On average, the human head has approximately 100,000 hairs. Each day, the average person loses 50 to 100 hairs due to brushing and washing the hair, but new hair constantly grows in its place.
Each hair on the human head grows between two to six years, then rests for a few months, after which it falls out. A new hair then replaces the previous hair, using the same hair follicle. Human hair follows a specific growth cycle with phases called the anagen, catagen and telogen phases. All three phases occur on the human head simultaneously, with different hairs in different phases of growth.