What is a Keratin Hair Treatment? The Essentials.

Frizz, fuss, unruliness. When it comes to a range of common hair frustrations, a keratin hair treatment may be just the answer. It’s a popular treatment that includes a solution containing keratin to your hair to make your mane smoother, shinier and easier to manage. Discover everything you need to know about keratin treatments and other innovative haircare options below.

article-duration
6 min read
L'Oréal Professionnel Team
25/02/2026

Your questions and our answers on keratin hair treatment.

  • What is keratin?

    It is the primary protein that forms the very core structure of your hair, residing at the deepest level of the fiber.

  • What is a keratin hair treatment?

    A keratin hair treatment is a chemical protein treatment designed to smooth the hair cuticle.

  • What is keratin alpha?

    It is the primary protein that forms the very core structure of your hair, residing at the deepest level of the fiber.

  • How does keratin alpha determine the hair’s shape?

    Alpha-keratin is the fundamental structural protein that forms the hair. Its internal helical arrangement, along with the extensive network of bonds within the hair's cortex, dictates the strand's overall geometry, and ultimately determines if hair appears straight, wavy, or curly.

  • Does Keratin Alpha Sleek range contain keratin?

    Keratin is an animal-derived ingredient, also found in human hair. These products don’t contain keratin, but reprogram hair from deep inside the fiber at Keratin Alpha level, reshaping Keratin Alpha chains for 2 weeks of smooth, frizz-controlled hair. It is a revolution in semi-permanent at-home smoothing.

All you need to know about hair.