Leave-In Molecular Repair Hair Mask review
Read this before you use it
More than any other product on this site, K18 fails when it is used wrong — and the instructions are counter-intuitive enough that most people do use it wrong.
- No conditioner first. Conditioner coats the shaft and physically blocks the peptide. This is the number one cause of "it made my hair greasy".
- Damp, not wet. Water dilutes it.
- Four pumps for shoulder-length hair. Not eight, not a palmful. It is a leave-in — excess has nowhere to go.
- Four minutes, then do not rinse.
Nearly every negative review describes one of those four mistakes.
What it does differently
Olaplex reconnects disulphide bonds. K18 uses a short biomimetic peptide designed to reattach broken keratin chains from inside the shaft. Different mechanism, faster action, and on severely damaged hair the difference in elasticity after one treatment is genuinely noticeable.
The value question
A 50ml bottle gives roughly fifteen treatments — about $5 each, against $2.50 for Olaplex No.3. On heavily bleached hair the extra is defensible. On hair that is merely dry it is money spent on a problem you do not have.
Where it disappoints
Fragranced with no unscented option. The bottle is small for the price. And the four-minute window is a real constraint if you are in a hurry.
