Hair keratin is a protein used in cosmetic products and treatments to strengthen, smooth and improve the look of damaged hair. Although hair is naturally made of keratin, chemical treatments, heat styling and mechanical stress can weaken its structure, leaving it brittle and dry. Hair care products containing keratin help temporarily fill and reinforce damaged strands.
In cosmetics, hydrolyzed hair keratin is most commonly used. It’s broken down into smaller protein fragments that can penetrate the hair shaft and repair damaged areas. It can be found in shampoos, masks, conditioners and regular hair treatments. With consistent use, hydrolyzed hair keratin can improve elasticity, reduce breakage and enhance shine.
There are also salon keratin treatments designed for smoothing and straightening hair. These combine various forms of hair keratin with chemical agents and require heat fixation (using a hair straightener) to create a protective layer around the hair shaft. The result is sleek, shiny and smooth hair that’s easier to style, with straightening effects lasting several weeks. These treatments are especially popular for curly or wavy hair. They are primarily aesthetic rather than restorative, and their effectiveness and safety depend on the product formulation and the stylist’s expertise.