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Jumbo Leave-In Molecular Repair Hair Mask 100mL
Regular price £120
Regular price £0 Sale price £120
Jumbo Leave-In Molecular Repair Hair Mask 100mL
Mini, Full, and Jumbo size leave in molecular repair masks lined up next to each other on a pink background.
Grey curly hair before and after results using k18.
Red 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
K18 mask benefits
where K18 molecular repair works
the K18 routine
maximze your repair
less is more
works for all hair types
where does K18 fit into your routine?
K18 routine guide
Jumbo Leave-In Molecular Repair Hair Mask 100mL
Mini, Full, and Jumbo size leave in molecular repair masks lined up next to each other on a pink background.
Grey curly hair before and after results using k18.
Red 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
K18 mask benefits
where K18 molecular repair works
the K18 routine
maximze your repair
less is more
works for all hair types
where does K18 fit into your routine?
Jumbo Leave-In Molecular Repair Hair Mask 100mL
K18 routine guide
4.7
Rated 4.7 out of 5 stars
8,784 Reviews
bestseller

jumbo leave-in molecular repair hair mask

4-minute leave-in treatment - now in an exclusive jumbo size

Size:
100 mL
Regular price £120
Regular price £0 Sale price £120
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Color:
100 mL

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Jumbo Leave-In Molecular Repair Hair Mask 100mL

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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

    • 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, 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.

pairs well with
FutureIQ™ biomimetic hair longevity serum
Jumbo DAMAGE SHIELD protective conditioner
Press + and − keys to zoom, arrow keys to pan.
Jumbo Leave-In Molecular Repair Hair Mask 100mL
Mini, Full, and Jumbo size leave in molecular repair masks lined up next to each other on a pink background.
Grey curly hair before and after results using k18.
Red 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
K18 mask benefits
where K18 molecular repair works
the K18 routine
maximze your repair
less is more
works for all hair types
where does K18 fit into your routine?
K18 routine guide
Jumbo Leave-In Molecular Repair Hair Mask 100mL
Mini, Full, and Jumbo size leave in molecular repair masks lined up next to each other on a pink background.
Grey curly hair before and after results using k18.
Red 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
K18 mask benefits
where K18 molecular repair works
the K18 routine
maximze your repair
less is more
works for all hair types
where does K18 fit into your routine?
K18 routine guide
got questions?

still have questions? visit our help center

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 afer
before
after
"I absolutely love this product!! You have to see it to believe it!"
- Christina Marie P.
before afer
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 afer
before
after
"Amazing the way it feels and the shine provides to the hair instantly."
- Sandra M.
before afer
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 afer
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 afer
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 afer
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 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

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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 8,784 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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8,784 reviews
  • Carolina F.
    Verified Buyer
    Reviewing
    Jumbo Leave-In Molecular Repair Hair Mask 100mL
    I recommend this product
    Age 18 - 24
    Hair Concern Chemical damage, Split-Ends
    Hair Type Thick/Coarse
    My Results Visible Difference, Stronger Hair, Less Breakage, Shinier Hair, Soft Touchable Hair
    Rated 5 out of 5 stars
    45 minutes ago
    amazing product

    i have bleached damaged hair and this is the only product that has made a difference in my hair. i love it

    Was this helpful?
    KU Profile picture for K18Hair UK
    K18Hair UK
    9 minutes ago

    We're so thrilled to hear that the Jumbo Leave-In Molecular Repair Hair Mask has made such a difference for your bleached damaged hair, Carolina! 💚 We love that you're seeing real results and that this product has become a go-to in your routine. Thank you so much for sharing your love and for being part of the K18 community! ✨

  • Julie K.
    Verified Buyer
    Reviewing
    Jumbo Leave-In Molecular Repair Hair Mask 100mL
    I recommend this product
    Age 55 - 64
    Hair Concern Color-care, Split-Ends, Frizz
    Hair Type Thick/Coarse
    My Results Less Frizz, Bouncy Hair, Visible Difference, Smoother Hair, Stronger Hair
    Rated 5 out of 5 stars
    1 hour ago
    This is life changing!

    I started using this a month ago and my hair is stronger and healthier, I am addicted!

    Was this helpful?
    KU Profile picture for K18Hair UK
    K18Hair UK
    8 minutes ago

    We're so thrilled to hear that the Jumbo Leave-In Molecular Repair Hair Mask has been life changing for you, Julie! 💚 We love that you're seeing stronger, healthier hair and that you're already addicted after just a month. Thank you so much for sharing your amazing results and for being part of the K18 community! ✨

  • katerina M.
    Verified Buyer
    Reviewing
    Leave-In Molecular Repair Hair Mask Sample
    I recommend this product
    Rated 5 out of 5 stars
    2 hours ago
    Excellent mask

    I love this mask. It provides excellent hydration. I use it once a week. It leaves my hair soft and manageable.

    Was this helpful?
    KU Profile picture for K18Hair UK
    K18Hair UK
    1 hour ago

    We're so happy you're loving the Leave-In Molecular Repair Mask! 💚 Thanks for sharing your experience and for being part of the K18 community!

  • Katherine K.
    Verified Buyer
    Reviewing
    Jumbo Leave-In Molecular Repair Hair Mask 100mL
    I recommend this product
    Age 65+
    Hair Concern Chemical damage, Heat damage, Split-Ends
    Hair Type Fine/Thin
    My Results Bouncy Hair, Visible Difference, Stronger Hair, Shinier Hair
    Rated 5 out of 5 stars
    3 hours ago
    Mask

    Absolutely love love love this product. It protects your hair better than anything I’ve ever found. I happen to be in Oklahoma and a girl told me a BD operator told me about this product. She didn’t know much about it but had heard about it and my hair was breaking off so bad so I tried it. It’s the best there’s nothing compared to it.

    Was this helpful?
    KU Profile picture for K18Hair UK
    K18Hair UK
    1 hour ago

    We're so thrilled you're loving the Jumbo Leave-In Molecular Repair Hair Mask! 💚 Thank you for sharing your experience and for being part of the K18 community!

  • Ebru B.
    Verified Buyer
    Reviewing
    Mini Leave-In Molecular Repair Hair Mask 15 mL
    I recommend this product
    Age 35 - 44
    Hair Concern Chemical damage, Color-care, Frizz
    Hair Type Medium Density
    My Results Visible Difference, Shinier Hair
    Rated 5 out of 5 stars
    4 hours ago
    Great product

    The improvement was immediate, even my hairdresser noticed it before I said anything. I will report back after 5-6 use. So far so good!!

    Was this helpful?
    KU Profile picture for K18Hair UK
    K18Hair UK
    3 hours ago

    We're so thrilled you're already seeing amazing results! 💚 We love that your hairdresser noticed the improvement too. Thanks for sharing and we can't wait to hear how you love it!

*Disclaimers

10