A Brazilian blowout is a type of hair straightening treatment that uses keratin to smooth and straighten your hair. A silicone-based serum is applied to the hair and then sealed in with heat. This creates a protective layer around each strand of hair, which helps to keep it smooth and straight. The main benefit of a Brazilian blowout is that it leaves your hair looking and feeling incredibly smooth and silky. It can also help to reduce frizz, making your hair more manageable.