Hair consists 90% of a biological polymer, α-keratin, and about 10% water, which modifies its mechanical properties. This α-helically coiled protein is further wound into supermolecular coiled-coil microfibrils, many of which are held together with a protein glue to form long macrofibrils, which are packed inside dead hair cells about 100 µm long by 3 µm across. Several of these associate to form one strand of hair, which is covered with tiny surface scales.
By the time your hair emerges from under the skin it is DEAD. You will see many shampoos and conditioners that contain vitamins and minerals; these vitamins and minerals do absolutely nothing for the hair or scalp. Since hair is dead, it can't be helped by any additional vitamins and minerals. And these substances are not absorbed through the skin; they have to be ingested to be of any use to your body.