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HerDupes
K18

Leave-In Molecular Repair Hair Mask

Bond-repair treatment · 50 ml

$75

approx. retail · $44.36 / fl oz

Price checked 23 September 2026. Amazon's price today may differ.

1 dupe from $19, up to 89% less.Compare them

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Description

Leave-in treatment used on damp hair after shampooing, with no rinse and no conditioner for the first few uses. Works in about 4 minutes.

Key ingredients
  • K18Peptide™

Leave-In Molecular Repair Hair Mask dupes

Cost per fl oz

K18$44.36 / fl oz
COSRX$4.68 / fl oz

$56 less at checkout than the original.

Size
Original · K1850 ml
Dupe · COSRX120 ml
Key ingredients
Original · K18K18Peptide™
Dupe · COSRXTripeptide-132 HCl, Biotin, Soluble collagen, Hydrolyzed hyaluronic acid

What matches

Both rebuild broken keratin bonds with a low-molecular-weight peptide — K18Peptide in one, Tripeptide-132 in the other — and both are aimed at bleach, colour and heat damage.

What the dupe does worse

This one is rinsed out after a few minutes instead of left in, and it is silicone-and-oil heavy, so fine hair can be left with a slight film K18 never leaves.

More in Hair

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$75

$44.36 / fl oz