K18 Leave-In Molecular Repair Hair Mask, Patented, Lasting Repair For Dry, Frizzy, Damaged Hair, Reverse Damage In 4 Minutes From Bleach, Color, Chemical Services + Heat
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To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
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Availability:
Only 10 left in stock, order soon!
Arrives
Sunday, May 31
Size: 50 ml
Features
- 4-Minute Molecular Hair Repair Treatment: A leave-in peptide hair mask designed to repair and reverse damage at the molecular level for stronger, smoother, more resilient hair in just 4 minutes.
- How It Works: Patented K18PEPTIDE repairs hair at a molecular level to reverse damage from bleach, color, chemical services, and heat*. The biotech-developed peptide mimics and clicks into hair's keratin structure to reconnect polypeptide chains and disulfide bonds for strength along the length + width of hair.
- Works on All Hair Types: Because our hair treatment works at the innermost layer of the hair rather than only targeting the outer cuticle like many deep conditioning hair masks, it's effective on all strands, even coily and curly hair.
- Boosts Strength + Smoothness: Helps improve texture, manageability, and bounce with a highly concentrated hair cream formula with detangling and softening benefits. Most see results after 2-3 uses.
- How to Use: Shampoo, skip conditioner, and apply 1-3 pumps of the leave in hair mask to clean, towel-dried hair. Let sit for 4 minutes, do not rinse, then style as usual. Use for 4-6 consecutive washes, then as needed.
Product Dimensions : 1.87 x 1.87 x 4 inches; 3.2 ounces
Item model number : K18-31005
UPC :
Manufacturer : K18
Best Sellers Rank: #116 in Beauty & Personal Care (See Top 100 in Beauty & Personal Care) #1 in Hair Treatment Masks
#1 in Hair Treatment Masks:
Customer Reviews: 4.3 4.3 out of 5 stars (29,545)
Item Form: Cream
Hair Type: Damaged
Product Benefits: "Real, lasting repair powered by K18PEPTIDE™ Hair like new in 4 minutes* Soft, strong, bouncy hair for everyone "
Additional Features: Travel Size
Package Type Name: Jar
Hair Conditioner Type: Leave-In Hair Conditioner
Unit Count: 1.7 Fluid Ounces
Number of Items: 1
Item Dimensions: 1.87 x 1.87 x 4 inches
Liquid Volume: 50 Milliliters
Item Weight: 3.2 Ounces
Size: 50 ml
Brand Name: K18
Age Range Description: Adult
Manufacturer: K18
UPC: 858511001029 858511001128 729162271362 729162270877 755801147958 726929222179 729162271317 729162271249 729162271096
Global Trade Identification Number: 28
Model Number: K18-31005
Manufacturer Part Number: K18-31005
Material Features: Natural
Active Ingredients: Water (Aqua) (Eau), Alcohol Denat., PropyleneGlycol, Cetearyl Alcohol, Dicaprylyl Ether, Cetyl Esters, BehentrimoniumChloride, Polysorbate 20, sh-Oligopeptide-78, Hydrolyzed Wheat Protein,Hydrolyzed Wheat Starch, Isopropyl Alcohol, Tocopherol, Phenoxyethanol,Potassium Sorbate, Citric Acid, Fragrance (Parfum), Geraniol, Linalool, HexylCinnamal, Benzyl Alcohol.
Recommended Uses For Product: Shampoo, skip conditioner. Towel-dry thoroughly. Apply 1-3 pumps from ends to roots (3-9 pumps for 15ml sized mask). Less is more. Wait 4 minutes, do not rinse.
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Sunday, May 31
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Size: 0.51 Fl Oz (Pack of 1)
I’m over 55 and have spent decades trying everything — from $9 to $144 per product — hoping for softer, healthier hair. I have 3a curls hidden under years of color, heat damage, and dryness. My hair would break and frizz so badly it looked like I had layers (I don’t). K18 is the first and only product that actually delivered on its promise to repair — not just coat — my hair. I was fully prepared to return this if it did not make a difference. It did. This isn’t a conditioner or mask. K18 uses a patented technology that works from the inside out. I used a clarifying shampoo, applied 6 pumps (very small pumps from the "try it" bottle!), finger-raked it through damp hair, waited 4 minutes, and then combed through. No rinsing, no other products. I let my hair air-dry, and it already felt softer and smoother with significantly less frizz. No fragrance -makes me happy. Important note: You do not need to rub this aggressively between your palms to "activate" it — that’s a common myth. Just rub your palms lightly so you can apply it evenly and let the science do the work. It works on the keratin molecules to repair your hair from the inside out. Friction is not going to make the molecules smaller. Don't know why people start these rumors. The next morning, I used my straightener on medium heat and was stunned. Instead of the usual dry straw, my hair was sleek, shiny, and bouncy. Even the ends curled beautifully — something I’ve never seen on my hair before. After four treatments, my hair now feels different, although the greatest results came after the very first use. My hair is softer, smoother, more manageable, with less frizz and more shine. Even in Florida’s 90°+ heat and humidity, it holds up — and I’m not using anything else but K18. A friend even asked to try it after seeing my results. It’s expensive, but absolutely worth it. I’ve already bought the larger bottle. I’m sticking with K18 — this changed everything for me. And to address the expense, the 50mL pump provides 50 pumps. That's 25 applications for me. My average thickness, long hair uses 2 full regular pumps. After the first 4 applications, you move to every 4 washes. That means after the first four treatments, I have 21 treatments more still in the pump bottle. For me, with super dry hair, that means it will last another 18-21 weeks since I only wash once a week, and an occasional "extra". I am going to guess I have taken at least $100 of products that did not work for me to the women's shelter over that time, meaning the waste was as much as this effective product that takes no time to use, packs easily in a suitcase, doesn't stink and IT WORKS! If you have super straight, silky hair, like Asian hair, or other non-porous hair, I do not think you are going to get the same results. You probably already have the kind of hair those of us with porous, damaged hair are looking for. Ask ChatGPT
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Reviewed in the United States on June 25, 2025 by GG
Size: 0.51 Fl Oz (Pack of 1)
For color or damaged hair this product work very well. Makes hair easy to comb through. Leave hair smooth and no frizz. Helps with damaged hair from coloring and drying. Convenient, start with bottom of hair ( ends ) up to the top and then no rinsing leave in the hair. . Great product . Brenda
Reviewed in the United States on May 13, 2026 by Brenda L.
Size: 50 ml
I originally bought this after hearing a trichology influencer I follow recommend it. My hair was only mildly damaged when I started using it, mostly breakage through the mids and ends from heat styling and years of hair processing. I actually use it after washing and before conditioning, even though that’s a little different from the directions, and it has visibly improved the breakage in my hair over time. The measured pump helps prevent wasting product, but I highly recommend researching the correct amount for your hair type because using too much is easy. I’ve used this pretty religiously for years now and my hair is noticeably stronger, fuller, softer, and much more manageable. It is expensive, but if you emulsify it well in your hands first it spreads more evenly and lasts longer. As my hair improved, I also found I didn’t need to use it as often.
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Reviewed in the United States on May 17, 2026 by LollieAnne
Size: 0.51 Fl Oz (Pack of 1)
Truly is an amazing product to use on your hair. My hair is soft and silky after use. Small bottle and expensive, but a little goes a long way. I have very long hair, and it worked beautifully on my hair
Reviewed in the United States on May 14, 2026 by aususa
Size: 0.51 Fl Oz (Pack of 1)
I was a bit shocked by how small the bottle was for the price, but let me tell you—it is worth every single penny. Before using K18, my hair would get greasy so fast that I had to wash it every other day. Since adding this to my routine, my hair stays clean, fresh, and lightweight for days at a time. A little goes a long way: You truly only need about 3 to 4 pumps. The trick is to rub it thoroughly between your hands until it turns white/emulsifies before applying. I’ve had my bottle for about two months now, using it 1–2 times a week, and I still have product left. Don't let the size fool you; it lasts! Highly recommend if you’re willing to pay $30 every three months.
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Reviewed in the United States on May 25, 2026 by Emily Dell
Size: 0.51 Fl Oz (Pack of 1)
I swear by this product! It's expensive but worth every penny. My hair is super soft and feels great. I split my hair in two parts and use about 1.5 pumps per side. I have boob length hair. Best leave in I have ever found. Fragrance is light but nice.
Reviewed in the United States on April 22, 2026 by Jennifer Flynn
Size: 50 ml
I use this product a lot last year like I think I used three or four bottles. I do a lot of dying and bleaching of my own hair. I know the product is meant to be used while going through the bleaching process. I personally use it after I get out of the shower once twice a week and when I used to use it that way last year, it worked really great, phenomenal even. My ends used to be very straw like, really puffy and frizzy. But here’s my problem. I just recently purchased this product again, which by the way the packaging has quite changed. I know a lot of of the photos in the reviews. They’re almost the same bottles, but I could swear mine used to be a little bit bigger for the exact price that I purchased it for. Another thing is maybe I just use a little too much this time, but it used to be an instant instantaneous soft silky feeling once putting it in my ends this time it feels grainy and like I just stuck yogurt in my hair, I will come back in a couple of days or weeks to let you know if it got any better but so far not quite happy just yet
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Reviewed in the United States on May 19, 2026 by Bella
Size: 0.51 Fl Oz (Pack of 1)
I wish I would have took a before picture. My hair was highlighted to the point where my cuticle was blown open. This last time I went to the Salon I was sooo disappointed in the condition of my hair went I left the salon- I would of hoped the Cosmetologist would Of listened to me and had seen my hair needed TLC. I seen ads for the K18 and thought I’d give it a try . After 4 uses I am so happy with the condition of my hair! After the 1 st use you can see it’s helping but it says to use after 4-6 washes. My hair is soft, there is no frizz, it is manageable, non greasy and it looks great. There is no fragrance that I can smell, it is just so easy to use as a leave in conditioner. It is 100% worth every penny! Make sure you follow the directions and you will be pleasantly surprised. :) Thanks K18
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Reviewed in the United States on May 14, 2026 by Christine