.7

Rated 4.7 out of 5 stars

9,232 Reviews

bestseller

full-size leave-in molecular repair hair mask

Name: Full-Size Leave-In Molecular Repair Hair Mask 50mL
Brand: K18Hair
SKU: K18-31005
Price: 75.00 USD
Availability: InStock
Rating: 4.7 (9232 reviews)

4-minute leave-in treatment to reverse hair damage

Full Size - 50mL$75.00 Jumbo Size - 100mL$120.00 Mini Size - 15mL$29.00 Limited-Edition Scent - 50 mL$75.00

$75

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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.

20+ billion TikTok views 🔥

*Disclaimers

Repairs Damage Caused By

Bleach + Color

Heat

Chemical Services

- ingredients
  
  Water (Aqua) (Eau), Alcohol Denat., Propylene Glycol, Cetearyl Alcohol, Dicaprylyl Ether, Cetyl Esters, Behentrimonium Chloride, Polysorbate 20, sh- Oligopeptide-78, Hydrolyzed Wheat Protein, Hydrolyzed Wheat Starch, Isopropyl Alcohol, Tocopherol, Phenoxyethanol, Potassium Sorbate, Citric Acid, Fragrance (Parfum), Geraniol, Linalool, Hexyl Cinnamal, Benzyl Alcohol, Amyl Salicylate, Benzaldehyde.
- 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.
- 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.
- 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.
- 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.

pairs well with

FutureIQ™ biomimetic hair longevity serum

PEPTIDE PREP™ detox shampoo

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.

soft, strong, bouncy hair for everyone

Repair damage for hair like new* in 4 minutes.

before

after

"I absolutely love this product!! You have to see it to believe it!"

- Christina Marie P.

before

after

“…I had my hair chopped (it was begging for it) along with some highlights and coloring of the roots. My hair stylist used this on my hair and I absolutely loved how it made my hair feel ... I love this mask so much!”

- Ashley P.

before

after

"Amazing the way it feels and the shine provides to the hair instantly."

- Sandra M.

before

after

"I’ve been using this mask for about four washes so far. I feel that my hair is getting healthier."

- Olga S.

before

after

"It makes my hair so soft and weightless, I absolutely love it... Makes my hair feel so luxurious, it’s like I just left the salon. Can’t recommend this product more!"

- Anastasiia T.

before

after

"My hair has been a mess for years... My new hair stylist recommended K18! ... My hair looks and feels amazing with lasting results!!"

- Arnell M

before

after

"I have heat damaged color treated curly hair and this has improved my hair health immensely...This is one of those products that has incorporated itself into my routine for the rest of my life..."

- Siria A.

powered by K18PEPTIDE™

Biomimetic peptide clicks into hair’s keratin structure—the source of core strength—for soft, shiny, bouncy results that won’t wash away.

Explore the Science

how to use molecular repair mask

1. Shampoo, do not condition. Towel-dry thoroughly.

2. Apply 1-3 pumps 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 styling product + style as usual. Use for 4-6 washes, then as needed.

*k18hair.com/disclaimers

learn more on our blog

October 24, 2024 / products

How much leave-in mask do you *really* need?

Find your optimal dose with this easy guide.

March 23, 2023 / hair science

The Science Behind K18 Molecular Repair

See how our K18PEPTIDE™-powered mask reverses damage in 4 minutes for lasting...

December 08, 2024 / products

The Top K18 Mask FAQs

answering your most-asked questions.

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feel what's possible with K18

See how K18 unlocks our community's expression

4.7

Rated 4.7 out of 5 stars

Based on 9,232 reviews

93%would recommend these products

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.

Customers Talked About

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9,232 reviews

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Linda
Reviewing
Full-Size Leave-In Molecular Repair Hair Mask 50mL
I recommend this product
Rated 5 out of 5 stars
4 minutes ago
5 Stars
Love this product- follow the instructions and it does what it says 💝
Was this helpful?
Lashandra
Reviewing
Leave-In Molecular Repair Hair Mask Deluxe Sample
I recommend this product
Rated 5 out of 5 stars
54 minutes ago
5 Stars
I love this product. This is great product is fast and quick and easy use and it smooth and seals the hair and it’s not too heavy. I love it.
Was this helpful?
Junai M. T.
Verified Buyer
Reviewing
Jumbo Leave-In Molecular Repair Hair Mask 100mL
I recommend this product
Age 25 - 34
Hair Concern Split-Ends, Fragile/brittle hair, Heat damage, Chemical damage
Hair Type Thick/Coarse
My Results Less Breakage, Stronger Hair, Soft Touchable Hair
Rated 5 out of 5 stars
3 hours ago
The best
The title says it all. Completely has changed my hair
Was this helpful?
K
K18Hair
3 hours ago
Thank you so much Junai! We love hearing this! 💕 We're thrilled that the Jumbo Leave-In Molecular Repair Hair Mask has made such an amazing difference for your hair. Your kind words mean the world to us! ✨
Kevin
Reviewing
Jumbo Leave-In Molecular Repair Hair Mask 100mL
I recommend this product
Rated 5 out of 5 stars
3 hours ago
5 Stars
On my second use today. So far I’m pleased but trusting the process and hoping for even better results after 4-6 uses.
Was this helpful?
K
K18Hair
3 hours ago
Thank you for sharing your experience! 💙 We’re so glad you’re already pleased after your second use. Trusting the process is key, and we hope you continue to see your hair feeling stronger, healthier, and more resilient with continued use. ✨ Here’s to even better results!
Denise B.
Verified Buyer
Reviewing
Jumbo Leave-In Molecular Repair Hair Mask 100mL
I recommend this product
Age 35 - 44
Hair Concern Dryness, Extending time between washes
Hair Type Medium Density, Curly/Coily
My Results Visible Difference, Less Breakage, Stronger Hair, Soft Touchable Hair, Smoother Hair
Rated 5 out of 5 stars
4 hours ago
Staunch Leave In Girly Turned K18 Fan
When I first learned that no conditioner was to be used prior to this mask, I was horrified - nonetheless, I applied as instructed followed by the oil (after the 4min wait), and my horror turned to amazement.
My 3b/c hair loves this stuff and it turns wash day into something I don’t dread, with regard to time.
Was this helpful?
K
K18Hair
4 hours ago
Thank you so much for your wonderful review, Denise! 💕 We love that you were willing to try something different and that the Jumbo Leave-In Molecular Repair Hair Mask completely won you over! It's amazing to hear that your 3b/c hair is thriving and that wash day has become so much easier for you. Your kind words mean everything to us, and we're so happy K18 has made such a noticeable difference in your routine! ✨

*Disclaimers