At any single moment, at least 10 percent of the hair on your scalp is in a resting phase. The hair that is resting will fall out after a period of two to three months, and new hair will begin to grow in its place. The growing phase lasts between two and six years. During this phase, the average growth rate for hair is approximately one centimeter per month. At any single moment, approximately ninety percent of the hair on your scalp is in its growing phase. It is normally for you to shed each day as a part of this cycle, although there are people who experience hair loss at rates much higher than normal. This type of hair loss can affect everyone; men, women and children alike.

Excessive hair loss is caused by several factors, including illness or major surgery which cause stress-related temporary hair loss, hormonal problems, an under-active or over-active thyroid, childbirth-related hormones, medications like blood thinners, gout medications, chemotherapy, vitamin A, anti depressants and birth control pills. Infection of certain types can also cause hair loss, including fungal scalp infections in children. Underlying disease like lupus or diabetes may also cause hair loss. It is important to find out the cause of the excessive hair loss, to make sure it is not something that is detrimental to your health as well as your hairstyle.

Improper hair care can also cause excessive hair loss. Hairstyles or products that pull on your hair a lot can often cause traction alopecia, but your hair will grow back as long as the scalp has not scarred before the pulling has stopped. Hot oil treatments for hair and the chemicals used in perms may cause hair follicle inflammation which can also result in scalp scarring and sometimes permanent hair loss.

Common baldness is the term used to describe male-pattern baldness, or permanent-pattern baldness, the most common cause of loss of hair in men. Men typically inherit the pattern baldness trait, and some can begin to lose their hair at an early age. Hair loss typically results in a receding hair line and baldness on top of the head in male-pattern baldness.