The normal cycle of hair growth lasts for 2 to 6 years. Each hair grows approximately 1 centimeter (less than half an inch) per month during this phase. About 90 percent of the hair on your scalp is growing at any one time. About 10 percent of the hair on your scalp, at any one time, is in a resting phase. After 2 to 3 months, the resting hair falls out and new hair starts to grow in its place.
It is normal to shed some hair each day as part of this cycle. However, some people may experience excessive (more than normal) hair loss. Hair loss of this type can affect men, women and children.