Your hair ultimately reflects the overall condition of your body. If your body is healthy and well nourished, your hair will be your shining glory.
If you are having any health problems or suffering from any nutritional deficiencies, your hair may stop growing or show damage.
Each individual hair survives for an average of 4 1/2 years, during which time it grows about half an inch a month. Usually in its 5th year, the hair falls out and is replaced within 6 months by a new one. Genetic baldness is caused by the body's failure to produce new hairs and not by excessive hair loss
Baldness is not usually caused by a disease, but is related to aging, heredity, and testosterone. In addition to the common male and female patterns from a combination of these factors, other possible causes of hair loss, especially if in an unusual pattern, include:
Hormonal changes (for example, thyroid disease, childbirth, or use of the birth control pill)
A serious illness (like a tumor of the ovary or adrenal glands) or fever
Medication such as cancer chemotherapy
Excessive shampooing and blow-drying
Emotional or physical stress
Nervous habits such as continual hair pulling or scalp rubbing
Burns or radiation therapy
Alopecia areata -- bald patches that develop on the scalp, beard, and, possibly, eyebrows. Eyelashes may fall out as well. This is thought to be an immune disorder.
Tinea capitis (ringworm of the scalp)

Some women also develop a particular pattern of hair loss due to genetics, age, and male hormones that tend to increase in women after menopause. The pattern is different from that of men. Female pattern baldness involves a thinning throughout the scalp while the frontal hairline generally remains intact.
Typical male pattern baldness involves a receding hairline and thinning around the crown with eventual bald spots. Ultimately, you may have only a horseshoe ring of hair around the sides. In addition to genes, male-pattern baldness seems to require the presence of the male hormone testosterone. Men who do not produce testosterone (because of genetic abnormalities or castration) do not develop this pattern of baldness.
Hair loss from menopause or childbirth often returns to normal 6 months to 2 years later
