The salon-grade hair mask that fixes 2 years of damage in 4 washes
Is this the right fit?
- Best for
- people who have bleached, color-treated, heat-damaged, or chemically straightened hair that snaps when wet, or anyone whose ends look fried after 2+ years of styling
- Skip if
- Pricey per ounce, so it's a salon-level investment, not a daily conditioner replacement
- Check before ordering
- Confirm the dimensions, exact model, included parts and return terms on the Amazon listing before ordering.
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K18 Leave-In Molecular Repair Mask is a patented bioactive peptide treatment that reconnects broken disulfide bonds inside the hair shaft. Unlike traditional masks that coat the cuticle, K18 actually rebuilds internal structure. The starter size is 0.5oz which lasts 4 to 5 treatments. After washing with shampoo, towel-dry until just damp, work a quarter-sized amount through mid-lengths and ends, wait 4 minutes, then style as normal. Do not rinse out. Best fit: people who have bleached, color-treated, heat-damaged, or chemically straightened hair that snaps when wet, or anyone whose ends look fried after 2+ years of styling.
Pros
- Rebuilds internal hair structure, not just a surface coating that washes out
- Works in 4 minutes of leave-in time, no rinse needed
- Visible difference in elasticity and softness after the first or second use
Cons
- Pricey per ounce, so it's a salon-level investment, not a daily conditioner replacement
Frequently asked questions
How often should I use it?
Once per wash for the first 4 to 6 uses to reset the hair, then once every 3 to 4 washes for maintenance. Heavily damaged hair benefits from every wash for the first month.
Do I rinse it out?
No, leave it in. Apply to damp hair after washing, wait 4 minutes, then style as normal. Do not rinse.
Will it work on virgin (uncolored) hair?
It works on any damaged hair, but the dramatic before-after results are most visible on bleached, color-treated, or heat-damaged hair. Virgin hair sees subtler softening.
Is the small bottle enough to see a difference?
Yes, the 0.5oz starter size is meant for 4 to 5 treatments which is the official 'before-after' window. Most reviewers report a visible difference by treatment 2.
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