What exactly is straightening?

Without going into technical details, I would say that the manipulation takes place in two stages. 1 - With a highly alkaline product, you must first artificially break the original organization of keratin molecules (the fiber that our hair is made) to impose a new hair structure and make it totally malleable. This, until the hair no longer pit resistance and achieve the desired stiffness. 2 - Then apply an oxidizer, which neutralizes the previous action and recementing the fibers together in the desired shape.