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K18 Leave-In Molecular Hair Mask, Repairs Dry or Damaged Hair, Reverse Hair Damage from Bleach, Color, Chemical Services & Heat
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Return this item for free
We offer easy, convenient returns with at least one free return option: no shipping charges. All returns must comply with our returns policy.
Learn more about free returns.- Go to your orders and start the return
- Select your preferred free shipping option
- Drop off and leave!
Bundles with this item
Purchase options and add-ons
Brand | K18 |
Item Form | Cream |
Material Feature | Natural |
Hair Type | Damaged |
Product Benefits | Our K18PEPTIDE™ repairs hair at a molecular level across multiple types of bonds, restoring hair health for all See more |
Additional Details


Description
Benefits
Suggested use
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Shop damage repair mask
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Shop weightless dry shampoo
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Shop shampoo + conditioner
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Product Description



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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.
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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.
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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.
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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.
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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.
Shop the K18 Collection
![]() Molecular Repair Mask | ![]() Molecular Repair Oil | ![]() Damage Shield Shampoo | ![]() Detox Shampoo | ![]() Damage Shield Conditioner | ![]() AirWash | |
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Customer Reviews
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4.3 out of 5 stars 22,366
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4.4 out of 5 stars 1,266
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4.5 out of 5 stars 485
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4.6 out of 5 stars 1,393
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4.5 out of 5 stars 570
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4.2 out of 5 stars 196
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Price
| $75.00$75.00 | $65.00$65.00 | $36.00$36.00 | $38.00$38.00 | $36.00$36.00 | $48.00$48.00 |
Molecular Repair
| ✔ | ✔ | ✘ | ✘ | ✘ | ✘ |
Maintenance Routine
| ✘ | ✘ | ✔ | ✘ | ✔ | ✔ |
Treatment Routine
| ✔ | ✔ | ✘ | ✔ | ✘ | ✘ |
Used By Professionals
| ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
At Home Use
| ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
Product details
- Product Dimensions : 1.9 x 1.9 x 4 inches; 3.2 ounces
- Item model number : K18-31005
- UPC : 858511001029 858511001128 729162271362 729162270877 755801147958 726929222179 729162271317 729162271249 729162271096
- Manufacturer : K18
- ASIN : B0961ZS96M
- Country of Origin : USA
- Best Sellers Rank: #306 in Beauty & Personal Care (See Top 100 in Beauty & Personal Care)
- #4 in Hair Treatment Masks
- Customer Reviews:
Videos
Videos for this product
1:39
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DOES IT WORK? K18 Leave-In Molecular Repair Hair Treatment
Ryan
Videos for this product
1:44
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K18 peptide for strengthening and repairing hair
Geri Terranova
Videos for this product
2:36
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How to use k18 on thick, coarse, dry hair
Why Reviews
Videos for this product
1:35
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K18 Professional Molecular Repair Mask
K18 Hair
Videos for this product
1:22
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The good and bad about this Hair Mask
Callie Ammons 🔵
Videos for this product
2:11
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Do you have bad ends like me? WATCH TILL THE END
Fruit of Her House
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Customer reviews
Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.
To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzed reviews to verify trustworthiness.
Learn more how customers reviews work on AmazonCustomers say
Customers find the hair mask effective and appreciate its ability to make hair softer, smooth, and shiny. The product receives mixed feedback regarding hair repair and strength - while some say it helped revive their hair, others report it didn't improve quality, and while some find it stronger than before, others note it becomes brittle over time. Additionally, customers disagree on whether it helps with dryness and frizz, and many find the bottle size too small for the price.
AI-generated from the text of customer reviews
Customers find the hair mask works well, with one noting that the results improve with continued use.
"...But it is an amazing product & by far the best leave in conditioner that has actually controlled frizz, and left my hair soft...." Read more
"...It’s worth a try if your hair is damaged from bleach 👌🏼..." Read more
"...The formula is super easy to apply, and a little goes a long way. I’ve noticed my hair feeling softer, looking shinier, and overall much healthier...." Read more
"...While it’s on the pricier side, its effectiveness and quality make it worth every penny...." Read more
Customers report that the hair mask makes their hair softer, smoother, and frizz-free, with one customer noting their hair has never been shinier or softer.
"...left my ends feeling like a straw, but this immediately left my hair looking healthy and hydrated...." Read more
"...My hair was so soft, shiny, not a tangled hot mess and just looked healthier. I bit the bullet after seeing this all over social media...." Read more
"...The breakage has dramatically reduced, and the texture has improved—my hair feels stronger and more manageable...." Read more
"Used it once and it brought out the curls in my recent perm. Softer hair. It's pricey, but it works." Read more
Customers report that the hair mask makes their strands look shinier and healthier, with one customer noting that their hair has maintained this appearance for six months.
"...The K18 has helped with the damage, added shine back to my hair, and lessened the amount of hair that falls out...." Read more
"...My hair was so soft, shiny, not a tangled hot mess and just looked healthier. I bit the bullet after seeing this all over social media...." Read more
"...I’ve noticed my hair feeling softer, looking shinier, and overall much healthier...." Read more
"...the difference is very noticeable - my hair looks so much healthier, shinier and more bouncy...." Read more
Customers have mixed experiences with the hair mask's repair capabilities, with some reporting that it helped revive their hair and saved it, while others found it did not improve their hair quality or was not healthy for their strands.
"...The K18 has helped with the damage, added shine back to my hair, and lessened the amount of hair that falls out...." Read more
"Went from box dark brown neutral dye, to blonde in one sitting. Damage was present. I walked out with bangs! HAHA...." Read more
"This stuff is an absolute miracle in a bottle. It has fixed my hair after an unfortunate visit to a salon which left my hair extremely bleach..." Read more
"I cannot rave enough about the K18 Hair Mask—it has truly saved my hair! I used to pull my hair every day, causing so much damage and breakage...." Read more
Customers have mixed experiences with the hair mask's strength, with some reporting that their hair becomes stronger and breakage stops, while others note that their hair becomes brittle over time.
"...The breakage has dramatically reduced, and the texture has improved—my hair feels stronger and more manageable...." Read more
"...They are super dry and brittle. I used K18 after ONE wash with Redkin bonding shampoo, and my hair feels brand new!..." Read more
"...It shortens my shower time, extends the life of my conditioner, makes brushing my hair effortless, and leaves my hair looking healthy once..." Read more
"...It does exactly what it advertised to do which is strengthen your hair. I have ordered it and will order again. Thank you." Read more
Customers have mixed experiences with the hair mask's effect on dryness, with some finding it helps with dryness and frizz while others report it makes their hair super dry.
"...Second time trying it, it just left my hair dry...." Read more
"...it on and within minutes, my ends went from desert straw to moisturized silk...." Read more
"...on my hair I applied following the instructions however my ends continue to be dry after I finished the first bottle The size of the bottle is also..." Read more
"...I mean does my hair feel softer? Yes. Is it less dry, yes. But it hasn’t stopped breakage as significantly as I would like...." Read more
Customers find the hair mask expensive, with several noting that the bottle size doesn't justify the price.
"...I bit the bullet after seeing this all over social media. Is it spendy? Yes. But I would gladly pay again an again for this vodoo hair repair...." Read more
"...Softer hair. It's pricey, but it works." Read more
"...While it’s on the pricier side, its effectiveness and quality make it worth every penny...." Read more
"...It’s well worth the investment, and my hair has never looked or felt better. Highly recommend!" Read more
Customers find the bottle size of the hair mask too small, particularly noting that it doesn't provide enough product for shoulder-length hair.
"Yes, the bottle is TINY. However, I noticed a difference after one use!..." Read more
"...The brand's bundles are a nice idea but again, the high cost and dismal size of the product received do not match up...." Read more
"This stuff is an absolute miracle in a bottle...." Read more
"very good product, but the packaging is REALLY small for such an expensive product but next time i buy i’ll get the bigger size...." Read more
Reviews with images

Blondes have More Fun Until They Fry Their Hair
Top reviews from the United States
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- Reviewed in the United States on March 1, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseI wasn’t expecting it to be this small for the price haha! But it is an amazing product & by far the best leave in conditioner that has actually controlled frizz, and left my hair soft. I’ve bleached my hair several times which has obviously left my ends feeling like a straw, but this immediately left my hair looking healthy and hydrated. It does not leave your hair feeling thick and sticky and it smells great!
5.0 out of 5 starsI wasn’t expecting it to be this small for the price haha! But it is an amazing product & by far the best leave in conditioner that has actually controlled frizz, and left my hair soft. I’ve bleached my hair several times which has obviously left my ends feeling like a straw, but this immediately left my hair looking healthy and hydrated. It does not leave your hair feeling thick and sticky and it smells great!Small & pricey but so worth it!
Reviewed in the United States on March 1, 2025
Images in this review
- Reviewed in the United States on March 22, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseYes, the bottle is TINY. However, I noticed a difference after one use!
It says to skip conditioner, use the K18, wait 5 minutes, then add your hair products and style as usual. But with as thick as my hair is, I don’t skip conditioner.
I’ve been blonde for years and went back to my black roots. Used black box dye to cover up the random grays that would come through and got tired of that so started going back lighter. I got balayage and it ruined my hair. Tbh I don’t think the hair stylist knew what she was doing but that’s besides the point. My hair was falling out in huge clumps through out the day and when washing and brushing. The K18 has helped with the damage, added shine back to my hair, and lessened the amount of hair that falls out.
There’s not much of a scent to the product. It’s light weight. I use more than 4 pumps too. I use about 8-10 pumps. My hair is THICK and half way down my back length wise. I use this once a week and so far it’s been almost a month and I still have plenty left in the bottle. It’s worth a try if your hair is damaged from bleach 👌🏼
- Reviewed in the United States on March 3, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseThis stuff is an absolute miracle in a bottle. It has fixed my hair after an unfortunate visit to a salon which left my hair extremely bleach damaged hair. Seriously my hair felt synthetic after and looked fried. I noticed a difference after only using the product one time, which is only 4 squirts from the bottle. My hair was so soft, shiny, not a tangled hot mess and just looked healthier.
I bit the bullet after seeing this all over social media. Is it spendy? Yes. But I would gladly pay again an again for this vodoo hair repair. Now that my hair is "fixed" I only use K8 once a month and I will never be without.
- Reviewed in the United States on December 31, 2024Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseI cannot rave enough about the K18 Hair Mask—it has truly saved my hair! I used to pull my hair every day, causing so much damage and breakage. My hair was dry, brittle, and lacked any real shine or strength. After using this mask for a few weeks, the difference is incredible.
The formula is super easy to apply, and a little goes a long way. I’ve noticed my hair feeling softer, looking shinier, and overall much healthier. The breakage has dramatically reduced, and the texture has improved—my hair feels stronger and more manageable. It’s as if the mask has repaired the damage I caused over time.
I now look forward to hair care days because I can actually feel and see the difference. If your hair has been through a lot, this mask is a game-changer! It’s well worth the investment, and my hair has never looked or felt better. Highly recommend!
- Reviewed in the United States on March 24, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseUsed it once and it brought out the curls in my recent perm. Softer hair. It's pricey, but it works.
- Reviewed in the United States on March 11, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseI have waist long thick curly hair, that tends to get dry and has been dyed from time to time - but it does not have damage from bleach or highlights or using lots of heat. So far I have used this 3 times, and the difference is very noticeable - my hair looks so much healthier, shinier and more bouncy. I am planning to use this 1-2 more times in a row, and then switch to a maintenance mode of using it maybe once a month, as needed.
Tip on how to use it -you need to put it in your hands, then rub the hands together so it emulsifies and almost looks like you smeared white toothpaste on hands. Then apply it to hair, starting with the ends and moving up. I didn't know that the first time - it makes a big difference, as opposed to simply applying it out of the bottle. I am using 3-4 pumps each time, since my hair is quite long.
- Reviewed in the United States on October 7, 2024Size: 50 mlVerified PurchaseI fell in love with the K18 Leave-In Molecular Hair Mask about a year ago after my hairdresser introduced me to it. While it’s on the pricier side, its effectiveness and quality make it worth every penny. When I’m unable to splurge, I turn to my regular leave-in spray, Perfect 10 Lite.
As someone with thin, color-treated hair that tangles easily and suffers from damage, this product has been a game changer. It shortens my shower time, extends the life of my conditioner, makes brushing my hair effortless, and leaves my hair looking healthy once styled.
I recently purchased the larger size, fully aware of the cost. However, when I opened my package, I briefly thought I either ordered the smaller size by mistake or received the wrong item. I realized it was indeed the larger size I ordered and I debated returning it.
The true test came when I woke up with a legit rat's nest. I was so thankful I had this product on hand, as it made detangling much easier than previous times when I had nothing to help with the mess.
One note: I read a review suggesting that you should rub the product between your palms to activate it before applying it to your hair. That makes sense, and I’ll definitely give it a try. However, I find it quite unethical that the company leaves this step out of the instructions on the box and bottle. It feels like they might not want you to use it correctly so that you’ll need to buy more sooner—quite disappointing!
- Reviewed in the United States on February 13, 2025Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseI was really skeptical at first because it felt so odd to shampoo and not condition after.. but I followed its directions: I shampooed, towel dried my hair, and put this product in and left in for the 4 minutes.
My hair did feel softer, less rough, yes, but I have a lot of coarse curly hair (transitioning from heat damage)
I had to use like 7 pumps and this product is expensive. It made like 80% of my hair feel soft and the rest of it i had to use another leave in conditioner to take out the tangles my hair has. It’s an ok product but it’s my first time using it. Will continue using it!
Top reviews from other countries
- Maram AlmilhimReviewed in Saudi Arabia on November 3, 2024
5.0 out of 5 stars Love it
Size: 0.51 Fl Oz (Pack of 1)Verified Purchase👍🏻
- StellaReviewed in Sweden on February 15, 2025
4.0 out of 5 stars Good but tiny
Size: 0.51 Fl Oz (Pack of 1)Verified PurchaseStellaGood but tiny
Reviewed in Sweden on February 15, 2025
Images in this review
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ودادReviewed in the United Arab Emirates on February 14, 2025
5.0 out of 5 stars يستحق بالفعل
Size: 0.51 Fl Oz (Pack of 1)Verified Purchaseالمنتج رائع وسريع المفعول سأعاود شراؤه
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GabiReviewed in Spain on August 29, 2024
5.0 out of 5 stars Buen funcionamiento
Size: 50 mlVerified PurchaseTextura ligera, un pequeño pump da para media melena. Ideal para mantener pelo seco, estropeado o dañado. Leer bien el funcionamiento y el proceso. El olor podría mejorar, huele a químico. Percepción personal.
- KPReviewed in Canada on February 23, 2025
5.0 out of 5 stars Great product
Size: 50 mlVerified PurchaseMy hair was very damaged and whole this product is fairly pricey I felt that it really helped repair my damaged hair