Leave-in molecular repair hair mask 50mL
Leave-in molecular repair hair mask 50mL
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
full size leave-in molecular repair hair mask- 50 does per bottle.
Before and after image using detox, mask, conditioner, and oil
highly concentrated formula = a little goes a long way
Curly hair before using K18 mask and curly hair after using K18 mask.
full size leave in mask- start with 1 pump add more as needed. Mini size mask- start with 3 pumps add more as needed.
Clinically proven to reverse damage from: bleach + color, chemical services, and heat.
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Where does K18 fit into your routine? 1. Shampoo (skip conditioner) 2. Towel dry 3. K18 4. wait for minutes 5. everything else
Leave-in molecular repair hair mask 50mL
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
Before and after using k18 professional leave in hair mask and professional hair mist.
full size leave-in molecular repair hair mask- 50 does per bottle.
Before and after image using detox, mask, conditioner, and oil
highly concentrated formula = a little goes a long way
Curly hair before using K18 mask and curly hair after using K18 mask.
full size leave in mask- start with 1 pump add more as needed. Mini size mask- start with 3 pumps add more as needed.
Clinically proven to reverse damage from: bleach + color, chemical services, and heat.
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
Where does K18 fit into your routine? 1. Shampoo (skip conditioner) 2. Towel dry 3. K18 4. wait for minutes 5. everything else
tile bestseller | color: black
4.9
Rated 4.9 out of 5 stars
2,162 Reviews

full-size leave-in molecular repair hair mask

Retail size of our 4-minute leave-in treatment to reverse hair damage
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Description

A retail-sized version of the K18 mask helps to maintain your client's hair strength and elasticity in-between salon appointments. This leave-in treatment mask for all hair types that reverses damage in 4 minutes. Patented peptide technology works to repair damage from bleach + color, chemical services, and heat* — restoring 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 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

Takes damage repair further – biomimetic peptide seamlessly fits in and reconnects 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 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 and with every service

  • 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, and heat*.

  • pH-optimized (5.0-6.0) to help minimize cuticle swelling + put hair proteins in their most resilient state after salon service or shampoo

  • Cream format enables easy, lightweight application across all hair types, with detangling and softening benefits.

  • Vegan, color-safe, cruelty-free

  • DO clarify before K18 if your client is 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
  • 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
4.9
Rated 4.9 out of 5 stars
466 Reviews
Weightless oil that strengthens, repairs damage + reduces frizz View Product
PEPTIDE PREP™ detox shampoo
4.9
Rated 4.9 out of 5 stars
284 Reviews
Retail size of our color-safe, non-stripping clarifying shampoo formulated with the K18PEPTIDE™ View Product

Description

A retail-sized version of the K18 mask helps to maintain your client's hair strength and elasticity in-between salon appointments. This leave-in treatment mask for all hair types that reverses damage in 4 minutes. Patented peptide technology works to repair damage from bleach + color, chemical services, and heat* — restoring strength, softness, smoothness, and bounce to hair.

20+ billion TikTok views 🔥 

*Disclaimers

got questions?
Get started here
K18 is engineered to work with every hair type, in every service, and with every routine.
Traditional conditioners leave a film on hair 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 styling product.
Water in damp hair swells the cuticle (the outside layer of hair) to open the gates for our biomimetic peptide to enter and travel to the innermost layers of hair. If the gates aren’t open, the product will stay on the surface—giving you mostly superficial repair. By applying on damp hair, you can use less, waste less, and still get the best results.
Think of the K18 mask as a highly concentrated treatment. It restores hair’s strength + elasticity in the innermost layers of hair, instead of traditional conditioners that coat the outside of hair. After the 4-minute wait time post-K18 mask, feel free to add a leave-in for a boost of conditioning if needed.
Yes, both formulas are the same. The PRO mask is conveniently sized for PRO use.

healthier hair with every use

Reverse damage in 4 minutes with our breakthrough K18 molecular repair technology.
how to use K18
lightener / color
1. Section dry hair into 4 quadrants.

2. Apply a minimum of 10 full sprays of K18 professional molecular repair hair mist to each quadrant, increasing up to 20 sprays per quadrant as needed, depending on client’s length, density, or level of damage.

3. Wait 4 minutes (do not rinse out).

4. If needed, dry the hair prior to applying lightener or color. Then perform your desired technique.

5. Process your lightener or color as usual, then rinse and shampoo with K18 PEPTIDE PREP™ detox shampoo. Do not condition.

6. Apply 1-3 pumps of K18 professional molecular repair hair mask based on your client’s length and density, starting at the ends and working up towards the roots.

7. Wait 4 minutes (do not rinse), then apply 1-3 drops of K18 molecular repair hair oil to mid-lengths and ends.

8. Wait 4 minutes, then proceed with cut or style as usual.

9. Add an additional 1-3 drops of K18 molecular repair hair oil to dry hair as a finisher.

Please see the “K18 + toning or glossing” section for more information on toning with K18.
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how molecular repair compares
how K18 works

Traveling into the innermost layers of hair, our K18PEPTIDE™ renews strength along the width AND length of hair for lasting strength where it matters.

feel what's possible with K18
See how K18 unlocks our community's expression
4.9
Rated 4.9 out of 5 stars
Based on 2,162 reviews
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2,162 reviews
  • Cindy K. S.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
    I recommend this product
    Age 45 - 54
    Hair Concern Chemical damage, Frizz, Heat damage, Fragile/brittle hair, Dryness
    Hair Type Fine/Thin, Straight/Wavy
    My Results Less Frizz, Bouncy Hair, Visible Difference, Defined Curl/Wave Pattern, Soft Touchable Hair
    Rated 5 out of 5 stars
    Yesterday
    Fine curly hair

    Saved my fine curly bleached hair!! Can’t go without K18

    Was this helpful?
  • Sabrina C.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
    I recommend this product
    Age 35 - 44
    Hair Concern Chemical damage, Fragile/brittle hair, Split-Ends, Color-care
    Hair Type Straight/Wavy, Medium Density
    My Results Bouncy Hair, Less Breakage, Smoother Hair, Shinier Hair, Soft Touchable Hair
    Rated 5 out of 5 stars
    3 days ago
    Hair repair

    I can’t live without my k18 mask!! It’s made a huge difference in the look and feel of my hair, I’ve been coloring for years and this stuff saves me from breakage.

    Was this helpful?
    K18Hair PRO
    3 days ago

    Thank you so much for the 5 stars, Sabrina! We're absolutely thrilled to hear the K18 mask has made such a huge difference for your hair—especially after years of coloring. Protecting against breakage while keeping your hair looking and feeling amazing is exactly what we're all about! ✨ So glad you can't live without it—that's the best compliment we could ask for!

  • Kaci C.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
    I recommend this product
    Age 35 - 44
    Hair Concern Color-care, Heat damage, Chemical damage, Extending time between washes
    Hair Type Fine/Thin, Grey Hair
    My Results Less Breakage, Cleaner, fresher hair, Soft Touchable Hair, Stronger Hair, Visible Difference
    Rated 5 out of 5 stars
    4 days ago
    Does wonders for my hair.

    I am a brunette who has gone through a bleaching journey to achieve gray/silver hair. K18 has been a savior for my hair to keep it healthy. So glad my stylist told me about it

    Was this helpful?
    K18Hair PRO
    3 days ago

    Thank you so much for this incredible review, Kaci! 💛 We're absolutely thrilled to hear that K18 has been such a savior for your hair during your bleaching journey to achieve that gorgeous gray/silver look! ✨ It's amazing that you can feel how it's keeping your hair healthy through such a transformative process - that's exactly what molecular repair is designed to do, rebuilding your hair's strength from the inside out. We're so glad your stylist introduced you to K18 and that it's doing such wonders for your hair! Thanks for your wonderful 5-star review! 🙌

  • Geneve H.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
    I recommend this product
    Age 55 - 64
    Hair Concern Heat damage
    Hair Type Grey Hair, Medium Density, Fine/Thin, Curly/Coily
    My Results Visible Difference, Less Frizz, Less Breakage
    Rated 5 out of 5 stars
    1 week ago
    IT’S WORKING!

    My hairdresser always educates and guides me for my hair care and never steers me wrong. Even with heat protection, I fried my hair pretty good, not to mention I moved from CA to CO and it’s very dry here and water is hard. I knew I would need more than three treatments as you will see in the picture, BUT it’s definitely noticeable. I’m still not putting heat to my hair to give it complete restoration. However, this is worth the money because it DEFINITELY is working. Thank you K18!

    Was this helpful?
    K18Hair PRO
    6 days ago

    Geneve, we're so excited to hear about your progress! 🙌 It sounds like you've been through a lot with the move and environmental changes, but we're thrilled the Molecular Repair Mask is making such a noticeable difference already. Your hairdresser sounds amazing, and we love that you're being so patient with the restoration process by avoiding heat. Thank you for sharing your journey with us - results like yours are exactly why we do what we do! ✨💛

  • Kiersten V.
    Verified Buyer
    Reviewing
    Full-Size Leave-In Molecular Repair Hair Mask 50 mL (WHOLESALE)
    I recommend this product
    Age 25 - 34
    Hair Concern Heat damage, Dryness, Fragile/brittle hair, Chemical damage
    Hair Type Fine/Thin
    My Results Less Frizz, Stronger Hair, Less Breakage, Smoother Hair, Visible Difference
    Rated 5 out of 5 stars
    1 week ago
    HAIR FOOD

    I was honestly at the point where I thought my hair was beyond saving—years of bleaching left it dry, brittle, and constantly breaking. Then I tried the K18 hair mask, and I can genuinely say it completely transformed my hair.

    After just a few uses, my bleach-blonde hair went from feeling like straw to actually soft, smooth, and healthy again. It doesn’t just sit on top of your hair like a typical conditioner—it feels like it actually repairs it from the inside out. My ends look less fried, my hair feels stronger, and I’ve even noticed less breakage when brushing.

    What really surprised me is how lightweight it is. My hair feels silky without being weighed down or greasy, which is rare for something this hydrating. It’s like my hair finally has life in it again.

    If your hair is dry, damaged, or over-processed like mine was, this is absolutely worth it. It didn’t just improve my hair—it genuinely saved it.

    Was this helpful?
    K18Hair PRO
    1 week ago

    Thank you so much for your incredible review, Kiersten! 💛 We're absolutely thrilled to hear about your amazing hair transformation - going from feeling like your hair was beyond saving to having it completely transformed is exactly what K18 is all about! ✨ It sounds like you've experienced the true power of molecular repair, and we're so excited that your bleach-blonde hair went from straw-like to soft, smooth, and healthy again. We love that you can feel the difference of how it actually repairs from the inside out rather than just sitting on top like typical conditioners! The fact that you're seeing less breakage, stronger hair, and healthier-looking ends while still maintaining that lightweight, silky feel without any greasiness is absolutely wonderful to hear. Your hair definitely has life in it again, and we couldn't be more excited for you! Thanks for your fantastic 5-star review! 🙌