What causes hair loss?
Hair loss, or alopecia, is a common disorder and can be due to many causes. Human hair undergoes phases of growth and rest during their life span. The growth phase is called anagen; 80% of the scalp hair is in this phase at any point of time. 20% of the hair is in the sleeping phase called telogen. It has been estimated that the scalp normally contains about 100,000hairs. Therefore, the average number of hairs that can be lost in a day is about 100. Hair loss can be of several different types, including alopecia areata (temporary hair loss in a coin-shaped patch), telogenef fluvium (temporary hair loss secondary to a stressor on the system), and androgenetic alopecia (male-pattern hair loss). The most common, male pattern hair loss is seen during the 20s or early 30s by gradual loss of hair, chiefly on the top of the head and in the angles at the frontal hairline. It is thought to be due to the male hormone combined with genetic factors.

Is stress a factor in hair loss?
Stress does not cause hair loss, but it aggravates the condition. A type of hair loss called as Telogen effluvium occurs after an insult to the system. The most common cause is pregnancy. This can result in extensive and worrisome hair loss in women in the first few months after the birth of a baby. It is, however, temporary and returns completely.

What is DHT and how is it involved in hair loss?
DHT, or dihydrotestosterone, is an active form of the male hormone testosterone. Studies suggest that DHT levels can harm hair follicles in a genetically predisposed person, eventually causing baldness. The chemical conversion of testosterone to DHT, if blocked can prevent hair loss. There are hair restoration products that target this reaction. Few examples are finasteride, a prescription medicine and an active ingredient in Propecia. Finasteride blocks the chemical reaction that converts testosterone into DHT, thereby making the hair follicles active again make new hairs.

What is the relationship between genetics and hair loss?
Although not the primary cause of male-pattern hair loss, genetics does have a significant role in male-pattern hair loss. It is, however, polygenic, in that there is more than one factor at work. It is not clear whether having an affected mother or an affected father predisposes descendants to greater risks.

Can hair loss occur in young adults?
Male-pattern hair loss typically is seen from 20s and early 30s, but can also be found as early as 15. Hair loss in young adults may also be due to other causes like Alopecia areata and telogen effluvium, can occur in children as young as one year of age. Genetic factors may also contribute to hair loss.

What can be the cause of a sudden loss of a large mass of hair?
Sudden loss of large mass of hair can be due to stress caused by illness, high fever, pregnancy, extreme weight loss or gain, and drug use; however, it is temporary and reversible. This happens when the hair cycle is disrupted and more hair shifts to the resting phase. This type of hair loss is temporary and full re growth should be expected.

Do shampoos and other hair products cause hair loss?
Some strong chemicals or products that may cause allergy can initiate hair loss. Shampoos are designed to be as safe as possible. However, the sensitivity may differ from person to person. Caustic hair dyes, straighteners, and other products can certainly cause inflammation of the scalp and result in hair loss.

Can my hairstyle cause my hair to fall out?
Certain hairstyles can contribute to hair loss, most notably styles involving tight braids or pull-backs. This form of hair loss is called traction alopecia. This occurs when the hair is pulled tightly back and fastened at the base of the skull, or braided into tight braids or rows. Exposure to this type of hairstyle over long periods can result in a scarring alopecia, with no potential for re-growth.