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full-size leave-in molecular repair hair mask
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.
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*Disclaimers
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
The Science Behind K18 Molecular Repair
See how our K18PEPTIDE™-powered mask reverses damage in 4 minutes for lasting + progressive hair health.
molecular repair for aging hair
Hair evolves with age. This is how to support your strands throughout the years.- Rebecca M.Verified BuyerReviewingLeave-In Molecular Repair Hair Mask Deluxe SampleI recommend this productRated 5 out of 5 stars17 hours agoMakes me hair feel like silk!
I love this stuff! I’ve got wavy, bleached hair and this is better than olaplex! Makes my hair go from hay to silk!
- Olena F.Verified BuyerReviewingLeave-In Molecular Repair Hair Mask Deluxe SampleRated 3 out of 5 stars4 days agoNice but small
I purchased the full-size mask and also received a deluxe sample of the Leave-In Molecular Repair Hair Mask. Because I own the full size, I can say that the product does help — I do see positive results in my hair. It feels smoother and healthier with consistent use.
That said, the sample itself is only enough for one application, so if someone is trying it for the first time, one use is really not enough to decide whether it’s a must-have or not.
My main concern is the value. The mask works nicely, but it gets used up very quickly. Realistically, you need at least three pumps per use, and the bottle is only 100 ml, so it doesn’t last long.
It’s also frustrating that larger, more affordable sizes are only available to licensed hairdressers. As a regular customer, you’re stuck paying the premium price, which honestly feels limiting and a bit unfair.
Overall, it’s a good product with visible benefits, but I’m still unsure if it’s truly worth the price for the amount you get.
KK18HairYesterdayThank you so much for your detailed and honest feedback — we truly appreciate you sharing your experience. We’re so glad to hear you’re seeing smoother, healthier results with consistent use. That’s exactly what we hope for.
With K18, less really is more. Because the formula is highly concentrated, most clients only need 1–3 pumps total, depending on hair length, thickness, and density. For many hair types, starting with 1 pump and adding more only if needed is key. Using more than necessary won’t improve results and can cause you to go through the product more quickly than intended. We also understand your concerns about value and sizing. We truly appreciate your perspective and your continued support. If you’d ever like personalized guidance on usage amounts based on your specific hair type, we’re happy to help. - Laura K.Verified BuyerReviewingMini Leave-In Molecular Repair Hair Mask 15 mLI recommend this productAge 55 - 64Hair Concern Chemical damage, Heat damage, Color-care, Frizz, Fragile/brittle hairHair Type Fine/Thin, Thick/Coarse, Grey Hair, Curly/CoilyMy Results Less Frizz, Visible Difference, Stronger Hair, Less Breakage, Shinier HairRated 5 out of 5 stars6 days agoThis is THE best product
I can’t not use this product. Sad when you get your hair done and come home to rewash it because you miss your product in your hair. This product changed my hair texture. It is the best!!
KK18Hair5 days agoThank you so much for your incredible review, Laura! We're absolutely thrilled to hear that our Mini Leave-In Molecular Repair Hair Mask has become such an essential part of your routine that you can't imagine going without it - there's no better compliment than knowing our molecular repair technology has transformed your hair texture so beautifully that even after a salon visit, you need to come home and use our treatment to feel complete! ❤️
- Lillian D.Verified BuyerReviewingFull-Size Leave-In Molecular Repair Hair Mask 50mLI recommend this productAge 18 - 24Hair Concern Heat damage, Fragile/brittle hair, Frizz, Split-Ends, Chemical damageHair Type Curly/Coily, Straight/Wavy, Medium DensityMy Results Less Frizz, Defined Curl/Wave Pattern, Cleaner, fresher hair, Less Breakage, Visible DifferenceRated 5 out of 5 stars1 week agoGood Progress So Far
I have used this product a few times so far and have already seen great results and improvements. I’d like to keep up with it consistently and come back with update photos!
KK18Hair5 days agoThank you so much for your incredible review, Lillian! We're absolutely thrilled to hear that our Full-Size Leave-In Molecular Repair Hair Mask is already delivering great results and improvements after just a few uses - there's no better compliment than knowing our molecular repair technology is working so beautifully that you're excited to keep up with it consistently! We'd love to see those update photos when you're ready to share your continued progress! ❤️
- Nancy J.Verified BuyerReviewingFull-Size Leave-In Molecular Repair Hair Mask 50mLI recommend this productAge 45 - 54Hair Concern Chemical damageHair Type Curly/CoilyMy Results Less Breakage, Bouncy HairRated 5 out of 5 stars1 week agoLove this hair mask
This mask has saved my hair!
KK18Hair1 week agoThank you so much for your incredible review, Nancy! We're absolutely thrilled to hear that our Full-Size Leave-In Molecular Repair Hair Mask has saved your hair - there's no better compliment than knowing our molecular repair technology is giving your hair the rescue it needed! ❤️
