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Leave-in molecular repair hair mask 15mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
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.
get stronger, more resilient hair. left - 8x bleach without K18, right 8x bleach with K18
the K18 routine
Mini Leave-In Molecular Repair Hair Mask 15 mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
less is more
works for all hair types
where does K18 fit into your routine?
Mini versus full size product comparison
Mini Leave-In Molecular Repair Hair Mask 15 mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
K18 routine guide
Leave-in molecular repair hair mask 15mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
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.
get stronger, more resilient hair. left - 8x bleach without K18, right 8x bleach with K18
the K18 routine
Mini Leave-In Molecular Repair Hair Mask 15 mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
less is more
works for all hair types
where does K18 fit into your routine?
Mini versus full size product comparison
Mini Leave-In Molecular Repair Hair Mask 15 mL
Mini Leave-In Molecular Repair Hair Mask 15 mL
K18 routine guide
4.7
Rated 4.7 out of 5 stars
8,150 Reviews

mini leave-in molecular repair hair mask

4-minute leave-in treatment to reverse hair damage

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
  1. Shampoo, do not condition. Towel-dry thoroughly.
  2. Apply 3-9 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.
  • 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.

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.

  • 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.

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
Molecular repair hair oil
4.8
Rated 4.8 out of 5 stars
954 Reviews
Weightless oil that strengthens, repairs damage + reduces frizz
PEPTIDE PREP™ detox shampoo
4.9
Rated 4.9 out of 5 stars
547 Reviews
Color-safe, non-stripping clarifying shampoo with the K18PEPTIDE™

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.
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.
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*

*k18hair.co.uk/disclaimers
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.
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).
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.
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.

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.
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 8,150 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
8,150 reviews
  • Ottonella V. O. V.
    Verified Buyer
    Reviewing
    Jumbo Leave-In Molecular Repair Hair Mask 100mL
    I recommend this product
    Age 25 - 34
    Hair Concern Chemical damage, Heat damage, Color-care
    Hair Type Medium Density
    My Results Bouncy Hair, Visible Difference, Stronger Hair, Less Breakage, Soft Touchable Hair
    Rated 5 out of 5 stars
    1 hour ago
    Changed my hair

    My hair is bleached and relaxed since 17y ago and k18 is my savior, I'm on my 15th application and I'm obsessed

    KU Profile picture for K18Hair UK
    K18Hair UK
    4 minutes ago

    Thank you for the amazing review, Ottonella! We're thrilled to hear the Molecular Repair Hair Mask has been your savior for your bleached and relaxed hair. Your transformation sounds incredible!

  • Danielle M.
    Verified Buyer
    Reviewing
    Leave-In Molecular Repair Hair Mask Sample
    I recommend this product
    Rated 5 out of 5 stars
    9 hours ago
    Smooth hair

    I tried this sample on my hair and it made feel so smooth and my hair feels balanced

    KU Profile picture for K18Hair UK
    K18Hair UK
    9 hours ago

    Thank you for your amazing review, Danielle! We're so thrilled to hear the Leave-In Molecular Repair Hair Mask Sample left your hair feeling smooth and balanced - that's exactly what we love to see! It's incredible how the right product can make such a difference in how your hair feels. We're so happy the sample could give you a chance to experience those game-changing results. Thank you for choosing K18 and for sharing your experience with us! ✨

  • Nucole N.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50mL
    I recommend this product
    Age 25 - 34
    Hair Concern Heat damage, Chemical damage
    Hair Type Curly/Coily
    My Results Stronger Hair, Defined Curl/Wave Pattern
    Rated 5 out of 5 stars
    Yesterday
    K18

    I have been using this for a week now and I have great results my curls are coming back so much better still have a long way to go but this product is amazing

    KU Profile picture for K18Hair UK
    K18Hair UK
    Yesterday

    Thank you for the wonderful review! We're so happy to hear your curls are coming back and that you're seeing great results with the Molecular Repair Hair Mask already!

  • Nataliia M.
    Verified Buyer
    Reviewing
    Jumbo Leave-In Molecular Repair Hair Mask 100mL
    I recommend this product
    Age 45 - 54
    Hair Concern Chemical damage, Dryness, Fragile/brittle hair, Heat damage, Frizz
    Hair Type Medium Density
    My Results Visible Difference, Stronger Hair, Less Breakage, Less Frizz, Shinier Hair
    Rated 5 out of 5 stars
    Yesterday
    Great!

    Absolutely love this hair mask! It made my hair feel softer, smoother, and healthier after just a few uses. The texture is lightweight and doesn’t weigh my hair down. My hair looks shinier and feels more repaired and hydrated. Definitely worth trying!

    KU Profile picture for K18Hair UK
    K18Hair UK
    Yesterday

    Thank you for your amazing review, Nataliia! We're absolutely thrilled to hear that the Jumbo Leave-In Molecular Repair Hair Mask is delivering such incredible results for you! It's wonderful that you're seeing softer, smoother, and healthier hair after just a few uses - that's exactly what we love to see. We're so happy the lightweight texture works perfectly for your hair without weighing it down, and that you're noticing that beautiful shine and improved hydration. Thank you for choosing K18 and for sharing your experience with us! ✨

  • Lindsey F.
    Verified Buyer
    Reviewing
    Mini Leave-In Molecular Repair Hair Mask 15 mL
    I recommend this product
    Age 65+
    Hair Concern Chemical damage, Heat damage, Frizz, Dryness
    Hair Type Thick/Coarse, Grey Hair
    My Results Visible Difference, Stronger Hair, Smoother Hair, Less Breakage, Less Frizz
    Rated 5 out of 5 stars
    Yesterday
    Leave in molecular repair mask

    Seems to work extremely well on my damaged over processed hair. I tried a sample first and ended up buying more. I’m happy with the results.

    KU Profile picture for K18Hair UK
    K18Hair UK
    Yesterday

    Thank you for the wonderful review! We're so happy to hear the Leave-In Molecular Repair Mask is working extremely well for your damaged hair. Thanks for sharing your experience!

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