Keratin is the molecular building block of human beauty—without this fibrous protein, humans wouldn’t have nails hard enough to polish, tooth enamel sturdy enough to withstand weekly brushings, or hair lush enough to style. Within each strand of hair, chains of keratin can be arranged in different molecular patterns, and this variation is what gives each head of hair its unique texture. For those who find their hair’s unique texture a pain to deal with every morning, those keratin bonds can be chemically rearranged with Brazilian Keratin Treatment. Stylists apply a keratin-rich solution that finds its way into each hair’s second layer, where it can chemically reprogram hair from an unruly, cigarette-smoking strand into a well-behaved member of the scalp’s society. The heat of a flat-iron straightens hair so that as the keratin molecules fuse to each strand, they’ll do so in the right position. The result of all this chemistry is a straighter and smoother look that can last for two months or longer, and, leaves hair glossy. Each treatment takes between 90 minutes and four hours to complete, depending on hair length and texture.