Hair is ‘dead’ tissue, the main component of which is a protein called keratin. This protein is also present in nails. Nutrient-rich blood nourishes the hair follicle allowing the hair to grow. Hair grows about one and half centimetres a month, constantly replacing hair that is lost normally every day. Hair is indicative of general health: stress, poor diet or hormonal changes may have an adverse effect on hair growth. Genetic factors, immunity problems and underactive thyroid may also affect hair health.