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

£70

Leave-in molecular repair hair mask 50mL

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

Grey curly hair before and after results using k18.

Bleach blonde hair before and after results using k18.

Red curly hair before and after results using k18.

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

Mini versus full size product comparison

4.7

Rated 4.7 out of 5 stars

8,521 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: 70.00 GBP
Availability: InStock

4-minute leave-in treatment to reverse hair damage

Full Size - 50 mL£70.00 Jumbo Size - 100 mL£120.00 Mini Size - 15 mL£30.00

£70

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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

PEPTIDE PREP™ detox shampoo

FutureIQ™ biomimetic hair longevity serum

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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4.7

Rated 4.7 out of 5 stars

Based on 8,521 reviews

93%would recommend these products

Reviews Summary

Customers say this hair mask transforms damaged, bleached, and chemically-treated hair, making it softer, stronger, and more manageable. Many report significant improvements in hair texture, with reduced breakage, split ends, and frizz. Users with curly hair find it enhances curl definition and reduces dryness. The lightweight formula doesn't weigh hair down or leave residue. Many reviews mention it works particularly well for bleached hair, helping restore smoothness and shine. Some note the price is high but find it worthwhile since only small amounts are needed per use.

Customers Talked About

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8,521 reviews

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Robin L. G.
Verified Buyer
Reviewing
Full-Size Leave-In Molecular Repair Hair Mask 50mL
I recommend this product
Age 35 - 44
Hair Concern Chemical damage, Heat damage, Color-care, Dryness
Hair Type Fine/Thin
My Results Visible Difference, Soft Touchable Hair, Cleaner, fresher hair, Stronger Hair
Rated 5 out of 5 stars
4 hours ago
The best
Noticed significant difference/ progress from the first Used stash. Look forward to seeing what it looks like after four washes.
Was this helpful?
KU
K18Hair UK
3 hours ago
Thank you so much for the 5-star review, Robin! We're thrilled you're already noticing amazing results with the Full-Size Leave-In Molecular Repair Hair Mask! 💙✨
Paris L.
Verified Buyer
Reviewing
Jumbo Leave-In Molecular Repair Hair Mask 100mL
I recommend this product
Age 25 - 34
Hair Concern Chemical damage, Dryness, Fragile/brittle hair, Oily hair/scalp, Split-Ends
Hair Type Medium Density, Thick/Coarse
My Results Visible Difference, Bouncy Hair, Soft Touchable Hair
Rated 5 out of 5 stars
11 hours ago
Jumbo Leave-In
I love it so much!!! I wish I could give 6 stars!!!
Was this helpful?
KU
K18Hair UK
10 hours ago
Thank you so much for the love, Paris! 💙 We're thrilled you're loving the Jumbo Leave-In Molecular Repair Hair Mask so much! ✨ We truly appreciate your support!
Martin B.
Verified Buyer
Reviewing
Full-Size Leave-In Molecular Repair Hair Mask 50mL
I recommend this product
Rated 5 out of 5 stars
16 hours ago
K18
I have only just started to use it now because my hair is really damaged every one says use k18 but up to now am liking it and soon my hair will get back stronger again
Was this helpful?
KU
K18Hair UK
15 hours ago
Thank you so much Martin! We're thrilled you're loving the Full-Size Leave-In Molecular Repair Hair Mask! 💕 Here's to your hair getting stronger again! ✨
Sandra L.
Verified Buyer
Reviewing
Full-Size Leave-In Molecular Repair Hair Mask 50mL
I recommend this product
Age 55 - 64
Hair Concern Heat damage, Fragile/brittle hair, Dryness
Hair Type Curly/Coily, Thick/Coarse
My Results Less Frizz, Visible Difference
Rated 5 out of 5 stars
2 days ago
k-18 reviews
Most amazing product for my thick, naturally curly hair
Was this helpful?
KU
K18Hair UK
2 days ago
Thank you so much for the love! 💙 We're thrilled to hear the Full-Size Leave-In Molecular Repair Hair Mask is working amazingly for your thick, curly hair! ✨
Juliana T.
Verified Buyer
Reviewing
Leave-In Molecular Repair Hair Mask Sample
I recommend this product
Rated 5 out of 5 stars
3 days ago
Sample was amazing, bought the actual product.
Combined with the serum and oil it has been lifechanging.
Was this helpful?
KU
K18Hair UK
3 days ago
Thank you so much, Juliana! We're thrilled the sample convinced you to get the full size, and that the Leave-In Molecular Repair Hair Mask is making such a difference for you! 💕✨

*Disclaimers