Hair facts People Like to Know.

Hair math
The average human head has about 100,000 hair follicles and about one to two hundred of them fall off each day.
The density of the hairs (follicles per square centimeter) is not the same on every person, in fact this changes from one person to another.
Hair alternates periods of growth and sleep. During the growth portion of the cycle, hair follicles are long and much like a bulb, and its hair grows at about a third of a millimeter each day. After three to six months, body hair growth stops. The follicle shrinks and the root of the hair grows rigid. After a period of sleep another growth cycle starts, and soon a new hair pushes the old one out from beneath. Head hair, grows for a long period and to a long length before being shed. The rate of growth is approximately 1.25 centimeters, or about 0.5 inches, per month.